Idle Problem on my 98 318ti. Please help!

[mt3ch]

The 318ti in my household is a 1998 Auto w/ 69K miles.

Ok...the scenario is at idle the car drops revvvvvs almost to the point of stalling, but the revs kick back up right before it does. Also when car is in neutral the revs stay up and then drop. When the AC is on the revs go up and usually everything is fine, but there is an ocassional drop when idling yet again. Car is fine when accelerating and decelerating and there is no hesitiation. Problem is just @ IDLE.

If anyone is familiar with this scenario, please post.

Thanks in advance!

Justin

[1996 328ti]

And the CEL is not on?

If the CE light was on I'd say it could be the MAF or Idle Control Valve.

BTW- Please use your personal photo gallery for pictures. Then you can link to your photo.

[chadder007]

Hmm....I have a 95' model Manual that does the same thing. It just does it at random too.

[BlackM42]

I would also probably suggest the idle control valve. My e30 once was doing what you're describing, so I blasted the ICV with a ton of carb cleaner- fixed it right up.
Maybe vacuum leaks, too...check the rubber intake boot connecting the TB to AFM. (MAF? sorry, I'm OBDI)
Good luck!


Fraser

[ElementalFiend]

Mine is an automatic and also does this.. has done it since I've had it. I just always assumed it was normal.. i'm guessing its not?

[schussey]

mine does this as well, I have plans to slam the ICV with carb cleaner

[J!m]

Here's a thought for you guys to chew on...

I have my secondary air pump disconnected, as it does not fit under the hood at the moment (which causes the CEL, but that's another story...), and the idle at cold start is very nice, but when I add throttle, it will nearly stall, like the intake is choked of...

So, perhaps the cheezy plastic secondary air hose has a hole or crack in it. If the pump is there and working, it will not trip the light. However if the air is not getting in there when the ECU is thinking it is getting in there, this may cause poor idle and 'hunting'.

[ElementalFiend]

hmm, i'll go give my hoses the once or twice over. Thanks for the thought!

[Turbo-ti]

Like BlackM42 says try cleaning the idle valve. When you take it off kinda shake it back and forth if you feel the valve moving back and forth in the valve itself its working. If it doesnt its probably stuck. Also cheak for vacuum leaks around the intake and throttle body..

[tastade]

My 95 manual stalled on me yesterday afternoon. It was doing that same thing, it would idle at 800 or so like usual and dip down. Then it did it a couple times and just stalled. It stalled three times in a row. The rest of the day it was fine.

Outside temp was probably about 85 and I had just driven about 10 miles, parked, went into a store for about 10 minutes, came back out, restarted it, and then it started acting up. After about 5 minutes it was runnin fine again. It almost felt like vapor lock or something.

I am thinking it might have been the cheap gas I used. I never use ethanol, but the only mid grade fuel (89 octane) that they have here in Iowa is ethanol, and I didn't feel like paying the extra for the premium that day (the book recommends 89, but I am forced to buy the 91 since it is not ethanol). Not to mention I was buying generic gas instead of my usual BP. Anyone else had problems running ethanol in the summer? Or know what else this might be? I will look into that valve and make sure it is working freely.

Originally Posted by mt3ch

The 318ti in my household is a 1998 Auto w/ 69K miles.

Ok...the scenario is at idle the car drops revvvvvs almost to the point of stalling, but the revs kick back up right before it does. Also when car is in neutral the revs stay up and then drop. When the AC is on the revs go up and usually everything is fine, but there is an ocassional drop when idling yet again. Car is fine when accelerating and decelerating and there is no hesitiation. Problem is just @ IDLE.

If anyone is familiar with this scenario, please post.

Thanks in advance!

Justin

[318tibimmer]

1st - I always put good gas in my ti (91 oct), 2nd I had a problem like the ones that your having, I hooked up the computer and saw that the O2 sensors were not cross counting like they were suposed to (no mater what they would just read a constant voltage, no change). I went and got the 2 O2 sensors form BMW and put them in, now my ti does much better. every once in blue moon it will do the little dip in RPM thing but the O2's fixed it.

[riker]

yeah mine started doing that after i tried shifting from 3rd gear to 4th gear at full rpms and mis-shifted to 2nd instead (not sure if it actually went in gear, but it grinded like hell) Was about a block from my house, right when I parked, the car stalled. Left it over night, in the mornign same deal, started it up .. really really rough idle and the car just stalled. Checked the oil, it was way below the line, so filled that up, ran the car now it didn't stall but idled really rough. Left the car for about a week, my dad took it to bmw to see what could be the problem, and on the way there it just started acting normal, and drives fine today. It still does the dipping idle at random times, my driveway is kind of inclined, I notice it sometimes when I start up on the incline when the car is already warm. Cold starts are usually ok. I'm not sure what it is, but I need to get the car tuned up ... haven't done a thing since I got it except for oil changes.

[James]

I had the same problem until I've changed the air intake boot. It was cracked in few places which I guess was letting a lot more air enter then it should have. Since that repair, no more idle problem.

[ddiorio1313]

CAM SENSOR! I just had the same problem after getting and inspection 2 done. It ran fine for maybe 15 miles then...kurplunk. It Died. I managed to get it to the mechanic thinking it was something he did. We hooked it up and sure enough it was something else. The Cam Sensor had craped out. It was 114 for parts and shipping. and 147 for labor. I guess part of the sensor is located under the manifold, so he had to take that off to replace it. Sucks, but so far it has been running okay. Oh Yah my check engine light didn't come on until about 6 or 10 stalls later....

[eurekaiv]

Hi everyone, first post and soo glad I found you all! My '98 Manual does the EXACT same thing the origianl poster described and my first TI, a 96' manual did as well. That car had the Idle Control valve replaced under warranty and if I remember correctly they said there was a service bulletin for a "rough idle" on the 96 model year. Unfortunately I had no luck getting the dealer to duplicate and repair the same problem on my '98 while it was still under the CPO warranty. I havn't ever worried about getting it fixed since I've got so used to it I can tell when it's about to stall and blip the gas to get it going again.