UPDATE: Car Won't Idle/New Notes Check It

[shay91]

Hey guys, just like the title said my car will start and you can rev it but if you stop holding the pedal, it'll die. Also, it's lag in the throttle cable so it feels. Because it won't respond and come back up as fast. So I'm assuming that's a lag there. I think I'm going to have to replace my throttle cable but I'm not sure. But I don't know what's making it NOT idle. It'll rumble the RPMS down to about 3-400 and die. You guys are the best at what you know and I always come here for the best advice from people who've experienced the same. Any whom here's my car info..

89' 325i Convertible m20
new fuel pump installed.

hoping to have both problems answered so I can bring my baby home.

*EDIT*

I double checked for leaks past the AFM and didn't get much of a difference however after a few tries the car did idle but it was low and lopey for about 3-5 seconds then it died again. I sprayed carb cleaner around the areas to try and help pin point but still got nothing. It didn't spike the RPMs or anything...

**NEW INFO**

So far solved? Changed out the tps and it actually cranked and idled. It wouldn't at first, just crank and die as usual. But after some fiddling with the injector connectors and some starter fluid it finally stayed on. It's possible that the TPS was bad but it's also possible that one of the injectors weren't completely down. I didn't adjust the old one to see if it was the problem or not, I just replaced it. Twisting the TPS back and forth didn't change the idle afterward. It was a little high but I didn't let it warm up to see if it'd go down. It idled a little below 2000 rpms. It ran with a slight miss that DID smooth itself out. It had a little smoke showing up around the exhaust so I'll be checking the torque on those as well as checking the head torque for 65ft lbs. That whole additional 90* was a little blah to me so I've read that most here have it set at 65ft of torque with seems approximate. Still hoping that when I crank it today it cranks and idles on it's on and I can go ahead and set everything in stone and work on other things. =) I'm happy. I keep updating so that I can hopefully help someone else.

Replaced Parts:
AFM Intake PN: 13 71 1 708 800 - $19.95 BavAuto
AFM Bosch Reman - $72.xx Advance Auto
TPS - $41.28 RockAuto

NOTES FOR TODAY:
-Check idle after initial warm-up
-Check torque for intake and exhaust manifold bolts
-Check/set head torque 65ft lbs
-Recheck idle
-Tighten TPS
-Drive it!!

*********************

If you guys see anything in my notes that I probably shouldn't do, be sure to let me know. Seriously, I didn't go through all this to mess anything up. But I think I'm safe.

[Bene]

mine did that the other day at a stop light. I reved the motor high enough to get in gear and go (was also on a hill). Not even a block away, I put the clutch in to see if it would die and the problem seemed to go away.

You can also adjust the throttoe cable. 22 years is plenty of time for a cable to stretch out.

[hotballs]

Well the throttle doesn't need to be open for the car to idle. Clean out your ICV to make sure that's not the problem.

Other than that it could be a wide array of sensors, AFM etc.

[shay91]

the icv looks great on the inside, it's not dirty.

[ak-]

Intake leaks?

Also, go to your butterfly/throttle in the engine bay and sliiiiiiightly pull it. Do you here a "click" when pulled? If not, your TPS isn't adjusted correctly. Or your TPS could be just not working correctly in general.

[shay91]

no intake leaks. to put into better perspective, everything was working fine when the timing belt broke 3 years ago. since then its been slowly put back together and was completed last year. it was running and idling fine except for when the fuel pump went out and since it's been replaced it wont idle at all.

[shay91]

bump

[defaultName]

It is probably the ICV. My car had the same problem (car would start, would not idle, engine would die) and it was the ICV.

If you know someone with the same car see if you can swap over the ICV to see if that fixes the problem.

[shay91]

not here, it's not too many of them around. But I'm going to buy a known working one off here. I guess we'll find out soon enough.

[jlevie]

Intake leaks, a bad ICV, bad AFM, or a fuel system issue are equally likely at this point. There is a suite of fuel system tests in the Bentley that will assess the health of the fuel system. A smoke test of the intake will tell if/where there are any leaks. If the vane in the ICV moves freely and you can feel it vibrating when the ignition is switched on, it is good. The AFM would be near the bottom of the list and is best diagnosed by swapping in a known good unit.

Other causes are possible, but these need to be ruled out first.

[imprttuner88]

How does one who works out of their house able to perform a smoke test? Not being smart, serious question. I would like to do one to mine just to check it.

[shay91]

people have even went so far as to suggesting the tps. Which with what bentley read, it's possible. My icv hums when the ignition is on like its suppose to be I'm still stuck on this problem.

[shay91]

any more suggestions? I think I will recheck intake leaks.

[bmwm42]

Once the engine is warm will it idle try to get the engine to operatingtemp and see if it holds the idle then

[Bolen1621]

A bad voltage regulator? When mine went bad, you could start the car and only keep it running if your foot was on the gas (when not in gear). The alternator wasn't charging the battery, so after a while the battery wasn't strong enough to keep the car running at idle rpms. It's REALLY easy to check the voltage regulator too, or at least on my Bosch alternator it was.

Good luck figuring it out!