97 318ti sometimes stalls after starting, runs rough
 

Sometimes my '97 BMW 318ti starts then stalls. It'll start again but run very rough, sounding starved for fuel. If can keep RPMs high and keep it going for a few minutes, it'll start running OK. I've taken it to two mechanics and they both said the car checks out fine (plugs, cleaned out intake, computer has no error, etc). Of course, the symptom didn't avail itself to the mechanics. This usually happens when the car has been driven, then left for a few hours (not hot / not totally cold). Any ideas?

Thx

check the intake boot for rips, remove it completely and bend it to see if there's a rip in between the ribs, where it won't be very noticeable

Thanks! I checked the intake boot and didn't need to remove it to see it should be replaced. It appears to be the original and the rubber has visible cracks near the clamp and small cracks appear when I squeeze it elsewhere (like an old tire with age cracks). I can't tell that any of them leak air tho. I'll order a new boot today, replace next week and see if it solves the problem.

How did you come up with this solution? Have you experienced this symptom?

Thx

I had the same problem.. wasnt the leak - was the crank position sensor.
Eventually just did not wanna start at all - specially when cold.

Good luck. M

This suggestion should be on a big banner at the top of this website.

I would say it is the single most likely problem for poor performance on these cars.

check the vacuum as well, ask me how I know. But if none of these work, you may want to clean out your idle control valve, ask me how I know again :shifty

i thought the problem for the poor performance was the m44 or m42 motors they put in these cars..? lol

I can't seem to get my motor to idle like I want, so I'm just ripping it out totally lol. . .it shouldn't have been acting up, see what you did you bad M44...LOL! just kidding, I know it needs hella maintenance

yup, that's exactly what was wrong on my car when I bought it and there have been a lot of other members here with the same problem

Update: Car ran great for several weeks while I was waiting for the new intake boot to arrive. The boot arrived Wednesday, but I wasn't in a hurry to install it, kinda waiting to see if the symptom would occur again (was using STP gas treatment because I'm a bit superstitious). Thursday, on the way home, I filled the car with gas and Friday morning the symptom was back..stalling (even if I sit parked holding rpms a 2k, it would run for a little while then stall). Luckily, I live on a hill and the coast to the bottom keeps it moving enough for the symptom to go away. Also even when the car is hot, if I park on a steep incline or decline, the symptom seems much more likely to occur (it did this Friday when it was fully warmed up). As soon as I start moving, it stops and the car runs great. My local BMW guy says (I stopped by Friday) it's the fuel filter which I am changing Monday. Now am thinking it may be the fuel filter or the intake sock at the bottom of the gas tank. When I purchased the car a few months ago, the dealer had run the tank nearly dry..not just into the orange but to the bottom of it. Last night I installed the intake boot...like I said the old one had cracks anyway (none looked completely thru tho). Thanks for your comments / advise.

I had the intake issue last year, that was fun...fixed that. Now I have lean issues. I just had my injectors flow-tested and sonic cleaned and my dead spot was on the back injector. I was limping on 3 and 4 cylinders back and forth and stalling. Pull your plugs and post what color they are per cylinder.

Just got back from a drive and find that if I drive at a very slow speed (at or less than 1000 rpm (car is automatic)) on a certain back road with very steep incline with sharp curve (5 mph situation) car will replicate the problem... It feels as tho it is gas starved...stalls, wait a second, and it starts again and goes a little farther. When the road levels off from steep angles, car is ok again.

which way on the incline are you going...up or down?

up

Not saying this is the problem but just a thought. If you are going uphill your engine needs to work harder/needs more fuel to propel the vehicle forward. If you have a weak spot in your fuel system you could be leaning out. If pump wasn't able to suck up the fuel it would be burning out since fuel flowing through it acts as a coolant. While I don't believe this is your case. So from that point you have your fuel filter, fuel pressure regulator, and fuel injectors. All potential weak spots when leaning out. Again, pull your plugs and check the color of the deposits on them to see if there are any differences in color between the 4. Color can be an indicator as to what is or is not happening in your combustion chamber.

Someone mentioned crank posistion sensor. I've experienced that once. I wasn't able to start my car at times. The sensor wasn't picking up any signals therefore my ingintion system would not fire. It was random for a very short time and then my car just wouldn't start at all. Replaced and Kosher.

Then vacume leak...that's possible too.