To test injectors remove one from it's whole and cover the whole with a rubber stopper (chemistry labs are good sources).
Stick the injector in a beaker (chemistry labs are good sources).
Fire up the engine and watch the spray pattern.
Shut it down.
If you find an injector not "pulling it's weight", don't commit it to the grave yard just yet. Disconnect it from the fuel line. Put fuel line in beaker and push down (or pull up depending on engine) the air flow plate and hold, letting a few tablespoons of fuel run out.
Let go of plate.
Turn injector upside down a shake it (like you would shake a thermometer) vigorously over a clean white sheet. If you see a bunch of brown stains, your injectors might just have a bunch of crap accumulated inside that Techron can't take care of. Take GUMOUT an jam that little red tube into the injector and spray some into it. It's a tight fit so some pressure will back up (wear goggles). Shake the injector out again. Do this a few times.
Reconnect to fuel line and check spray pattern again.
If the injector srpay patten is better, the injector was clogged and this might save you a few bucks at $25 for a new one.
Michael
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My 142 had sat for a number of years before I got it and the K-jetronic (continuous, not mechanical) system was severely gummed and varnished up from the old gasoline. Since I potentially had to replace everything and the 142 wasn't my primary source of transport, I had nothing to lose by doing whatever was necessary, up to and including destroying the particular part, in trying to unclog the system.
I started by emptying the old gas from the gas tank, then removing and soaking the in-tank fuel filter in varnish remover for a day until it was cleared. The fuel pump was frozen and replacements for these high-pressure (50-70psi!) units were $100+, so I pulled it, disassembled it, cleaned it, put it back together and it worked again. It worked well enough to promptly blow out the aged fuel line up in the engine bay on the upstream side of the clogged main fuel filter. Both were replaced and now I had fuel into and out of the fuel distributer. I was extremely grateful that the fuel distributor hadn't gummed up or rusted and worked on the first try.
The injectors were plugged. They got the GUMOUT bath as per Michael's post and were still plugged. More soaking and they were still plugged. So I modified the end of my 110+psi bicycle air pump so I could screw the injectors into it to get a good seal. A couple of good pumps and they each opened. More soaking and more pumps and I got something resembling a good spray pattern.
I put them back in and it ran.
/\ Lawrence Buja Climate and Global Dynamics Division
\_][ southern@ncar.ucar.edu National Center for Atmospheric Research
\_________________________Boulder,_Colorado___80307-3000__________
> My 142 had sat for a number of years before I got it and the
> K-jetronic (continuous, not mechanical) ...
Not to be too anal, but shouldn't that be "(continuous, not ELECTRICAL)"?
> The injectors were plugged. They got the GUMOUT bath as per Michael's
> post and were still plugged. More soaking and they were still
> plugged.
Yeah, just soaking them won't cut it since the GUMOUT won't get into the injector unless you jam that little red tube that GUMOUT comes with into the injector and blast the inside.
I didn't mention that I ordered *1* new injector just in case one of them was bad or I scrweed one up somehow. It was interesting to note that the spray pattern on the new injector was significantly better than the best old injector after it was cleaned so there's something to be said for replacing with new injectors on a car that has 150,000 miles (mine).
Also interesting to note is that Techron isn't very effective with this type of gunk. It IS however effective at PREVENTING the buildup, but it's kind of pricey to add it every tankful.
> So I modified the end of my 110+psi bicycle air pump so I
> could screw the injectors into it to get a good seal. A couple of
> good pumps and they each opened. More soaking and more pumps and I
> got something resembling a good spray pattern.
Nifty idea! How did you modify the pump, I might like to try that!
Michael
>From: mm@lectroid.sw.stratus.com
>Message-Id: <9108261546.AA12447@lectroid.sw.stratus.com>
>To: southern@neit.cgd.ucar.edu
>Cc: volvo-net@me.rochester.edu
>In-Reply-To: Lawrence Buja's message of Mon, 26 Aug 91 9:02:50 MDT <9108261502.AA09905@neit.cgd.ucar.EDU>
>Subject: My experience with reviving a K-Jetronic system
>> My 142 had sat for a number of years before I got it and the
>> K-jetronic (continuous, not mechanical) ...
> Not to be too anal, but shouldn't that be "(continuous, not ELECTRICAL)"?
>> The injectors were plugged. They got the GUMOUT bath as per Michael's
>> post and were still plugged. More soaking and they were still
>> plugged.
> Yeah, just soaking them won't cut it since the GUMOUT won't
> get into the injector unless you jam that little red tube
> that GUMOUT comes with into the injector and blast the inside.
i find this quite interesting. i drove 1972 142 and 1973 145 fuel injected models before my current 245. i had a total of about 190k miles on the pair. i never had an injector clog in any obvious fashion. volvo replaced the injectors on the 1972 via a factory recall in 1976, and i changed all the injectors on the 1973 when i had the engine rebuilt. i always used the cheapest leaded gas available. Right now the dealers all sell you an injector cleaner at every tune up for the 245, even though the current gasolines are formulated not to vlog injectors, according to i think it is bmw tests. they also say that you should use the most expensive gas around. have the injectors changed, or is the current injection system inferior to the one used in the '72-'73 cars. i suspect that the latter is the case. with all these precautions, the car seems to need an injector cleaning every serice period. Certainly it drives better after the cleaning.
when i say i used the cheapest leaded gas available, i mean it: i used sellers like town pump and marvin the stinker when touring the country. (that for those of you who know the mountain states.)
right now our second car is a 1977 datsun 810 (the 6 cylinder injected sedan version of the 280z engine.) my mechanic tells me that the injection system is an improved version of the bosch system used in the '72-'73 years. in fact he calls it a perfected version (there were a lot of people who had problems with that injection system in the volvos.) it seems to run fine on the cheapest gas around (mechanics recommendation.)
any other experiences with that injection system to report?
> i find this quite interesting. i drove 1972 142 and 1973 145 fuel
> injected models before my current 245. i had a total of about 190k
> miles on the pair. i never had an injector clog in any obvious
> fashion.
O, I used the word "plug" and it was a bad choice. Partially obstructed would probably describe it better. Suffice it to say that the spray pattern was distinctly difference (better) after cleaning the injector and also compared to just replacing it.
On your 72 and 73 you might not notice much difference with a lousy spray pattern, but with my '81 V6 there's a remarkable difference in idle, and acceleration.
> now the dealers all sell you an injector cleaner at every tune up
> for the 245,...
Call 1-800-TECHRON.
> even though the current gasolines are formulated not to clog injectors,...
SOME DO, some are advertised to, but don't.
> changed, or is the current injection system inferior to the one used
> in the '72-'73 cars.
Not much different, however, I believe that quality of fuel available since the 70's crisis has gone down hill. The alcohol rips the crap outa the plastic lines and lots of tiny little bits of black crud clog the injectors. The mechanical injectors aren't as sensative as the electrical however.
> these precautions, the car seems to need an injector cleaning every
> serice period. certainly it drives better after the cleaning.
If they are using TECHRON, that could just be your intake valves getting cleaned up that makes it run a bit better.
> that the injection system is an improved version of the bosch system
> used in the '72-'73 years. in fact he calls it a perfected version
> (there were a lot of people who had problems with that injection
> system in the volvos.)
You certainly have my attention. I'll be looking into what improvements have been made by Datsun.
> any other experiences with that injection system to report?
Wouldn't have an electrical system after using this one.
It's easy to diagnose/fix.
Michael
>> My 142 had sat for a number of years before I got it and the
>> K-jetronic (continuous, not mechanical) ...
> Not to be too anal, but shouldn't that be "(continuous, not ELECTRICAL)"?
Yup, once again illustrating the dangers of reaching for the Reply button before reaching for that first cup-o-mud in the morning.
>> So I modified the end of my 110+psi bicycle air pump so I
>> could screw the injectors into it to get a good seal. A couple of
>> good pumps and they each opened. More soaking and more pumps and I
>> got something resembling a good spray pattern.
> Nifty idea! How did you modify the pump, I might like to try that!
It's quite simple. Slowly increase the opening on the business end of the pump with a round, rat-tail file until you get a thread of the injector to take. Screw in the injector until you get a seal between it and the rubber bit on the inside of the pump head. Fill the injector with your favorite toxic cleaning material, carefully screw it into your pump and give it a hearty pump.
/\ Lawrence Buja Climate and Global Dynamics Division
\_][ southern@ncar.ucar.edu National Center for Atmospheric Research
\_________________________Boulder,_Colorado___80307-3000__________
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Having replaced the inectors on my '84 GLT this weekend (at 160k they've seen their days) I decided to get curious and hacksaw open one of the old ones. This is what it looks like:
|-----------spring
___________________________|____
. | |
. ` |\ \ \ \|
* . O|========(| <---- nozzle
` . |\ \ \ \|
________________________________|
If you draw a straight line between the * and the .'s you will have the top of an triangle from the side view. From the top, the triangle is flat on both sides and has a SCREEN through which the fuel flows. This explain the brown crud that came out of the ones I cleaned. It also explains why when I cleaned one, the spray pattern got worse (I loosened some crud up and it clogged the screen more/differently).
Using the spring retainer from one of the butchered ones, I'm able to hold the injector open fromt he outside and force fuel in the opposite direction to back flush the screen.
Also, I'm looking for the OEM 15" steel wheels off an '90 or '91 700 series. Anyone?
Michael
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Michael G. Palmer confirms:
>Then one day <Herman L. N. Wiegman> said:
>> FIRST THINGS FIRST!!! CHECK THE F@#!$*& ELECTRICAL CONECTIONS!
>I wholeheartedly second this!!
This has become a rule with me.
Amazingly, a very similar thing just happened with my 142 too this last weekend. Maybe it's the increased thermal expansion that comes with the warm day/cold night temperatures time we're starting to experience.
My 142 had been getting harder and harder to start. Then, I was at the local shopping center and it refused to start at all. The engine would momentarily catch when the cold start injector fired, but then it would go into it's no.gas stance (i.e. turns over just fine, but the injectors are dry and won't fire). So, I towed it back home to fix.
With the injectors dry, I figured that the fuel pump had failed. But since pulling the pump is such a pain, I decided to double check the electrics first. Ignition on, air cover off, I lifted the air flow plate and didn't hear the fuel pump relay click. Things are looking up. I check for 12V into the relay and there's none. Get out the Haynes, Where is the juice supposed to be coming from? Off the side of the coil where the lead from the Capacitive Discharge box comes in. Check the voltage there and after scratching the metal a bit, there's 12V. Check continuity to the relay and there's nothing until I scratch the metal some. Get out the brillo pad, clean all the connections up and it starts on the first try.
/\ Lawrence Buja Climate and Global Dynamics Division
\_][ southern@ncar.ucar.edu National Center for Atmospheric Research
\_________________________Boulder,_Colorado___80307-3000__________
For those who have written about the poor drivability problems on their 240's (stalling, hesitation, etc.), don't forget the tech tip in the recent IPD newsletter sent in by someone with these same problems. Check the FI lead at the positive battery post, and also the FI fuse and it's holder near the battery junction box. The guy that wrote in said the problem was caused by corrosion at the battery connection which reduces the voltage to the FI computer. This voltage reduction was causing him all sorts of problems. (Engine dieing, hard starts, poor idle) He replaced the battery terminals and replaced the bolts that squeeze it with stainless. This solved all his problems. The corrosion was not that visible and tightening the connection will ot not help. The is also a Volvo bulletin out that specifies checking the FI fuse and it's holder at the regular maintenance checks. Corrosion here causes increased resistance. This causes heat which further deteriorates the connector. Look for discoloration or melting at the fuse terminals. The bulletin says to replace this connector is there are any signs of problems and there are poor drivability complaints from the owner.
--Chris Corey
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Yo SS,
This damn mailer has now done in this letter 3 times, user friendly as it is. Uh huh. Anyway, you're listed as having an '80 240 so I'll assume you have the CI injection. There are several things that I have done that seemed to have helped, and you seem to have the same problems.
The oil in the airbox you mentioned, this is not necessarily a problem, but you have to keep the airflow sensor clean. Take the hose from the airbox to the airflow sensor off, and look inside. Is it oil-gummy? Get out your carb cleaner. If you are planning to buy a new bellows, then remove it. It will probably rip if it is old. Move the sensor plate up and let it down. What you are looking for is any kind of binding or resistance in the movement of the plate. Lots of carb cleaner sprayed in the direction of the fuel distributor should cure the gummies. Make sure you baby the airflow sensor (its rather delicate) and make sure the vacuum seal at the bellows is not leaking.
The cold start injector could be causing your morning woes (mine are cured by coffee!). Take it out with the engine cold, leave the electrics hooked up to it, and switch on the ignition. Should spray for a few seconds (point it into a jar). If no spray, check for voltage there.
Poor running can also be caused by dirty injectors. You can take them out and lift the airflow sensor plate with the ignition on (you may have to bypass the oil pressure sender - some do some don't, and I'm not sure what to do about the frequency valve if you have Lambda). You're looking for a nice mist, not a drip drip drip. Haynes also recommends a leak test - lift the plate with the ignition off, if you get more than one drop in 15 seconds it the injector fails. Or if they all fail the possibility is that the pressure is too high.
I run 20 degrees of advance at the distrubutor. With this, the power is good, especially over 3500 rpm, (I have also been known to run the cam a notch advanced at the cam, which accentuates the power over 3500 rpm). I get ping up around 90-95 mph (only in Canada, of course).
This is the nasty part. Sorry. I had a cracked head, which I did not even know until I had the car a year and a half, had driven from South Florida to Seattle, WA, and then here to Rochester, N.Y. Smell your spark plugs for an antifreeze smell, look on them for some green deposits, and watch your temp gauge for unusual behavior (or is behaviour where you are?)
Don't feel too bad, SS. It takes 3-5 hours of my time a week just to keep the wagon on the road. Is it worth it? Fiats are pretty cheap at the moment...
roman
P.S. I will now attempt to mail this letter for the 3rd time...
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There are several factors that effect the economy of a car, and also the gas that it likes. To make my life simple, let me call `tune' the set of variables which includes air/fuel mixture and ignition advance (i.e. rich, and 40 degrees before top dead center (BTDC)). For any given engine, the tuning of the engine will make a difference in what fuel it requires to produce the optimal power.
In general, running slightly rich (12:1) compared to the "perfect" mixture (14:1) gives a slight increase in torque. It will also produce more polutants and burn slightly cooler. Going lean (i.e. 16:1) will burn cleaner and hotter with a slight decrease in torque.
Lean and rich come into place as one of the factors that determines any particular engine's tendency towards pre-detination (pinging). This is because the temperature is changed by the mixture. Another factor is the amount of advance in the timing. The more the advance, the more the power, but the more tendency to ping.
To make matters more interesting, the shape of the combustion chamber, the shape of the intake and exhaust ports and valves, and the temperature of the intake air all play a part in determining both the efficiency of an engine at any given rpm for any given state of tune. They also effect pinging. (Actually, if your car is pinging, it is not running as efficiently as it could.)
Now for some numbers:
My '87 740 Turbo recommends using 92+ octane fuel for stock settings. With 94 Octane fuel, I can increase the ignition advance to about 22 BTDC and the turbo boost up to 14 lbs without pinging. The result is a lot more power and a lot shorter clutch life.
My '70 140 with pro-rally motor likes to run 94 octane, although it can run 89 when pushed (i.e. its 2:00 AM on Sunday morning and we 200km from a city. You take what you can get.) The car tends to run somewhat rich, except at full throttle at high rpms. Because of this, I can get away with 25 degrees advance on low quality fuel. The car still has stock compression and a stock head, but I am looking at some serious head work soon.
My '65 122s used to require octane boost with every take of 94 octane with the stock (20+BTDC) timing. I was starting to get really tempted to start filling it up at racetracks and airports. I changed the head to a ported/polished/milled B20 E (Fuel injected = bigger valves) head and a HD head gasket (slightly thicker). I also took time to decarbonize the pistons. The car now is happy with anything from 92 up, and has lots more power at high rpms.
-- John
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Howdy All,
On the subject of carbon in the combustion chamber, not only will the carbon raise the compression ratio, but in some instances will retain enough of the heat from combustion to cause pre-ignition (detonation). Another factor which will play into the scene, as John Werner mentioned is the state of tune that the engine is in. A engine that runs rich will have less of a tendancy to suffer from pre ignition, but will not run as efficiently as a correctly produced engine (it also produces lots of nasty Hydrocarbon emissions as a by product). On the other hand, a lean engine will suffer from detonation with little provocation, although less fuel is used and fewer hydrocarbons are produced, the engine will run hotter and also will produce more nasty Nox emissions than a correctly tuned engine. (B.T.W. Although a diesel engine produces lots of particulate matter "soot", they *in general* produce fewer Hydrocarbons and NOx emissions than a gasoline engine.)
For those of you who may be blissfully ignoring the detonation that your car experiences, it is a serious threat to your engine's life. I remember being shown what detonation can do to an engine when I was going through ground school a few years back, and there I was shown a piston which had a hole burned through it. The piston was from an engine that had been run lean, probably *extremely* lean, and the resulting detonation is what caused this. This was probably an extreme case used to make a point, but detonation over time at the very least can cause pitting in the combustion chamber. This alone should be enough of a reason to make the move to a higher octane gas if your car is "pinging" a lot.
John A.
John_C._Ackerman.Wbst311@xerox.com wrote:
>A engine that runs rich will have less of a tendancy to
>suffer from pre ignition, but will not run as efficiently as a correctly
>produced engine (it also produces lots of nasty Hydrocarbon emissions as a by
>product). On the other hand, a lean engine will suffer from detonation with
>little provocation, although less fuel is used and fewer hydrocarbons are
>produced, the engine will run hotter and also will produce more nasty NOx
>emissions than a correctly tuned engine.
I think this is somewhat misleading. An engine may be "correctly tuned" and still be running somewhat richer or leaner than a pure stoichiometric mix. The reference point for rich or lean is the stoichiometric mixture at which the proportion of fuel and oxygen is balanced in the ratio required for perfect combustion. There is nothing inherently "correct" in tuning to this point, in fact tuning must consider desired results, which may be maximum power output or maximum economy (both of which tend to be obtained by tuning for mixtures richer or leaner than the pure stoichiometric mix).
A "rich" mixture has more fuel than the oxygen will fully combust, thus the increase in unburned hydrocarbons. A "lean" mixture has excess oxygen, which is available to burn nitrogen in the air to produce NOx. The energy and power characteristics reflect the various reactions and the composition of the resulting products and their properties. None of the characteristics are absolute polarities, they are points on a continuum centered around the stoichiometric mixture supporting perfectly balanced combustion.
>(B.T.W. Although a diesel engine produces lots of particulate matter "soot",
>they *in general* produce fewer Hydrocarbons and NOx emissions than a gasoline
>engine.)
Can anyone explain why? I would expect that the unburned carbon constituting particulate soot would indicate incomplete combustion and thus imply unburned hydrocarbons. This would make low Nox emissions understandable, but leaves the question of why hydrocarbon emissions would also be lower...
>I remember
>being shown what detonation can do to an engine when I was going through ground
>school a few years back, and there I was shown a piston which had a hole burned
>through it. The piston was from an engine that had been run lean, probably
>*extremely* lean, and the resulting detonation is what caused this. This was
>probably an extreme case used to make a point, but detonation over time at the
>very least can cause pitting in the combustion chamber.
Are you sure detonation caused the burned piston? A lean mixture burns much hotter, it was always my understanding that this caused burned pistons even if detonation did not occur.
Also, you are probably right that this was being used to make a point. "Ground school" implies aviation, and failure of aircraft engines in flight is somewhat more serious than failure of automotive engines on the road. Aviation engines are generally aircooled, so the temperature effects are much more extreme and noticable because of factors like density altitude and temperature gradients. Aviation engines are also unlike automotive engines because they require operator control of mixture variations, providing much greater opportunity for screw-ups like running over-lean.
Generally the only burned automotive pistons I have ever heard of were in racing applications or once from a friend's do-it-yourself rebuild (with carb tuning likely just an unscientific approximation). My concern over detonation has always been more along the lines of bottom end life, as the shock effects hit bearings, rods, pins, crank, etc., and perhaps top end and head gasket as well, also due to shock effects. I had never thought of pitting in the combustion chamber as a danger, although I am sure that conditions producing detonation would certainly not be good for combustion chamber and piston surfaces.
In general, detonation is not a good thing for your engine. Minimizing it is definitely a good idea.
--bruce
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Are you sure someone is not syphoning gas from your tank?-) Actually, I think the clue may be in the fact that when you cleaned the injectors with injector cleaner, the mileage went down. I suspect that the car had been run for a long time with either clogged injectors, or some other obstruction in the fuel system. Over time, the tuning of the car had been adjusted to take into account the decreased flow of fuel. When the injectors had been cleaned, the car probably started to run richer then it previously had because more fuel is now able to get through. This will certainly cause a drop in fuel economy, and depending of the previous state of tune of the engine, a decrease in power/performance.
I am harder pressed to explain why the economy would go down after changing the ignition and fuel injection points. My first order guess would be that the timing if no longer set right. Does the car have a tendency to ping under heavy loads. [A good test for pinging is to find a real steep hill and go up it at the slowest speed possible in the highest gear. (i.e. 25 mph in 4 od.) I am not quite sure why it works, but I read it in a Haynes manual and it does seem to work for every car I have tested.] It is also possible, but unlikely, that the fuel injection points were really badly corroded to a point that they only worked occassionally. If they were not triggering all of the time, the car may have been tuned to compensate. When they were cleaned up, the fuel computer received more pulses and started sending more fuel to the engine.
A good way to check for both of these is to check the exhaust while the car is running. Start the car, let it get to running temperature (i.e. drive to work, shoping, etc.) and then get out with the car running and check the smell of the exhaust. Don't stick your face in the exhaust, but use your hand to either deflect some of the exhaust towards your face or to waft it towards your face. Another trick is putting a piece of white cloth in the exhaust path. Either way, if you detect a strong smell of fuel, you are running rich. If you can see the exhaust as a blueish smoke, you are running very rich. (Don't confuse this with the white steam that comes out when the car is warming up to temperature.) I know this will work for checking the mixture on cars without catalysts. I am not quite sure what the catalyst will do. It is also one of the method suggested for helping tune carbs where smog checks are not a way of life. [BTW: If any one is interested, I can give a short lesson on tuning SU (and to some extent Stromberg) carbs at the Volvo-net meet, or maybe even by E-mail.]
-- John
[John mentioned that he thinks the problem is rich running due to newly cleaned fuel injectors.]
Another slant is that it's running rich due to partially clogged or aged fuel injectors. When the injectors begin to fail or get partially clogged, they will not produce a mist, but instead shoot a stream of fuel usually favoring one side of the injector nozzle. What happens is that the fuel is not atomized correctly and the fuel, or some of it at least, condenses on the cooler parts of the chamer (intake valve usually). The fuel injector cleaner you added may have done it's job too well and knock some crud loose from the tank and lines and accumulated on the very very fine screen INSIDE the fuel injectors. This is IF it's running rich.
Your best bet is to pull each injector in turn and fire them up. I've done this on my B21 by putting a rubber stopper in the injector's hole and then starting the engine on three cylinders, with the one I'm testing pointing into a 1 liter Coke bottle. This is NOT a Volvo reccomended procedure and you do so at your own risk. Vaporized gasoline ain't orange juice.
Your mileage really sucks though, so it's possible you have a few different problems.
Michael
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Line Pressure . . . . 64-74psi (pressure coming off the fuel pump)
Rest Pressure . . . . 24-34psi (pressure when fuel pump is off)
Control Pressure . . 50-55psi (pressure to fire injectors)
- When you first pressurize the system, you should hear the injectors "sing". With a fuel pump capable of pumping 26 gal/hr at 70psi, you should make sure that your fuel hosery is in good condition. Small cracks = BIG leaks. Priming the fuel pump when installing it is advisable. When in doubt, replace the high pressure fuel filter (~$18 at IDP). To test system w/o running the engine:
1. Position your fully-charged fire-extinguisher (with safety pin removed) and pressurized garden hose within reach. Evacuate the children and elderly to a safe distance where they can watch any potential fireworks instead of participating in them. Instruct them how to quickly dial 911 should they hear an explosion and see a greasy plume of black smoke where you were standing. In other words, be careful, don't under estimate the explosivness of gasoline. And Sven 'Crispy' Bjorgensenn advises "DON'T PRIME THE MANIFOLD WITH RAW GAS".
2. Turn on the ignition
3. Remove the ignition and prop up the Air Flow Sensor Plate. (Someone mentioned a way to do this by removing one of the little electrical connections in the system, but I haven't tried it yet.)
a. If the system pressurizes, you should hear the injectors sing.
b. If the Fuel pump is working, you should be able to go to the back of the car and hear it running.
c. If fuel pump is running, but no gas is coming out, work your way upstream from the injectors. Two easy places to check for fuel flow are, first on the backside of the injector and second on the upstream side of the fuel filter.
/\ Lawrence Buja Climate and Global Dynamics Division
\_][ southern@ncar.ucar.edu National Center for Atmospheric Research
\_________________________Boulder,_Colorado___80307-3000__________
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Date: Mon, 17 Feb 1992 22:17:06 -0600 From: Juan Moran <moran@uxh.cso.uiuc.edu>
I have had the last few days problems withe fuel injection of my 1975 245 Volvo. The sympotms were that the car just did not want to accelerate and backfired. It would if idle but in periodic surges. When I would engage it in first gear it just would not accelearte. It would forward with it own surging type of fuel functioning.
(I have a '75 244, and once and a while I see it behave similarly, particularly when the weather is very cold, but I suspect that your problem is more severe.)
I checked some things starting from the fuel pump all the way forward to the injectors. This is what I have found:
1.) The fuel pump had a type of rubber attachement which was eaten up and disintegrated by the gasoline. The fuel pump had pretty much burned up because it was blcoked by the gunk from the rubber. The rubber was in the fuel tank and there still some peices in the tank.
Yuck. Disolving things in the fuel tank are bad. There is a fuel filter in the tank which should catch big things, and you can change it I think by unscrewing a plug from the bottom of the fuel tank. If there is something in the tank, that filter might be clogged. I hope for your sake that said crud did not make its way past the main fuel filter, because if it's gummed up your distributor and injectors, you're up a financial creek.
2.) I did not quite check the fuel accumalator as I do not know how to check it. I thought of just replacing it now.
Don't bother. The accumulator is just a diaphragm which holds the pressure in the fuel lines when the engine stops running. It makes the car a little easier to start, but I drove without one for a few years without any trouble. As long as it doesn't leak....
3.) After putting another a good used fuel pump, I checked the pressure at the hose coming from the fuel pump to the fuel filter. There was quite a squirt when I loosened the nut/bolt. So I think the pressure was fine at that point.
4.) I check in the same way as above the fuel pressure from the fuel filter to the fuel distrubutor. There was quite a squirt there too.
The pressure should be somewhere around 60 PSI (a Haynes manual will tell you all of this), and anything in the ballpark is going to give "quite a squirt."
5.) Next I checked the fuel injectors at the hose level. That is I unscrewed the hose from the injector. There was a 1-2 drops of fuel coming out at all 4 hoses. To me that indicated no pressure was coming from the fuel distributor to the injectors.
You can check whether the injectors are clogged or corroded by lifting the plunger plate a bit while the ignition is on but the engine is not running. This will turn on the fuel pump and send fuel through the injectors. They should spray nicely in a circle. If they dribble, it's time to clean or replace them. (I've no experience cleaning injectors.)
7.) I next checked the fuel pressure going the distributor to the warm-up regulator. When I loosened the bolt, there was a good squirt and the engine seems to idle faster but without getting rid of the periodic surges.
That loostening might have changed the fuel pressure and altered the mixture. In any case, you're going to need some "special tools" to check the pressure in a more quantitative manner.
My advice: was the "rubber attachment" the hose between the tank and the pump? If that's it, then it might be that your tank filter is not clogged and your main fuel filter is clogged. (The main filter should get replaced every 20 thousand miles or so anyway.) Replace the main filter, check the injectors, and hope that nothing else was clogged.
-dg
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On Jun 22, 4:25pm, "Y. Alan Wang" writes:
> When I first got my new 84 245, it takes me no time to know I have to put
> premium 92 octane fuel.
> I found one condition (where) it still pings(,) which
> is after picking up speed between 40 and 50, loose up the gas pedal
> and apply it lightly to maintain the speed. IT PINGS.
> Anyone can explain? If I put the gas padel a little bit harder, no ping.
Pinging is caused by uneven combustion in one or more cylinders. Generally the is caused by a "hot spot," something like a carbon deposit in older engines or just the residual heat of the spark plug electrode. Pinging gets worse when the "octane number," an indication of the resistance of the fuel to resist spontaneous combustion, is insufficient for the conditions at hand.
Advanced (early) spark, warm weather, previous "pinging," higher effective compression ratios (either the static compression ratio of the motor, or due to manifold vacuum) tend to make the motor run hotter.
The spark advance is, in part, controlled by the engine manifold vacuum. At light load, the vacuum is high, advancing the spark more. Under these circumstances, your motor "pings." By depressing the pedal slightly more, the manifold vacuum drops, and the spark is advanced less. In your case this will eliminate the pinging.
I would suggest trying the next cooler heat-range spark plug if this is a persistant problem as a start.
BTW : my v6, which does not have much of a pinging problem, pings at high rpm (over 4000rpm, under high engine load on warm days). In other words, if I want to cruise the Macdonald-Cartier southwest of Toronto on a warm, summer day at prevailing speeds (80+ mph), I had better fill up with with 89 octane!
tim
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All here should take note of one of the latest tech tips in the recent IPD newsletter. It deals with the 25 amp fuel-injection fuse under the hood near the battery. The fuse, fuse terminals and the holder can deteriorate and cause many problems, including stalling, hard starting, stumble, and no start. This fuse protects several relays and other system components. They advise looking for discolored fuse terminals and melted areas of the holder caused by overheating. They also advise checking the metal areas of the holder which hold the fuse spades for signs that they have spread and can no longer hold the fuse tightly.
This fuse and holder can cause so many strange problems (and apparently-is- causing them quite frequently) that according to the text of the article, Volvo is now advising that the fuse and holder be changed during the major service intervals.
Another tip sent in by an owner was related: His car was stalling out under accelleration and then would cut in again and run fine. He traced the problem to the lead for this fuse at the positive battery post. Although the connection to the post was fine and tight, the bolt and nut had built up corrosion which prevented the fuse from getting full 12 volts. THis was causing the problems. Clean this bolt, bolt head and nut. He actually replaced his with stainless and added a lockwasher. The problems disappeared.
-_Chris
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Here is a table of the various fuel injection systems (including carbs) over the years. I lifted this from the 'Volvo Problem Solver' manual, advanced edition. Am I violating any copyright laws by regurgitating facts from a copyrighted book?
****************************************************************************************************************************************************************** START TABLE ***********************************
**********************************************************************
4 CYLINDER
YEAR | BODY | ENGINE | FUEL | IGNITION ----------------------------------------------------------------------- 1962-66 | 444,544,122 | B14,16,18 | CARB | POINTS| 130,1800 | | | ----------------------------------------------------------------------- 1967-68 | 122,140,1800 | B18 | CARB | POINTS ----------------------------------------------------------------------- 1969-73 | 140,1800 | B20 | CARB | POINTS ----------------------------------------------------------------------- 1970-73 | 140,1800 | B20 | D-JET | POINTS ----------------------------------------------------------------------- 1974 | 140 | B20 | K-JET | BOSCH POINTLESS ----------------------------------------------------------------------- 1975 | 240 | B20 | K-JET | BOSCH POINTLESS ----------------------------------------------------------------------- 1976-81 | 240 | B21 | K-JET | BOSCH POINTLESS ----------------------------------------------------------------------- 1981-82 | 240 | B21 | K-JET | MPG COMPUTER ----------------------------------------------------------------------- 1983-84 | 240 | B23 | LH INJ | MPG COMPUTER ----------------------------------------------------------------------- 1985-88 | 240 | B230 | LH INJ | MPG COMPUTER ----------------------------------------------------------------------- 1989-on | 240 | B230 | LH INJ | EZK COMPUTER ----------------------------------------------------------------------- 1981-85 | 240 | B21TURBO | K-JET | BOSCH POINTLESS ----------------------------------------------------------------------- 1984 | 700 | B23TURBO | LH INJ | EZK COMPUTER ----------------------------------------------------------------------- 1985-on | 740 | B230 | LH INJ | EZK COMPUTER ----------------------------------------------------------------------- 1985-on | 700,900 | B230TURBO | LH INJ | EZK COMPUTER ----------------------------------------------------------------------- 6 CYLINDER ----------------------------------------------------------------------- 1969-72 | 164 | B30 | CARB | POINTS ----------------------------------------------------------------------- 1973-75 | 164 | B30 | D-JET | BOSCH POINTLESS ----------------------------------------------------------------------- 1976-79 | 260 | B27 | K-JET | BOSCH POINTLESS ----------------------------------------------------------------------- 1980-82 | 260 | B28 | K-JET | BOSCH POINTLESS ----------------------------------------------------------------------- 1983-86 | 760 | B28 | K-JET | BOSCH POINTLESS ----------------------------------------------------------------------- 1987-90 | 760 | B280 | LH INJ | EZK COMPUTER ----------------------------------------------------------------------- DIESEL ----------------------------------------------------------------------- 1980-85 | 200 | D24 | DIESEL | ----------------------------------------------------------------------- 1983-86 | 700 | D24TURBO | DIESEL | -----------------------------------------------------------------------
********************** END TABLE *************************************
**********************************************************************
While typing this table into the computer, I started wondering about the following two 1800 specifications:
1969-73 | 140,1800 | B20 | CARB | POINTS 1970-73 | 140,1800 | B20 | D-JET | POINTS
I was under the impression that in 1970, all 1800's became fuel injected, whereas one can see that the table indicates that there are both carb and fuel injected for those last four years. Is this a mistake in the table or were there really carbureted 1800's in the 70's ?
Pete
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Hi,
1) 1800 designations - From my readings, the 1800's history of designations went something like:
P1800 - original 1800 made in England1800S - 1800 production moved to Sweden
1800E - fuel injection added
1800ES - fuel injection wagon
The argument I'm in the middle now with some friends is whether my '70 1800E is an 1800E or a P1800E (with the 'P' prefix). I believe that it's just 1800E but I don't know for sure.
The following is longer that I expected (in retrospect) and pertains to an '83 245T with the K type fuel injection.
2) Fuel Injector Story - The last several months I've been noticing a slight but steady decrease in my gas mileage. I checked all the usual things and I had just tuned it this past fall so I attributed it to oxygenated fuel (although I don't know if the gas I buy is, in fact, oxygenated). Then some symptoms developed that indicated it was definitely not the fuel: poor idling, hesitating on acceleration for a second, but, strangely, at highway speeds, one wouldn't know that there was anything wrong.
So I started diagnosing by removing one spark plug wire boot at a time while the car was idling. As each spark plug was disconnected, the engine would run more roughly as one would expect, except for cylinder #3. Disconnecting it's spark plug made no difference in the idle. Ha! I'm on to something now!
I determined that the problem wasn't with the ignition by swapping spark plug wires, spark plugs, and checking the distributor. So, then I started to investigate the fuel injection.
Now the cool part that I had never done before. I removed each fuel injector and stuck each into the mouth of a clear 1 liter soda bottle (after drinking all the soda). Then I ran the fuel pump by jumping fuse #5 to #7. Finally, I controlled the air metering plate (is this the correct term for the thing?) by sticking a 3 mm allen wrench into the air/fuel ratio adjustment screw. This causes the fuel injectors to spray at different rates depending on the position of tha air meter plate.
Lo and behold, injector #3 at low rates squirted in a straight stream unlike the other 3 which still made a nice mist. At high rates, all the injectors sprayed nicely, which would explain why at highway speeds everything worked fine.
I ordered four new injectors from Auto Show Volvo in Seekonk, MA. These guys are really friendly and helpful and their 25% of list is about the best discount I've found. They also throw in free gifts with your purchases such as T-shirts. I HIGHLY recomend them.
The installation of the injectors is easy except that the seals tend to be quite tight. My Volvo Problem Solver book said to really coat all the parts with alot of silicon spray, which I did. After getting everything back together, the car started fine. It idled nicely but it still hesitated upon acceleration. I way bummed out at first but after driving it about 5 miles, the hesitating went away. I'm guessing that it took some time for the residual silicon to be flushed out of the system. I haven't put enough miles on the car yet to see if my mileage has returned to normal.
I've seen several people say that this oxygenated fuel will loosen particles in the fuel system causing clogged fuel filters and injectors. I have to wonder if this was what caused my problem or at 138K it was natural wear and tear.
Pete
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I've spent the last couple of weekends checking out the lambda-sond system on my 80 240. I've used the Volvo problem solver from IPD and Bentley's guide to Bosch FI, each of which gives a different set of tests. I've concluded that the computer is bad. I thought I'd pass along a description of the diagnostic tests in case anyone else had comments. Does anyone know where I could get a used FI computer for an 80? (New ones cost more than $400...)
There are two ways to test the lambda-sond system - by testing the voltage from the O2 sensor and by testing the duty cycle of the frequency valve:
Voltage Tests (from the Volvo problem solver): voltage from the sensor ranges from 0-1 volts, with values near 1 indicating a rich mixture and values near 0 indicating a lean mixture. Readings are valid only when the engine is fully warmed up. Voltage should be around .5v. If the voltage is cycles slowly from low to high (or if there is no voltage at all), the sensor is probably bad. If the voltage is steady but too high or low, try adjusting the mixture.
My car: voltage was consistenly high, around .8v, and adjusting the mixture has no effect until the mixture is set so lean that the car won't run.
Duty Cycle Tests (from the Bosch FI book): duty cycle is tested with a dwell meter at a special pick up wire (in my case, it's a red wire that comes out near the battery.) A high duty cycle indicates that the frequency valve is richening the mixture, a low one shows that it is trying to lean it out. Normal duty cycle should be 45-55 degrees. The actual duty cycle is higher than the dwell reading, since dwell is measured 0-90 degrees, while the duty cycle is measured 0-100. Disconnect the lambda sond from the computer (this puts the engine in open loop mode - the computer sets the duty cycle to a pre-determined value.) The duty cycle should be about 45.
My car: open-loop dwell is 64 (so the duty cycle is even higher.) It makes sense that the O2 sensor is reporting a consistently rich mixture.
Now ground the green wire that runs to the computer against the engine. This simulates a lean mixture and should cause the duty cycle to increase to 95 (in an attempt to richen the mixture.)
My car: passes this test.
Now take a 2V battery, connect the green wire to the + terminal and ground the - terminal to the engine. This should simulate an overly-rich mixture and cause the duty cycle to drop to 10 or so.
My car: doesn't respond to the battery (but I used only a 1.5V battery - but it tested out a full 1.5 volts on my voltometer.) All the wires to and from the computer test out ok (i.e. no shorts.) However, if I reconnect the lambda-sond and let the car warm up, it settles into a duty cycle of about 25. (This amounts to a consistent, ineffective, attempt to lean out the mixture.)
Conclusion: the incorrect open-loop duty cycle can only be the fault of the computer, so I need a new one. Conclusion: the incorrect open-loop duty cycle can only be the fault of the computer, so I need a new one. The computer seems to sometimes respond to an overly-rich mixture, but other times not. The lambda-sond is correctly reporting the overly rich mixture, so it's probably not bad. The general problem is that the car runs rich till I lean out the mixture so much that it won't run at all.
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To check and see if the line pressure is being lost during the time between shutting down and the next restart;
turn the key on......the pump will run briefly (several seconds on a timer) this is to give a brief pumpin up of the fuel pressure.
turn the key off.
repeat this several times.
If you note a difference in the sound of the pump prior to it timing out this is an indication that the pressure has come up to snuff. ( the pump feels the resistance to flow of fuel when the pressure is up and no flow is going to the engine).
now try to start the car.......if it starts first time this is an indication that you have manually built up the pressure in the line by the key on off routine..........problem the fuel pressure is bleeding off during periods of not running. check for one way valves in the fuel supply system...it may be leaking internally hence the loss of standby pressure.
Darryl
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