posted by
someone claiming to be rickf
on
Thu Dec 30 18:28 CST 2004 [ RELATED]
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I got this 1980 240 DL for $325, drove it nearly 6 years with no troubles.
It now runs on only 3 cylinders. It has adequate (not great) compression, it has 175 PSI in two holes and 150 PSI in other two. Has decent spark. Conclusion is it must be fuel supply. Even on only 3 cyls, the car starts easy, just a flick of the key.
To determine which cyl was bad, I pulled 1 plug wire at a time to see when engine running changed. It was so rough (at idle) I couldn't really tell. So I went the other way, and put on only one plug wire at a time. It would start and idle on 1, 3, and 4 (actually, I was surprised it really would run at all on one cyl.)
So, it looks like #2 is the culprit. The injector nozzle seemed the most obvious culprit. I went to the u-pull-it, found a similar model that was clearly there because of a crash (and therefore was likely a running car) and pulled all the injectors. Swapping in these injectors made no difference.
In retrospect, what is probably a related symptom is that over the last year or so, the car began pinging a bit. Not much, and I attributed it to crappy modern gasoline. Now I'm thinking that one hole (or maybe more) was gradually getting lean and causing the problem.
So, the problem must be deeper in the injection system. Anyone seen anything like this before? What am I looking for?
-rcf
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Hello Rickf,
Don't know if this'll help you or not. I've never really messed with this system on the volvo. I did however have a simular problem on a VW rabbit years ago.
In my case a small portion of the injector hose had broken loose and lodged in the fitting. If I remember correctly (certainly not a pro on the matter), Volvo used hard lines though. Worth a check maybe, dunno.
I'd go for the pattern / flow method shown earlier. (which is what we did)
After a couple weeks of the car sitting while I tried to come up with ideas, I decided to just trace the system back to the cause of low flow. When I removed the injector hoses to try the flow test through just the hoses (no injectors), the culprit dislodged and suddenly they were all flowing the same. Put the hoses back on and it ran like a champ. Yanked a JY hose and replaced the one I had trouble with. Drove the car 2 more years b4 getting too annoyed with the car's lack of a trunk and the ride. Sold it to my brother who's still driving it 2 transmissions and 12 yrs later with the same junk yard hose.
Like I said, I have NO idea if this will help you, but perhaps.
Best of luck,
Frank
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posted by
someone claiming to be Manolo
on
Thu Dec 30 20:20 CST 2004 [ RELATED]
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If a different injector made no impact, then you need to check the electrical pulses to that injector. If the problem is electrical, it is most likely the wire or connector.
Have you considered the possibliy of carbon buildup on the exhaust valve? That would be consistant with the symptoms you are seeing.
I take it that the car runs on 3 all the time, not just at idle, right?
One last thought - remember that it is harder to fire a plug in the hole than it is to jump a spark in ambient air. Check under the distributor cap for cracks and carbon tracks.
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This model has mechanical fuel injection, I think 1980 is the last year for that. There is no electrical connection at the injector, just the fuel hose from the "fuel distributor". So, unless I have made a mistake elsewhere, it would seem the problem is in that fuel distributor. What is in there? What can go wrong? Some valving? Any filters? Maybe just dirt clog?
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You might want to check compression before you get too far in the injection system. You might have a burnt valve. Remember you need three things to have ignition- spark, fuel and compression. An easy trick for the injection and spark is to switch the wire and injectors. If the problem does not move the the other cylinder- check for valve or piston problems. good luck
Mike
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I did a compressino test, this was mentinoed in the original post. But since that post was so long, I can understand not noticing it.
It has 175 PSI in two cylinders and 150 PSI in other two. 150 isn't great, but is enough to run.
It does happen to be one of the 150 PSI cyls that doesn't run, but the other 150 PSI cyl is running.
Given the three necessary things, I have adequate compression, I see a spark, and so I suspect fuel. I have swapped plug wires and injector with a running cyl, and that running cyl stayed running, the non-running stayed non-running.
So a new question: Is it possible for the fuel system to fail on only one cylinder like this? Or does it tend to be all or nothing?
-rcf
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The K-Jet mechanical fuel injection was used into the 80's on some cars.
I've never taken apart the fuel distributor. Did you test the spray volume and pattern of the injectors? If you think it's a fuel problem, it might be something to consider doing. Bentley says that if you get bad volume or a bad pattern with one injector, swap injectors with another cylinder, and try again. If the same injector is bad when it's on a different cylinder, it's probably the injector. If the same cylinder is bad with a an injector that worked a minute ago on a different cylinder, then the likely suspect is the fuel distributor.
To run the pumps without the engine, jump #87 (or 87/2) and #30 terminals on the fuel relay plug. (We made a swiched jumper and hung it on the blinker switch during the test so we could turn the pumps on and off easily.) First remove the bellows below the throttle body. Lift the air sensor plate by grabbing the center nut with pliers to run the injectors. We taped four beer bottles to a board to use as fuel measuring devices. Run the pumps at various speeds and watch the injectors carefully. We filled the bottles about 1/3 full, then stood them all up to compare volume. Then we pointed all the injectors into a bigger open container and ran the pumps to watch the patterns. Fun test, but much safer with two people. Have lots of ventilation if you do this.
--
Thanks everyone for the advice. 81 242 Brick Off Blocks, Turbo bars and wheels, B21F, M46; 86 244, B230, 148k , auto.
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