Author Topic: Never-ending idle/rough start problems :( (Read 4692 times)

arcter · « **on:** March 01, 2010, 12:02:56 AM »

Hey guys, here's an update. I had it in to a shop that I used to bring my E34 to and they said they found a few leaking hoses connected to the ICV as well as one of the cylinders not getting enough spark when cold. So they replaced the hoses and the ignition wires/coils etc. and gave me the car back. For a couple days it seemed totally fixed other than when I'd start it up totally cold it would dip down below idle a little bit until I gave it some gas. But the extremely rough start problem was gone as well as the dipping idle when the car was warmed up.

But the car sat since yesterday and tonight I started it up for a quick ride and my rough start problem was back. That and yesterday when I drove it I noticed some of the same low-dipping idle when driving even when warm. Any ideas? I'll give it back to the shop to see if they'll fix it without charging me more since they assured me they found the problem, but the problem is really starting to bother me.

Murdul · « **Reply #1 on:** March 01, 2010, 03:26:27 PM »

I would go over the hoses they replaced and make sure the connections are tight. Then if you don't find anything take it back in.

RED IS 91 · « **Reply #2 on:** March 01, 2010, 04:18:27 PM »

Did they check the icv ,Maybe it needs to be cleaned . Coolant temp sensor also.

arcter · « **Reply #3 on:** March 01, 2010, 07:46:52 PM »

Quote from: RED IS 91;88643

Did they check the icv ,Maybe it needs to be cleaned . Coolant temp sensor also.

Well I dropped it back with them this morning and from the start they seemed to be preparing an excuse before I left, saying it could be the lifters or carbon buildup and the only way to fix that would be to do a valve job. Sound like BS? Of course they didn't warn me of that before they acted sure it was the ignition problem. I obviously wouldn't do a valve job just to fix a rough start/weird idle. They'll keep it tonight and hopefully find something tomorrow.

flyinglizard · « **Reply #4 on:** March 01, 2010, 09:25:40 PM »

A weak lifter will make noise and not lift the valve at the same time. The carbon will be there, hot or cold, and the idle will not change due to carbon, A compression check should show carbon if over 210psi. But these engines seldom get carbon, due to good oil and lack of torque. Drivers rev the crap out of them to drive them.
I have ICV or small intake leak elsewhere. maybe injector.
Compression test, leak down test, injector test. ignition test, plug change.

arcter · « **Reply #5 on:** March 01, 2010, 11:35:20 PM »

Quote from: flyinglizard;88678

A weak lifter will make noise and not lift the valve at the same time. The carbon will be there, hot or cold, and the idle will not change due to carbon, A compression check should show carbon if over 210psi. But these engines seldom get carbon, due to good oil and lack of torque. Drivers rev the crap out of them to drive them.
I have ICV or small intake leak elsewhere. maybe injector.
Compression test, leak down test, injector test. ignition test, plug change.

Hey thanks for your reply again. Well I did have a compression test a couple weeks ago when this first showed up and showed 175 across all four cylinders. So in your opinion the lifter/carbon ideas are probably bunk? I'll see if I can convince them to look more closely for a leak.

By the way, what about the oil being too heavy? Just thought I'd ask but I'm sure it's ok, there's 20W50 in there now. I live in California but it's been rather cold at night.

DesktopDave · « **Reply #6 on:** March 02, 2010, 06:59:33 AM »

I'd double-check the ICV. Might be dirty, oily or just flaking out...they're a pretty common problem.

Seems like you're close to solving the problem...the shop did a good job with the coils/wires & hoses. I'm sure the valve/carbon theory is their way of saying they're not sure what it is but they're willing to spend your money to check it out thoroughly.

arcter · « **Reply #7 on:** March 02, 2010, 10:00:22 AM »

Quote from: DesktopDave;88694

I'm sure the valve/carbon theory is their way of saying they're not sure what it is but they're willing to spend your money to check it out thoroughly.

Well, they had the car for a week and didn't warn me that the ignition stuff might not fix it. They acted sure. So I can't really go along with their alternative theories before they work with me a little bit on justifying that money spent.

By the way, they say they cleaned out the ICV. I'll see what they say today.

Choking Hazard · « **Reply #8 on:** March 02, 2010, 11:03:55 AM »

My guess is spark plug wires...

arcter · « **Reply #9 on:** March 02, 2010, 10:41:34 PM »

Quote from: Choking Hazard;88700

My guess is spark plug wires...

Is that the same thing as the ignition wires they replaced (talked about that above, they seemed confident it would fix my problem)? Cyl. #4 wasn't getting proper spark but the cold start problem only seems to have been slightly improved, not fixed.

I got the car back today. They couldn't find any problems and went back to carbon buildup being their first suspect. They gave me some stuff to put in the gas tank and I'll try it out over a couple of full tanks. Don't know what to think of this.

Also, quite a hefty amount of blue smoke came out of the car after I first got it back, even just sitting at a light and especially when leaving a stop. Luckily it seemed to stop after warming the car up for a while and they said that the way they tested the car, starting it up cold a lot, may have allowed for some buildup if I've got some slightly worn valve guide seals. Hopefully that's all.

iamcreepingdeath · « **Reply #10 on:** March 03, 2010, 09:45:27 PM »

its gotta be your ICV. sometimes cleaning it doesn't help. I had a similar problem for a long time, it would barely run when cold, super rough, and I had to be on the gas to keep it running when cold, but ran fine when warm. Then I picked up a ICV at a junkyard for about $8, slapped it in, and BAM! it runs perfectly to this day, cold or hot. definitely worth the $8.

Sarstan · « **Reply #11 on:** March 11, 2010, 03:10:02 PM »

Just a quick drop on this. My car has had a rough idle when it first comes off a rev and it doesn't like to idle too well from a cold start. One weekend I decided to have a look around and found the boot on my air intake (the rubber after the plastic sensor and the metal connecting to the engine) was really cracked and clearly must be leaking. I have since taped it up with duct tape and it leveled out my idling until recently when the tape's starting to lose it's stick.
Just though I'd throw those two cents in and also mention I plan on getting a new one when I get around to finding one online.

DesktopDave · « **Reply #12 on:** March 11, 2010, 03:46:51 PM »

Sweet! These cars are famous for vac leaks. Keep the ICV in mind if the idle problems come back. I'd also suspect that poor readings off the crank or cam sensors can cause misfires & make the idle pretty rough.

Intake: BavAuto for $37; Pelican for $38; BMA for $39

BlueBMW · « **Reply #13 on:** March 11, 2010, 10:36:36 PM »

Where are you located? I'll come fix the darn thing! Sounds like the shop is running low on options.