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Having loads of fun trying to figure out the rough idle on my 90 240 4cyl.
It started running rough at idle 2 weeks ago. I have replaced spark plugs/ignition wires/cap/rotor and cleaned the idle motor and the AMM (with carb cleaner). I put new seals on all the injectors and it still has a missfire during idle and even misses slightly when I increase the idle speed. It seems to run fine at hiway speeds. Where should I direct my trouble shooting? There are no error codes at all. THANKS
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Update to rough idle...
Finally got around to taking out the idle motor and giving it a good cleaning and a quick spray with WD40. It now starts up fine (cold) goes into a slightly raised idle for a few secs and then settles down to what would be a normal idle. Except that there is shaking and I hear slight mis-fires going on, like pop....pop..pop....pop..pop..pop...... and so on. If I raise the engine speed it seems to clear up, but there is some missing going on still. It almost seems like I have a faulty plug or maybe the plug gap is too wide? These Nippon-Densu plugs were installed about 2 weeks ago. Where should I go from here???? Thanks!!!!!!!!!
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posted by
someone claiming to be VolVolina
on
Tue Oct 5 07:21 CST 2004 [ RELATED]
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I also have a 1990 244DL. I went through searching for cures for my rough idle troubles. Here's a list of what cured it.
1: New control arm bushings. One was so shot that the rubber was completly separated from the rubber. Putting new bushings in helped a significant amount of vibration.
2: new Crank Position sensor. This REALLY made the most important difference. I think they're known to be bad if they have a yellow band around the cable near the plug
3: Cleaning out the hose and nipple from the intake manifold to the flame trap. That very thin hose was clogged and spraying it out smoothed out the idle quite a bit.
Hope that helps.
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The crank position sensor, is this the item sitting way to the back of the engine sitting on the bell housing for the trans? If so, how in the world can one replace/test/get to this thing? Thanks~
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From the right side, using left hand blind (after first sighting location) to work a 10mm wrench on the single mounting bolt.
Check the 700/900 FAQ (same b230 engine) for more details.
--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.
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#3 If left undiscovered, also causes flame trap issues and engine seal leaks.
If in doubt, replace the hose (about .60) and clean out the nipple in the intake.
Ask me how I know about this...
--
Jim 90 244DL 243K
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The flame trap has been replaced and recently checked. As a side issue, if I unplug the O2 sensor on a normally good volvo 240, what should the symptoms be other than a code being set? Mine seems to not make a difference connected or disconnected.......
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Can't answer your question on the O2 sensor, I've never had an issue with mine. Check the 700/900 FAQ or do a search, I think there is plenty here in the archives on the O2 sensor. Or post another question...
IMHO - My money is still on a dirty throttle body.
--
Jim 90 244DL 243K
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posted by
someone claiming to be jimmy volvo
on
Tue Oct 5 07:18 CST 2004 [ RELATED]
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JBR,
I HAD THE SAME PROBLEM AND ALSO DID A COMPLETE TUNE UP,, FINALLY SPRAYED THE INTAKE MANIFOLD GASKET WITH CARB.CLEANER AND IT SMOOTHED RIGHT OUT,, AFTER A NEW GASKET WAS INSTALLED,, SHE RUNS SMOOTH AS SILK
JIMMY VOLVO
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posted by
someone claiming to be 240snowmobile
on
Tue Oct 5 06:42 CST 2004 [ RELATED]
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Does your idle improve when the AMM is disconnected? Also, if you squeeze one of the hoses to/from the IAC, does the engine speed drop like it should?
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Dumb question, but what is the IAC?
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Same as the idle motor, I believe. IAC = Idle Air Control???
Jim 90 244DL 243K
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If I disconnect the AMM it goes into a higher idle, but it is still missing (seems like a sort of pop mixed in with the normal engine noise). It sets the code for faulty AMM and I have to clear it out again. I tried driving it with the AMM disconnected, but it did not run smoothly like it should. It runs lots better with it plugged in.
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A couple of no/low cost possibilities:
Have you tried cleaning the throttle body? That seems to be the usual culprit.
It wouldn't hurt to clean all engine grounds, fuses and the fusebox. Replace any worn out parts. I may be hallucinating, but my car seemed to idle better after that....
--
Jim 90 244DL 243K
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Throttle body, O2 sensor...I'm having the same issue(s) with my '92. New plugs/wires/cap/rotor but have yet to clean the throttle body, idle motor, and AMM. My 02 sensor is pretty new as well. Runs fine at higher rpms (highway, daily driving) but at lights/stops the car def shakes. It might be because I have a more aggressive cam which is inherent of a slightly rougher idle but it has gotten worse over the past few weeks.
Best,
Adam
--
'92 244GL silver-metallic, 150k, Enem V15 cam, Bilstein HDs, IPD sways, upper+lower braces, Cherry-Turbo strut brace, 240 OEM rear spoiler, 15' Dracos, E-codes w/side repeaters, Euro cowl covers paint-matched, Magnaflow 2.5' SS exhaust w/Unitek header
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Is it possible to clean the idle motor and throttle body? If so, please post instructions as I'm having same problem.
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Sorry, I didn't mean throttle body. I've done that before. I meant the air mass meter. I'd be afraid to try it.
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Cleaning the idle motor simply requires taking it out, spraying it with carb cleaner, making sure nothing is still sticking (manually spin it a few times) and after it drys add a little WD40 (I think that is what I added) and it went from too high of (uncontrollable) idle back to normal. However I have no idea how to clean properly the throttle body.
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IPD sells a kit to clean the throttle body and has instructions.
Click Here for PDF
--
'92 244GL silver-metallic, 150k, Enem V15 cam, Bilstein HDs, IPD sways, upper+lower braces, Cherry-Turbo strut brace, 240 OEM rear spoiler, 15' Dracos, E-codes w/side repeaters, Euro cowl covers paint-matched, Magnaflow 2.5' SS exhaust w/Unitek header
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I'll sell you a throttle body cleaning kit and throw in a bridge besides.
Seriously, just get some carb cleaner, a new TB gasket, and a clean rag. Be careful not to spray the throttle position switch mounted on the side.
You actually cleaned the AMM with carb cleaner? Yikes, that sounds pretty dicey to me. I wouldn't do that if I were you. I think that could only do harm, and it won't help any.
You could still have a bad AMM, and a different problem besides causing the poor idle. If you had a known good AMM to swap that would be ideal, but as things stand I would recommend continuing to eliminate the usual suspects for poor idling, starting with the TB, spark plugs/wires, dist. cap/rotor, and throttle position sensor if you have one.
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Read on another site that a few people have been doing this for years and it works fine. One guy said he gently used a q-tip on the wire. Although I wonder if that is asking for trouble or not.
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