M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine + Driveline => Topic started by: iamcreepingdeath on July 08, 2009, 11:47:22 AM
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(I posted this a long time ago, and i still have this problem.)
Anyway, after the last autocross meet, my car developed a funny idle. When i start the car cold, it idles super rough and low like it has some wicked cams, and then stalls out. After the car warms up, it idles fine, but a bit high at 1000 rpms, which i figure i can fix by just adjusting the idle.
I did some forum searching, and it seems the cure-all is to clean the ICV. Now please forgive my ignorance, but where is the ICV valve, and to clean it do i just kill it with some brake cleaner?
I already fixed two vacuum hose issues and no change in the idle problem.
Second question of curiosity is as i was taking the intake boot apart to find vacuum leaks, i discovered a whole LOT of grime buildup on the inside of the boot and in the throttle body. Its like a dirt and oil mix, not goopy or wet, just dryish and caked. What in the world would be causing this?
Thank you guys so much for your help.
-SAm
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The ICV is mounted below the rear of the intake manifold, close to the firewall. On the e30 it sits on a vac pipe that connects to the rear of the upper intake.
Clean it with TB or carb cleaner, no immersion.
All of us with vac leaks have gunk built up all over the place. I'm told that it's due to dino oil and leaks building up all that grime. The intake pulls oil back and mixes with air from vac leaks, causing that crud to build up. I'd figure all three are related. You might want to consider the 'vacuum hose delete' mod detailed on this board in many threads.
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Sam,
The ICU is located just to the right of your intake manifold, as you stand on the drivers side of the engine, and is tucked in a little. You should have little trouble getting it off and out to clean. Get yourself some good carb cleaner and flush it out and let dry. Site will not let me post my pics of mine but there is a pic of it in the following thread.
The gunk you are asking about is commonly found in all of our cars. Here is a post that addresses it and an idea on how to try and remedy the issue of its build up. ( there is also reference to the ICU in this post so look for some more pics of it in the post as you read through it )
http://www.m42club.com/forums/showthread.php?t=2742&highlight=Reservoir
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thanks so much guys.
A vac hose delete?? how is that possible? i guess a little more searching is in order....
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just glanced through the above linked thread, that is definitely something i am going to do!
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NOW WHAT??
So i cleaned my ICV, found tons of cracked hoses and because of a time and money limitations i fixed them with hose clamps and liquid gasket, and got the ol' M42 back into service.
NOW, when i start the car COLD, the idle is super low and the motor stalls right away. To keep it alive i have to keep revving it, and then quickly jump into the engine bay and adjust the idle to keep the engine running.
Then after i drive the car and it gets warm, the idle becomes higher, and so then i go back into the engine bay and lower the idle back down to normal.
If i let the car cool for several hours and then restart the car, super low idle again and instant stall-out without revving the engine.
WTF is up with this??? should i go ahead and do the vacuum hose delete mod? do you think this will solve it? Thanks so much guys!!!
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My next move would be to try and revisit that ICV and give it a closer look again. I will look into and see if there is anything else you could be looking for or doing.
Frank
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I've been having the same problem, idle wise with me mine for a little bit. Only thing I did was use some of my old vacuum hose that didn't look cracked for the delete mod. I plan on just changing it ALL so I know it's new. But when mine's cold, it idles normal, as it warms, rises up to about 1200.
See what it does when you turn the A/C on, does the idle drop back down to about normal? I know when mine's fully warm and idling at 1200, if I turn the A/C on, it drops down to normal idle at 850.
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My next move would be to try and revisit that ICV and give it a closer look again. I will look into and see if there is anything else you could be looking for or doing.
Frank
what would i do ro revisit the ICV? i just sprayed in ALOT of brake cleaner and WD-40 to re-lubricate it. Is this bad? can i actually take the ICV apart?
I've been having the same problem, idle wise with me mine for a little bit. Only thing I did was use some of my old vacuum hose that didn't look cracked for the delete mod. I plan on just changing it ALL so I know it's new. But when mine's cold, it idles normal, as it warms, rises up to about 1200.
See what it does when you turn the A/C on, does the idle drop back down to about normal? I know when mine's fully warm and idling at 1200, if I turn the A/C on, it drops down to normal idle at 850.
my AC doesn't work. Its not even hooked up.
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EDIT: So anyway i did the vacuum hose delete mod successfully.
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No vacuum leaks, i did the delete, and cleaned all the gunk.
BUT, my car will stall out at an idle when cold, and when warm, it idles fine on the high side. Do i need a new ICV?
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bumpity bump bump
My car will barely run when cold, i have to hold the revs with the throttle to keep it running until it warms up. What can be the problem???
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for some odd reason i'd look at the FPR... remove the tiny vacuum hose and see what happens. by removing it, you are causing a rich fuel situation. if you can find something that can create a small vacuum and plug it on there, it will cause a lean situation. If one out your injectors is leaking, you'de have too much fuel for the amount of air and that could cause rough idle/ stall.
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but it only happens when the car is cold, and much worse in colder weather when the car is cold.
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i'm guessing that if your O2 sensor can't see the extra fuel, the ECU will just dump some more in... just a thought
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so do you think it can be a bad O2 sensor that is doing this?
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i don't think it is, but it can help?? if it's not the sensor itself, it can be the heating element that's not working right for some reason. IIRC, there's a thing you could try... not expecting much of it but someone might catch on to the info you give back. in the did we ever figure out the hot start thread (stickied), they talk about a wire that tells the ECU if it has an O2 sensor (or not). try playing with that wire and see what happens. but don't forget to unplug it after you're done testing...
another thing you can try is to "hotwire" the fuel pump at the fuel pump relay between terminals 87 and 30. on your wire, place a switch and start your car normally (switch on the on position. then shut it down by fuel starvartion. (switch off). let your car sit for a while and then put the switch back on and start the car right away. by doing this, you remove all the pressure in the fuel line and also reduce the possible amount of fuel leaking from your injectors/o-ring.
sry for the novel, hope it helps.
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thanks. Novels are ok. I looked at O2 sensors and they are like $120, so i probably won't be getting one of those.
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you can get a mustang O2 (maybe also a universal one) for about 30$. just need to splice them in. search is your friend
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you can get a mustang O2 (maybe also a universal one) for about 30$. just need to splice them in. search is your friend
awesome!! i didn't know they were interchangeable
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i had some similar idle issues, turned out the hose goin from the icv was collapsing, might wanna check that.
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Usually if you are experiencing cold start issues - but the problem goes way once the vehicle gets to normal operating temps - then you need to replace the coolant temp sensor. If the coolant temp sensor has failed, or is sending out of range data to the DME, the DME does not know how to properly compensate for a cold start condition. Once the vehicle hits normal operating temp, the DME is able to compensate better (air/fuel mixture) and will run in limp mode basically so the car can still be driven.
Since you already pulled and cleaned the ICV and there were no changes as to how the vehicle runs when cold, I would definitely suspect a faulty coolant temp sensor.
As you can see in the link below - there are (2) sensors located on the driver's side of the head. # 6 is the coolant temp SENDER for the temp gauge in the cluster, # 8 is the coolant temp SENSOR and relays engine temp back to the DME. These locations and part descriptions are also confirmed in Section 12 (12-106/2) of the genuine BMW E30 Repair Manual. (#8 in the realoem link below is the one you want to replace):
http://www.realoem.com/bmw/showparts.do?model=AF93&mospid=47305&btnr=11_1505&hg=11&fg=15
Also - you can get decent deals on parts at http://www.rockauto.com - if you need an O2 sensor, just look one up for a 94 Mustang GT (5.0) and you can get a BOSCH universal from rock for under $50... It's easy to install or splice into your existing harness, really a no brainer, just need the time to do it...
If you google "rockauto discount code", you will also be able to find codes that will give you 5% off of your total order. Sure, 5% is not a huge discount, but if you are buying multiple things, it surely helps in the end.
You can purchase almost all needed sensors for the M42 on rockauto as well - some are cheaper than your local auto parts stores and those of some of the online BMW vendors.
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i had some similar idle issues, turned out the hose goin from the icv was collapsing, might wanna check that.
actually my hose from the ICV does collapse because it is so thin-walled, but i sort of fixed that by sliding a smaller and much thicker walled hose into the bigger hose. now this does make the total air way smaller, but at least it keeps it open. Do you think this may cause a problem?
Usually if you are experiencing cold start issues - but the problem goes way once the vehicle gets to normal operating temps - then you need to replace the coolant temp sensor. If the coolant temp sensor has failed, or is sending out of range data to the DME, the DME does not know how to properly compensate for a cold start condition. Once the vehicle hits normal operating temp, the DME is able to compensate better (air/fuel mixture) and will run in limp mode basically so the car can still be driven.
Since you already pulled and cleaned the ICV and there were no changes as to how the vehicle runs when cold, I would definitely suspect a faulty coolant temp sensor.
As you can see in the link below - there are (2) sensors located on the driver's side of the head. # 6 is the coolant temp SENDER for the temp gauge in the cluster, # 8 is the coolant temp SENSOR and relays engine temp back to the DME. These locations and part descriptions are also confirmed in Section 12 (12-106/2) of the genuine BMW E30 Repair Manual. (#8 in the realoem link below is the one you want to replace):
http://www.realoem.com/bmw/showparts.do?model=AF93&mospid=47305&btnr=11_1505&hg=11&fg=15
Also - you can get decent deals on parts at http://www.rockauto.com - if you need an O2 sensor, just look one up for a 94 Mustang GT (5.0) and you can get a BOSCH universal from rock for under $50... It's easy to install or splice into your existing harness, really a no brainer, just need the time to do it...
If you google "rockauto discount code", you will also be able to find codes that will give you 5% off of your total order. Sure, 5% is not a huge discount, but if you are buying multiple things, it surely helps in the end.
You can purchase almost all needed sensors for the M42 on rockauto as well - some are cheaper than your local auto parts stores and those of some of the online BMW vendors.
see its people like you that make these forums so awesome. Yeah i had already ordered a temp sensor, and i have it, i am just waiting for my new water pump to do the install, but after looking at the P/N, i see that the sensor i bought is #8 in the realOEM schematic. So my question is, should i also get the other sensor? and why are there two? does that mean one sensor tells the computer how hot the engine is, and the other sensor tells the gauge how hot the engine is?
the water pump (which decided to go kablooie a few days back) should be here on Saturday, so i will be doing the install then, and i will update this thread.
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ok put in the new water pump and temp sensor, the #8 in the above post, and no difference. Still a terrible cold idle, with the idle rising as the car warmed up, and the temp gauge is still almost at the 3/4 mark.
bummer. I guess i will try a mustang O2 sensor next.
EDIT: and the other sensor, PN 12621710512 according to realOEM, which actually reads the temp for the temp gauge, is listed on Pelican for just being for the 325 and M3, not the 318. I assume it is the correct part for the M42, because it has that same part number, right?
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I used AC hose to replace the collapsing one. Its so thick you really cant even bend it.
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K Im following this thread since I have the same issue. However I drove it around the with revs up for a couple of minutes. Now my idle is stable but there loss of power throughout the whole rpm range.
So far I replaced with new idle control valve, throttle position sensor, and new intake boot. All hoses are less then yr old.
Maybe between the 2 of use we can throw enough parts at it to find out whats wrong. haha. I'm gonna replace the cat and exhaust next to fix the leak I have...maybe the prob is a loss of back pressure?
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i dunno, but i just ordered an O2 sensor, and i am going to see if that fixes my problem.
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I replaced my 02 recently also.
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Had the same problem, traced it to the flapper in the MAF sticking. Cleaned and lubricated it and the car idles perfect. Hope this helps.
Aloha
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Ok i just replaced my O2 sensor, didn't help the idle issue. My car will stall out at an idle while cold, but runs fine when it is warm.
what can it be?
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Had the same problem, traced it to the flapper in the MAF sticking. Cleaned and lubricated it and the car idles perfect. Hope this helps.
Aloha
i'll try this. But did the problem happen to you only when the car was cold?
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Ok I might try replacing the fuel filter
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op any updates?
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Not sure if you have done this, but do the stomp test to see if you have a leak or bad sensor.
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I just tried the stomp test. I believe the code was 1444. I interpreted the first long blink as the restart of the cycle.
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So that means everything is ok for the most part. Narrowing this can be hard. First thing is to borrow an ECU from a working car. I have heard this can cause the issue you are having and it can be sporadic. Something you can visually inspect it and see some bad solders.
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went out and put some chevron with techron injection cleaner today. Gonna see if that makes a difference.
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I drove around a little today. The injection cleaner seems to have helped a little. I feel the throttle response is almost back to normal. The idle pretty level now. Its weird that the engine still shakes a little. I changed the cat with a "newer" one today. will see if this will change improve things
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no updates on my end. Still runs like crap when cold, actually doesn't idle at all, you have to hold the rpms with the gas pedal.
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Bringing this thread back to life, because I have a similar problem. My car seems to run fine starting cold (like, sitting all night in 10* weather cold), but it starts to run like crap as it gets up to operating temp. It misses and bleeds off power under constant throttle, and idles really low. Once it's at operating temp, it runs fine except for a lumpy idle.
Any updates OP? I've ordered a coolant temp sensor, but it'd be cool to see if you figured out a fix.
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I'll assume you have checked the little wire that is supposed to be unplugged as referenced in the other thread about hot running problems?
Bringing this thread back to life, because I have a similar problem. My car seems to run fine starting cold (like, sitting all night in 10* weather cold), but it starts to run like crap as it gets up to operating temp. It misses and bleeds off power under constant throttle, and idles really low. Once it's at operating temp, it runs fine except for a lumpy idle.
Any updates OP? I've ordered a coolant temp sensor, but it'd be cool to see if you figured out a fix.
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Yup, I tried that. No improvement, unfortunately. The wire was where it was supposed to be for a US Cat car.
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How are your hoses under the intake? Have they been replaced or modified? Maybe there's a hard to find major vacuum leak somewhere under there.
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As far as I can tell, all of the vacuum lines are fine. I did the mess under the intake hose delete a while back, and replaced everything I could. I'm pretty sure it's something related to a sensor somewhere, because the problem really only occurs at certain engine temps. I was thinking about cutting off my cat, since I don't have emissions to worry about where I live, and I have a feeling that the problem has something to do with it for some reason.
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I bought my O2 from a local mainline parts house, it came in another brands box but inside was a nice shiny Bosche O2 with the exact same markings as the used one I took out.
it was about 90 bucks.
Dave
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Its possibly your cat might be stopped up. My car currently has no cat, but I cant stand the smell when I get out of the car (smells like an old chevy or something) Seems like you can get a universal fit catalytic converter for about $70.
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ok dudes I have an update.
I went to a junkyard, found a stripped M42 sitting in the dirt next to a gutted 1991 318i, and the ICV was still dangling there on a severed hose, so I swiped it, paid about $8 for it on the front desk, slapped it in my 318is, and BAM! issue resolved! it now starts flawlessly without a single shudder on brutal sub-zero mornings!
So easy! it just needed another ICV. I have just been too lazy/broke to buy one, but $8 is hard to beat! the junkyard btw is upullandpay.com. check it out.
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hmm i have the exact same issue as you but along with it my gauge won't work. i am thinking i have the same issue, can you post a picture of the icv? i am about to clean it if i find it and i guess maybe my temp sensor is bad so i am gonna try and swap one from another motor because they appear to have the same part #
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told ya
:)
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This is a good thread. I've not worked my way to the motor- yet- in my restoration, but I get this from time to time.
191k on the clock, and perfect starts and everything no matter the temp outside. However, if I use the AC, drive for a while, shut the car down for even a few minutes, it starts right up, but idles like total crap for a few seconds. I am very particular about shutting off the radio and HVAC prior to shutting down the motor.
I have thought I just have an intake leak somewhere, but I also think I might have a sticky (despite being brand friggin' new) AC compressor clutch. My O2 sensor is more or less in spec.
Nothing really to add, but I wanted to mention a couple things for someone searching on this issue.
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I think the M42 uses a stepper motor ICV vs the earlier Motronic units that use a plunger style system. When powered down typically the stepper remains in its last position, whereas the plungers return to the position of least pressure.
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I think the M42 uses a stepper motor ICV vs the earlier Motronic units that use a plunger style system. When powered down typically the stepper remains in its last position, whereas the plungers return to the position of least pressure.
Makes sense. So in other words, nothing I can do?
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I believe my ICV is fried as well. I did work on the E36 a few days ago and when I was done the idle was horrid. I tried cleaning the ICV out again today but to no such luck with the idle.
I took the screw for the throttle plate out and happened to have a screw that was the same only longer so I screwed it in and set the idle to about 950rpm with the A/C on. With A/C on before it was about 450rpm and if I gave it gas it would die if I let the throttle pedal out.
Without A/C the idle is about 1000rpm which is where I have wanted it for awhile anyway. I get alot of flywheel/clutch chatter(especially with A/C) and at that idle speed there is virtually none.
I figured it was the ICV because the engine would rev and run perfectly fine otherwise. If I was driving with A/C on and let off the gas the engine would die (clutch disengaged). It would bog to about 450rpm without the A/C.