Erratic Idle/Stalling on '98ti

[anthony318ti]

Originally Posted by danimal17

Sorry to keep jerking you around, but today the idle was smooth and there was no stalling. The only explanation I could think of is that it was above freezing outside today, but not yesterday.

To answer your question though, when it did stall, it did take a few dead cranks before starting back up.

Lol its ok... Well just as long as she's running fine thats all that matters. if you get a chance try getting the error codes read. Hope your car runs smooth from no on.

[danimal17]

Ok so I've been driving for a few more days now. The idle is still smooth, but I'm still stalling when idling like before. I cleared the codes after replacing the PCV and intake bellow. Checked the yesterday and I'm getting a P0420 and P0100.


A code P0420 may mean that one or more of the following has happened:

•Leaded fuel was used where unleaded was called for
•An oxygen sensor is not reading (functioning) properly
•The engine coolant temperature sensor is not working properly
•Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
•Retarded spark timing
•The oxygen sensors in front and behind the converter are reporting too similar of readings

P0100 is an MAF circuit malfunction

I suppose it's possible that a problem with the MAF could cause me to run rich and consequently a P0420. In the Bentley manual, it shows ways to check MAF sensors on older model cars, but not the M44 engine. Anyone know if there's a an electrical test for it?

[anthony318ti]

Originally Posted by danimal17

Ok so I've been driving for a few more days now. The idle is still smooth, but I'm still stalling when idling like before. I cleared the codes after replacing the PCV and intake bellow. Checked the yesterday and I'm getting a P0420 and P0100.


A code P0420 may mean that one or more of the following has happened:

•Leaded fuel was used where unleaded was called for
•An oxygen sensor is not reading (functioning) properly
•The engine coolant temperature sensor is not working properly
•Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
•Retarded spark timing
•The oxygen sensors in front and behind the converter are reporting too similar of readings

P0100 is an MAF circuit malfunction

I suppose it's possible that a problem with the MAF could cause me to run rich and consequently a P0420. In the Bentley manual, it shows ways to check MAF sensors on older model cars, but not the M44 engine. Anyone know if there's a an electrical test for it?

if you have a mate with an E36 M44 might want to swap the MAF other than that i do not know how to test them. best of luck.

[Blue]

Sounds like I'm having the same problem you did a few months back. Help! I've already had my CAM sensor and idle control converter replaced and the problem is back How is your car? What ended up being the problem for you? Any help would be greatly appreciated!

[danimal17]

Blue,

Sorry for never following up with my resolution. I was having 2 problems: erratic idle and stalling at stops with engine warm. I replaced my PCV valve and that solved the idle problem. Apparently you're supposed to change them ever so often ($50 more or less if I remember correctly). Then I replaced the mass air flow sensor like anthony said and that fixed the stalling (Bought one off a friend for $70).

There are just so many things that can cause idle problems with an E36, it's hard to pin down sometimes. What exactly are your symptoms?

[Blue]

My car stalls when I'm stopped in traffic and at lights if I sit there for too long. I find it's worse if I've already been driving her for awhile. It didn't stall once today because I was never stopped for more then 30 seconds at a light and the majority of my drive was on the highway--horray for small miracles! I've resorted to driving with two feet and it's completely unsettling because every so often the rpm's spike while I'm stopped and trying to keep the car from stalling by keeping the rpm's around 700 (so I hit the brakes and then the gas to prevent stalling) My mechanic was convinced that fixing the CAM sensor and idle control valve would fix it. He was shocked when I called him this morning and he seemed irritated about the whole situation. He says he'll give me a discount on the CAM sensor and put back my old idle control value back in and then start all over with rediagnosing it. I told him I just want my car to work and happy to pay for necessary repairs that fix the stalling. That being said, I've already sunk $700 into this and it's still stalling. He seems stumped over it and I'm stressed because I NEED my car to get to work!!!

What's an E36 and what does PCV stand for?

Thanks for the speedy reply

[danimal17]

PCV valve= positive crankcase ventilation valve.
E36= basically any 3-series from 1992-1999.

Honestly, it sounds like you may have a bad mass air flow sensor. What you described is exactly what was happening to me. They are NOT cheap however, so if possible borrow one from a friend and see if that fixes your problem. If not, some places sell them cheaper than others, but keep in mind not to buy a generic MAF.

What car do you have exactly and how many miles?

[Blue]

'98 318ti with 250,000 km. I'm bringing her in on Thursday morning. The mechanic fixed the CAM sensor and idle control value so they will likely swap out the old parts since that didn't fix the stall problem. Then the mechanic said he would start to re-diagnose it and that sounds very expensive--they charge per hour. I wanted to come in with suggestions from this site. I was hoping it would be a vacuum leak somewhere...I think that would be cheaper. I'm pretty sure they would use a MAF from BMW because they specialize in BMW's. Not sure thou... How much do you think replacing the MAF would be (parts + installing) roughly?

[danimal17]

The MAF is expensive as you can see here:

http://www.pelicanparts.com/cgi-bin/...IRFLOW%20SENSO

Luckily, it's a quick 10 minute job. I hope it is a vacuum leak so you save some money!

Good luck

[Blue]

Thanks for the info! I still have not heard from the shop He said he would replace my old idle control value converter and refund my $ for parts and labor. He said it takes .4 hrs to fix the idle control value and 1.1 hrs for the CAM sensor. Does that sound right to you? I thought it was the other way around. I'd like to think he wouldn't try to pull a fast one I really appreciate all your input. It has made this whole process a little less stressful for me I can't WAIT to get my car back--miss the good old days of having a reliable car to drive.

[danimal17]

1.1 hrs for the Cam sensor sounds right because he has to take the intake manifold off to access the connector. As for the idle control valve, it's a very quick job. Just two bolts and a quick gasket swap. .4 hrs isn't far off either.

[Blue]

It was the MAF!!!! I've been driving her for about a week with no stalling It's such a relief to have this fixed. It cost way too much and the mechanic still charged me an hour for diagnosis (even though when I came in I asked him to check the MAF first). I guess since it was my second time back to fix the same problem, he wanted to be sure this would do it. It cost WAAYYY too much. I knew the ballpark should have brought it to about $150 less then what he charged but, I was at my wits end with both the shop and having a car that kept stalling on me. I learned a very important lesson from this experience and that is thanks to people like you and websites like this--I'm not completely at the mercy of mechanics. If I had come to this site prior to taking my car in, I would have saved myself a lot of time, $$ and heartache. I wanted to express my heartfelt appreciation for helping me out with this danimal17. You really know your stuff and it helped me out a great deal. Thank you, thank you, thank you!

[danimal17]

Glad that all worked out for you!