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Long time reader, first time poster. Just picked up a 1991 240 with an automatic tranny and the B230F engine. Car runs great at speed, but the engine shakes pretty good at idle. Observations and work done so far:
* With engine running, pulling the spark plug wire on cylinders 1-3 significantly changes engine speed/sound.
* With engine running, pulling the spark plug wire on cylinder 4 *does not* change engine speed/sound.
* Replaced all four spark plugs, but this did not result in any engine behavior changes.
* Wires are Bougicord brand, and free of visible cracks or abrasions. Did a poor-man's test on all four wires ... with the engine running, pulled each wire and placed a screwdriver near the plug end of the wire, verified that a spark jumped from each to the screwdriver.
Searching around, I found this thread:
240 SE rough idle
This is pretty similar to my situation. I did not see a resolution on that thread.
Recommendations? I've seen suggestions such as:
* Replace spark plug wires
* Replace distributor cap
* Replace distributor rotor
* Do a compression test
I'm not much of an engine mechanic, but am willing to try things. Is the cylinder not getting spark? Not getting fuel? I can replace parts all day, but there's no point in replacing good parts with new ones just for the heck of it.
BTW, the old plugs on this thing weren't in bad shape ... but was surprised that the were Volvo-branded plugs. Wonder if they'd ever been changed? 136K miles on the car.
This is my first 240. Love it so far, even with this particular engine challenge!
Thanks in advance!
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Thanks for the update.
Do you know the amount of torque for the eight nuts that attach the intake manifold to the engine head? --- Thanks!
I replaced my original 1990 intake manifold gasket over the weekend with a Genuine Volvo intake gasket. The original gasket was very brittle and seemed to be soaked with gasoline, however, it did not appear to have any issues.
I was surprised that this job did not take as long as I thought it would take, only about 45 minutes. I did have to trim the back part of the gasket so that it would fit correctly.
The replacement gasket did not seem to make any difference, my engine still runs a little rough, but not as rough as yours does in the video.
--
If it needs to be maintained, repaired or replaced on a 1990 240, I've probably done it. '90 240DL, 292K looking forward to 300K badge (or sticker??). >>You haven't really worked on a car until you draw blood<< :-}
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> Do you know the amount of torque for the eight nuts that attach the intake manifold to the engine head?
No, I don't. I went finger-tight, plus maybe a half-turn after that. Wouldn't go much farther anyway.
I agree ... the job does not take very long at all. 90 minutes start-to-finish for me, which included testing the injectors and cleaning the gasket mounting surfaces very well.
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This problem has been solved by replacing the intake manifold gasket. Much thanks to Art, Bruce, and others for their great suggestions.
I've posted a before-and-after video of the engine here. Big difference!
Observations and procedure:
* Engine shaking hard at idle.
* Spark plugs replaced and other ignition parts inspected and/or tested ... all good.
* Cylinders compression tested ... good.
* Injectors tested using OBD-1 mode 3 diagnostics ... good.
* Removed intake manifold and replaced gasket. That solved the problem. The old gasket at cylinder #4 was distorted into a distinctive oblong-oval shape, not round like the other cylinders.
For reference, the replacement part was around $5 at multiple locations. I got mine from http://fcpgroton.com, part # 1378879.
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Have you checked #4 for spark and fuel?
Dan
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> Have you checked #4 for spark and fuel?
I've checked #4 for spark, we're good there. How do I go about checking for fuel?
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If there were no spark you would expect the plug to be wet if you are getting fuel.
Put a screw driver on the injector and up to your temple, do you hear the injector clicking?
If it is clicking you need to take the injector out and see if it is spraying.
Art has a nice pic of the process.
http://www.brickboard.com/RWD/volvo/1442373/220/240/260/280/240_engine_shake_idle.html
Dan
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> Art has a nice pic of the process.
Thanks. i saw the picture, but didn't quite know what I was looking at. I see now that the injectors are removed, and #1 is dumping into a jar. I'll check out the injectors next.
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Update:
I ran a compression test on the engine (B230F). The test was done on a warm (but not hot) engine, with the throttle closed. I missed that step in the process ... this was the first time I've ever done a compression test.
Test results:
#1 : 140 PSI
#2 : 136 PSI
#3 : 141 PSI
#4 : 145 PSI
I understand that these values should be > 128 PSI, and within a close range of each other. Looks good, then?
The guy at the local Autozone (which loaned me the compression test kit) said that if the ignition system was OK and the cylinder pressure was OK then it was probably a bad fuel injector.
Thoughts?
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I'm having the same issue myself. Exactly. Compression good, so I went the fuel injector route. It made no difference.
I'm inclined to go with the intake gasket theory. That's my next step.
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Chuck, did you determine if the intake gasket was the issue on your car?
My injectors are "clicking" (used a stethoscope!). Haven't yet had a chance to pull them to test fuel delivery. But the intake gasket is probably messed up ... it has a nice bubble in it at the problem cylinder. Ordering a new gasket right now ...
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That's a good point Bruce makes. In my case (photo of loose rail) I started with a fresh gasket, so it didn't even cross my thoughts. I've often claimed any original gaskets on 240's are bound to look like this or worse, by now.
--
Art Benstein near Baltimore
My luck is so bad that if I bought a cemetery, people would stop dying. - Ed Furgol
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1993 240
235000 miles
I've been chasing a shaking engine at idle. It started getting pretty bad a few months back, and this thread pointed to something I had not considered - the intake manifold gasket.
So I just wanted to say thank you! I replaced the intake gasket this weekend with a Genuine Volvo part, and the engine is SO MUCH smoother, and there is no shaking whatsoever. Pickup even feels better, but that could just be my projection.
I've added a few pics to the gallery, including the gasket which was letting in unregulated air in at least one of the cylinders.
This forum is priceless!
Thank you!
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I have seen a bad intake manifold gasket cause severe idling shakes.
In this case it was for cylinder #1, and the gasket actually looked like it had blown outward around the edge of the intake port. I have never seen a bad injector.
--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.
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It is likely the sparkplugs will not be evenly colored if you have an intake leak.
Last I had this problem, the front 3 plugs were blacker than the 4th. The computer was compensating for the air leak by running the engine richer, which resulted in sooty plugs, except for #4, which looked cleaner. Of course it was getting the unmetered air coming in around the broken intake gasket.
Take a careful look at the plugs again.
Replacing the gasket is cheap and not too laborious.
--
84 242Ti IPD bars&springs, 89 745 16v M46 IPD bars, 89 744 16v M46 IPD bars, 93 945 Turbo AW71, 91 245SE AW70 IPD bars, 93 245 CLassic M47
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did you try the old trick of spraying the plug wires with a mister and looking for arcing. in the shade or at night. seems simple and you can steal your wifes water bottle she uses for her hair
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Yep, tried that. No arcing. Ignition seems electrically sound, from coil to spark plugs.
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You always have to wonder why the previous owner sold the car. Why she really sold it.
Sounds like you don't mind diving in if you are brave enough to yank plug wires while the motor is running. And it sounds like cyl 4 is a suspect. Here would be (and has been) my approach:
1) Do a compression check. Make sure cyl 4 hasn't dropped a valve seat.
2) Be sure the injector for #4 is working. If you look up the 7/9 FAQs you can learn to use the mode 3 diagnostics provided by OBD-1. With them you can pulse the injectors. If you hear it clicking OK, the next step would be to see if it is clogged by swapping it to another location, or squirting it into a jar.
--
Art Benstein near Baltimore
While driving yesterday I saw a banana peel in the road and instinctively swerved to avoid it...thanks Mario Kart.
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One other cheep check - pop the distributer cap to see if there is any "scratch" marks inside the cap. this is a sign of the fire arcing. If you see this, or if the tip on the rotor button is pretty pitted - I'd replace.
(sometimes it's the little obvious things that we end up spending the most time on!)
Best of luck with your new 240 -
Hope that helps
Charles
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Thanks for the suggestion. I just pulled off the distributor cap, and inspected the inside of the cap and the rotor. Both look perfect ... too bad I couldn't fix this problem with cap/rotor replacement!
On to the compression check this evening.
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Thanks for the quick reply, Art. I'll try the compression check first.
The car was cheap enough, in great cosmetic condition, and is a project car for my son. It's almost a good thing that's it's not perfect, otherwise he (and I) wouldn't have to learn anything. :)
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posted by
someone claiming to be tom
on
Thu Sep 16 10:50 CST 2010 [ RELATED]
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I did not have the answer for your question, but I like to know how did you pull the sparkplug wires, with the engine running? I tried, but I got zapped, and I quit doing it, after that. And yes, my 240 also shakes a bit at idle.
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> how did you pull the sparkplug wires, with the engine running? I tried, but I got zapped
I did not get zapped. Which means that I was sufficiently insulated from the current by my good wires and/or good rubber gloves. Consider wearing rubber gloves, perhaps?
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