Author Topic: idle problem possibly afm please help (Read 4458 times)

nofear3544 · « **on:** October 16, 2007, 10:55:12 AM »

I have a 91 318is it starts up fine every time but when u go to rev it, it will stall unless u keep your foot on the gas. It runs really bad at 30 mph and stalls at every traffic light or stop sign but will start every time. I thought it could either be the oxygen sensor or afm. also the check engine light comes on and off frequently.

kowalski · « **Reply #1 on:** October 16, 2007, 08:32:31 PM »

sounds like a vacuum leak to me.

vitesse · « **Reply #2 on:** October 16, 2007, 09:43:01 PM »

Ya, it does sound a bit like a vacuum leak, although it shouldn't run poorly at 30mph with just a leak (mybe if it was a huge leak, but then it shouldn't idle at all really. Those symptoms could also be the afm, or a bad TPS that is sending the wrong signal. Best thing to do would be to pull the code that comes on frequently and see what it says.

Febi Guibo · « **Reply #3 on:** October 16, 2007, 10:12:27 PM »

see if you can swap in a known working afm, takes a few minutes; while yer at it, clean your throttle

nofear3544 · « **Reply #4 on:** October 17, 2007, 09:50:30 AM »

i swapped in a different afm and it didnt help at all. Could it be my oxygen sensor? I just replaced my hoses and it seemed to not help at all. also what is TPS?

christophbmw · « **Reply #5 on:** October 17, 2007, 10:01:52 AM »

Quote from: nofear3544;35908

i swapped in a different afm and it didnt help at all. Could it be my oxygen sensor? I just replaced my hoses and it seemed to not help at all. also what is TPS?

TPS is the throttle position sensor, what codes are you getting? have you smoke tested the intake sstem for leaks? hows your fuel filter? or air filter?

nofear3544 · « **Reply #6 on:** October 17, 2007, 10:33:31 AM »

air filter is fine idk when the last time the fuel filter was replaced i just had a new fuel pump put in. As far as codes go i dont have a tool to check them. I think im going to order one. I just checked my wires and they look fine. While the car was idling I tried opening the intake door and the car just bogged down and stalled. Ive been searching these forums and i couldnt find anyone who had a problem like this. also would installing a performance chip affect this?

vitesse · « **Reply #7 on:** October 17, 2007, 11:10:59 AM »

I wouldn't think a performance chip would do this, but I've seen stranger. Are you asking because you just put in a performance chip before you started having issues? Try unplugging the throttle position sensor with the car off and start it, see if it is any better. It could also be a vacuum leak, but you say you replaced the hoses, so you mean the whole bird nest of them under the intake??

nofear3544 · « **Reply #8 on:** October 17, 2007, 11:54:52 AM »

I installed the chip about two months ago and had no problems until now and yes i replaced all the hoses.

nofear3544 · « **Reply #9 on:** October 20, 2007, 11:22:20 AM »

okay everyone, i just checked out the code and its coming up 29 which in the book says its the AFM. I tried putting the other afm that I have on my other (running) car on and its no different the code is the same. any clues as to what it could be? possibly a broken wire?

RED IS 91 · « **Reply #10 on:** October 21, 2007, 09:57:07 AM »

don't you have to disconnect the battery to clear the codes

?

nofear3544 · « **Reply #11 on:** October 24, 2007, 01:21:59 PM »

Okay so today i went out to mess with my car trying to find something wrong with my afm and i decided to pull everything out. when i started taking out the box and the boot i noticed that on the boot there are two places for you to connect hoses. I never knew that there were two holes and that one of them need to be plugged. Even my mechanic couldnt find this problem. After plugging it, the check engine light went off and car began to run fine with a little problem idling (i think its from not driving it for a month). so thanks to everyone for their input it would all have been helpful if it weren't for my stupidity.

EN318isPDX · « **Reply #12 on:** October 24, 2007, 01:34:04 PM »

Quote from: nofear3544;36494

Okay so today i went out to mess with my car trying to find something wrong with my afm and i decided to pull everything out. when i started taking out the box and the boot i noticed that on the boot there are two places for you to connect hoses. I never knew that there were two holes and that one of them need to be plugged. Even my mechanic couldnt find this problem. After plugging it, the check engine light went off and car began to run fine with a little problem idling (i think its from not driving it for a month). so thanks to everyone for their input it would all have been helpful if it weren't for my stupidity.

I had to replace that boot so it came with a new plug otherwise i might have missed it.. thank you bav auto for sending me the extra plug hehe, also the hose that connects to the L connector was tapped up on the car when i bought it

vatos_p · « **Reply #13 on:** October 25, 2007, 05:29:00 AM »

I had the exact same problems , and the fault was the injectors...take them for cleaning or change them with new ones , also the fuel pressure regulator...
i did this and everything came back to normal again... ( to get there i had to try new idle valve , new afm , new hoses , new ECU , new oxygen sensor - i tried all this and still with problem , then i changed the injectors and the fuel pressure regulator and suddenly everything fixed... )