M20 Stalling When Warm/ Operating Temperature

[jniuk]

Hey, trying to revive this - same symptoms, fine on cold, as your drive (mine takes a span of 30 minutes) before it completely shits the bad at a stop sign. Was your issue the ICV? I also swapped my ECU, and has a bad ish idle, but how long did yours take to get used to your engine?

[bmwfan52]

I think your referring to the CPS sensor, the O2 sensor wiring is on the opposite side of the engine/ not located by the belt pulleys. I've seen your issue a few times in the past though, it happens when people break the clips which hold the CPS sensor/ Pulse sensor wire to the timing cover. Without those clips, the CPS/ Pulse wires aren't tightly against the timing cover and will eventually start touching the belt pulley/ rub into to wire(s).

Thanks for pointing that out. ill try to edit it so nobody gets confused and starts looking for the o2 sensor in the front of the engine bay.

[KIRIEIW]

I just overcame the cutting out/ loss of power while accelerating, I had rebuilt my m20 droped it in ended up changing my o2 sensor for a better one, car was running fine then I started losing power all of a sudden checked everything that had any thing to do with the fuel system twice and just when I was about to tear my t-shirt hulk hogan style I decided to double check my o2 sensor I had quickly installed a week ago when I was trying to resolve my no fuel issue. turns out the o2 sensor wire had been eaten away rubbing on the belt. changed the o2 sensor and I have been driving the car since no issue.

my bad I think i got the wrong thread guys should i delete my entry?

I think your referring to the CPS sensor, the O2 sensor wiring is on the opposite side of the engine/ not located by the belt pulleys. I've seen your issue a few times in the past though, it happens when people break the clips which hold the CPS sensor/ Pulse sensor wire to the timing cover. Without those clips, the CPS/ Pulse wires aren't tightly against the timing cover and will eventually start touching the belt pulley/ rub into to wire(s).

[bmwfan52]

I just overcame the cutting out/ loss of power while accelerating, I had rebuilt my m20 droped it in ended up changing my o2 sensor for a better one, car was running fine then I started losing power all of a sudden checked everything that had any thing to do with the fuel system twice and just when I was about to tear my t-shirt hulk hogan style I decided to double check my o2 sensor I had quickly installed a week ago when I was trying to resolve my no fuel issue. turns out the o2 sensor wire had been eaten away rubbing on the belt. changed the o2 sensor and I have been driving the car since no issue.

my bad I think i got the wrong thread guys should i delete my entry?

[KIRIEIW]

Just to update this, the rough idle has settled and the car's now running fairly smooth. I'm assuming the ECU re adjusted to the replacement idle control valve. Also, the car hasn't stalled yet, I've put on over 800 miles now and it's been my daily driver since swapping out the ICV. The low idle reading is due to bad SI batterys.

[mazzo]

Can you also check your distributor cap and rotor?

[KIRIEIW]

Well my tach was reading 250RPM's today at idle, now we all know that's not possible especially when the idle sounds the same as it did a few days ago. The SI board is failing is my guess, but that's the least of my worries. I've been driving the car everyday since replacing the ICV and it still hasn't stalled on my once which is awesome. It idles somewhat better, but it's still has that "unhappy idle" sound once the car gets to operating temp. Since I can't really rely on the tech for an accurate idle RPM reading, I'll just take a guess that it's probably idling around 600. Clocking the AC button doesn't really bump up the idle much, but the extra maybe 50RPM's it gives the car (yes I know it should bump up the idle up around 300RPM with the AC switch on) does help.

[KIRIEIW]

Ok well the car still hasn't stalled, but it's still idling low. In fact, it's gotten even lower over the past couple days. Once warm, it idles at around 475-500RPM's. Clicking the AC button doesn't help much, maybe brings it up to exactly 500RPM if even that. I still can't get over the fact how well this thing idles and sounds when its warming up. Sounds just like a normal M20 should and I've owned 4x m20 cars, currently owning two. As soon as it's up to operating temp it still idles, but you can hear it's not running happy (of course plus you can see it's idling on the low side via the tach.)

Either the stalling problem has been fixed but the low idle issue remains, or the stalling issue has just went away temporally. Either way I'm even more stumped then before, I'll most likely try another idle control valve just because since swapping it out the stalling issue went away, but doubt it will help. I'm wondering if my rear main seal leak can cause a big enough vacuum leak to cause low idle issues. It did pass smog last Saturday with good numbers though..

I'm just about forced to drive this car around now as my temporary daily, my other car just started whining and clunking from the rear end TODAY. At least work is only a few miles away.

[KIRIEIW]

M20 Stalling When Warm/ Operating Temperature

Is your e30 capable to do stomp test? Is yes, what is the code?

You can only a stop test if the check engine light is currently on, or was on long enough to store a code which wasn't the case for me. The check engine light would only flash for a split second.


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[mazzo]

Is your e30 capable to do stomp test? Is yes, what is the code?

[KIRIEIW]

Drove it to work today and still no stalling


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[Som]

The WOT connections on my TPS had cracked at the solder points. It tested faulty/good intermittently. I just resoldered with a little added solder and the problem was fixed. Never really looked at the idle switch side, though, to see if the same problem could exist there, but I don't see why not.

I've read that you should be able to clean ICVs, but it's not something I've looked at, which is why I figured trying a different one would help. If it ends up working, I'd wonder if it had something to do with the connector/wiring in that area. Maybe it wasn't plugged in right the first time around? I haven't really been able to find a good description of what actually fails when they "go bad". According to this wiki (http://www.e30zone.net/e30zonewiki/index.php/Intake), it's "rare that they fail completely".

Problem fixed is a problem fixed, though. :) Glad it's working out!

Som

[KIRIEIW]

You can usually just clean an ICV and it will work again. I found that the TPS (throttle position switch) can test good and still not work--the solder joints get old and lose conductivity and even though they look ok, they are not. I have fixed them by just adding new solder.

Well I cleaned the original ICV and the problem remained, since installing this used ICV though it hasn't acted up. Like I said though, I still have my fingers crossed this fixed the problem. I've only driven it 10 miles since, but before I couldn't even drive it a half mile with out getting stranded.

Hmm interesting on the TPS, I'd think if the solder joints broke it would test faulty.


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[goldenbb]

You can usually just clean an ICV and it will work again. I found that the TPS (throttle position switch) can test good and still not work--the solder joints get old and lose conductivity and even though they look ok, they are not. I have fixed them by just adding new solder.

[KIRIEIW]

Good news! I swapped out the ICV today and it hasn't stalled yet. I was messing around in the morning today and the car would run with the old one un plugged at operating temp, but as soon as you re connected the plug it would die right away. After that test, I figured it would be worth swapping it out for another one and the car's been running fine *Cross fingers* since.

The other good news was I got it smog'd right after and it passed with great numbers! I should have just swapped the ICV from the very beginning, I just found it un likely to be the issue because the old one in the car would buzz as soon as the ignition was turned ON. To future readers, don't assume your ICV work's because it's buzzing with the key ON, your best bet is to swap it for another used one or at very least check if the flap is binding (which mine wasn't, but wasn't very smooth to turn).

Will update the thread if this permanently fixed the problem or not. Thanks everyone for the suggestions and help.