Cold start/idle issues '82 e21

[fcw737]

Hey all. First post since buying my '82 e21 m10 5-speed coupe. Bought from original owner. 250,000 + miles. Great shape. Original black interior. New silver paint. On initial cold start, engine attempts to idle at 400rpm, shakes briefly as it attempts to run, then dies. Same thing on second attempt. On third try, idles around 400rpm then suddenly jumps to 1000rpm and, after warm up, runs like a scalded dog down the road. Very smooth and responsive. Suspect idle control valve or cold start valve but not sure. Fuel system parts I've replaced: fuel distributor, external fuel pump, fuel accumulator, fuel filter, fuel line from filter to in-tank pump. I've done a smoke check and found no vacuum leaks. New plugs and wires. Set ignition timing and adjusted fuel-air mixture to .45 volts. Replacing dead in-tank fuel pump today. Also replacing O2 sensor. Any thoughts? Thank you in advance.

[2002jm]

might want to check the icv. Might be very dirty.
sounds like a very nice car.
jm

[epmedia]

Try some injector cleaner in the fuel tank(s). Then replace the fuel filter again, soon.

[luis320i]

I used to have similar problem , however , my car runs fine between 800 to 1000 RPM , may need some adjustment at the idle screw . It is on the passenger side about the middle of the engine and below the air intake , you may need to move some small hoses to reach that screw , if it is very dirty use wd 40 and be carefull because you may damage the head of the screw if its to tight , also need to use a long screw driver (flat)
Hope it helps

[fcw737]

Thanks, guys. I replaced the in-tank pump and the engine no longer dies at idle. No more noise from the external pump as it's getting help from the other guy now. I will remove and clean the ICV next. That may be the culprit the more I read about the m10. I hope it's nasty and gunned up when I pull it out. Luis320i, I did adjust the idle when I adjusted the fuel/air mix. Thanks for that. One thing I forgot to mention is that, once the car starts and finally idles on the third attempt, it takes a few more minutes for it to drive smoothly. If I try to drive it immediately, it will run very rough and will barely go down the road. But once it reaches a certain point (maybe temperature), it snaps out of it and runs perfectly. Hopefully cleaning the slide valve will fix this. Thoughts? Thanks for everything 2002jm, epmedia and luis320i.

[ibarr]

Thanks, guys. I replaced the in-tank pump and the engine no longer dies at idle. No more noise from the external pump as it's getting help from the other guy now. I will remove and clean the ICV next. That may be the culprit the more I read about the m10. I hope it's nasty and gunned up when I pull it out. Luis320i, I did adjust the idle when I adjusted the fuel/air mix. Thanks for that. One thing I forgot to mention is that, once the car starts and finally idles on the third attempt, it takes a few more minutes for it to drive smoothly. If I try to drive it immediately, it will run very rough and will barely go down the road. But once it reaches a certain point (maybe temperature), it snaps out of it and runs perfectly. Hopefully cleaning the slide valve will fix this. Thoughts? Thanks for everything 2002jm, epmedia and luis320i.

i have the same problem with mine, it idles really low and shuttters a bit before it completely dies. have ordered fuel filter, external fuel pump and fuel pump relay since i bought the car off a guy that didnt drive it much. I am having a problem locating the ICV, any picture of where its hiding? -thanks

[GDAus]

i have the same problem with mine, it idles really low and shuttters a bit before it completely dies. have ordered fuel filter, external fuel pump and fuel pump relay since i bought the car off a guy that didnt drive it much. I am having a problem locating the ICV, any picture of where its hiding? -thanks

Hi .... I'm assuming ICV=idle control valve ..... on a K-Jetronic system its usually called an AAV=Auxilary Air Valve.

Here's a write up on testing etc.

https://www.bimmerforums.com/forum/s...9#post14617069

Note that the resistance for the heater in the BMW M10 AAV is about 48~50 ohms.

[mxl556]

Have you tried disconnecting the 02 sensor and see if it runs better cold?

I'd check the temperature sensor (17C sensor) on the front engine bracket-it is in front of the frequency valve. Mine is broken and I have to run the car with 02 disconnected until I get the sensor (has to come from Germany) as it does not run right until warmed up. It runs fine with 02 disconnected.

Max

[John Adkins]

E21's have a mind of their own when it comes to idle. Try one fix at a time and you'll get it worked out. Leave the mixture adjustment alone for now...things can be made worse. Hard for these engines to idle smoothly below 900 RPM.

[ibarr]

thank you! im pretty new to all this so appreciate the feedback gotcha, have also heard about adjusting/ cleaning out the aux air valve to help