[aesfah]

I've recently begun experiencing rough idle upon startup. About 5 seconds after firing up from dead cold, the RPM drops below 500, then goes up to 800, then car dies. I'll turn it on again, and it dies 5 seconds later. When I finally get it to run, it performs flawlessly - smooth revving and no rough idles. Any ideas on what could be wrong? I'm stumped and CPO ran out last year.

Car has 85k miles. Here's what I've have and what I've already done:

-cleaned MAF w/MAF cleaner.
-added Techron concentrated fuel cleaner with last fill-up
-changed gas stations - use only shell
-battery is 2 years old
-original starter, t-stat, water pump
-installed new plugs last year (10k miles ago)
-replaced 3 of 6 coils under warranty 2 years ago

Recently threw P0172 code (Mixture too rich). Did search, but not sure where else to go from here...

[bumere90]

scan it

[raleedy]

If you a had bad or failing cam shaft position sensor you might have symptoms like this. But you should also (at least eventually) have a corresponding code and/or check engine light (but I didn't have these with cps failure on my E39 530i's M5430B)

[aesfah]

Originally Posted by bumere90

scan it

scanned it and only code is p0172 (rich fuel).

[mxchris727]

You may need to reset your fuel trip adaptation value as this is only happening on a cold start (closed loop fuel trim).

[aesfah]

Originally Posted by mxchris727

You may need to reset your fuel trip adaptation value as this is only happening on a cold start (closed loop fuel trim).

any idea how to do this?

[runwild]

fuel rich means ur not getting enough oxygen and too much fuel so ur drowning out the engine thats why its not starting up right somethings wrong there im not a mechanic so not exactly sure but i would go see one asap and i would check the air filter maybe its so dirty ur cars not breathing...

[aesfah]

just took it to my indy shop - he recommended intake cleaning with a specialized machine. $150. any thoughts on this?

[BMW_Belgier]

Originally Posted by aesfah

just took it to my indy shop - he recommended intake cleaning with a specialized machine. $150. any thoughts on this?

Oh i hate it when they "need" to use "specialized machines"...

[954Stealth]

I had a similar problem a while back. For me it was a loose vanos sensor.

[E9TOU]

Had the same problem a couple days ago. I'm still on warranty so I brought it in, ended up being bad injectors and spark plugs and I believe they had to re-program software for the injectors. I was mis-firing on 2 cylinders.

At first the problem was just on cold start-ups and then it got the point where the car would vibrate violently, then die if at idle. Major white smoke coming out of the exhaust and strong smell of gas - it was basically seeping through the exhaust. Just got the car back yesterday and it runs like a champ (so far).

Here's a vid I recorded of it. Maybe your problem is similar.

[aesfah]

Originally Posted by E9TOU

Had the same problem a couple days ago. I'm still on warranty so I brought it in, ended up being bad injectors and spark plugs and I believe they had to re-program software for the injectors. I was mis-firing on 2 cylinders.

At first the problem was just on cold start-ups and then it got the point where the car would vibrate violently, then die if at idle. Major white smoke coming out of the exhaust and strong smell of gas - it was basically seeping through the exhaust. Just got the car back yesterday and it runs like a champ (so far).

Here's a vid I recorded of it. Maybe your problem is similar.

Mine isn't knocking as loud as yours, but time will tell if it gets worse. Hoping it's just carbon buildup on intakes or bad plugs. Injector sounds expensive

[CyberNate]

Hydraulic lifters bad. That's what caused the same symptoms on my car. If the lifters leak down, it takes a few seconds for them to build up pressure to fully open. took my dealer two months to figure this out.

[aesfah]

Update: I reset the air intake hose from air box to engine body bc I noticed it was loose. Now car doesn't shut off at cold start anymore and rough idle went away BUT new problem:

immediately after cold startup when I go put my foot on the brake to shift into D, the rpm jumps up and down from 600 to 1000. It keeps jumping so long as my foot is on the brake. Rmp issue goes away once in D and is fine until next cold startup. Any ideas at all?

[aesfah]

Bump. Anyone experience jumping rpms on cold startup when holding the brake pedal? It goes away when warmed up.

[arctic330i]

Originally Posted by aesfah

Bump. Anyone experience jumping rpms on cold startup when holding the brake pedal? It goes away when warmed up.

I have this, as in a cold start and immediately put into reverse and brake the RPM's surge and I lunge backwards. I thought it was crazy until my buds 330i did the same thing.

[TheZift]

I'm having very similar issues.
I'm starting to believe it's between the fuel pump or leaky injectors. Turning towards injectors because mpg is trash when driving modestly ~16 mpg as apposed to 19 before this mess.
I thought it was the the fuel pump but I can hear it priming and the car can be driven for long periods of time.

Bump for someone who found a real solution.

Btw: I heard there was a recall on injectors??

Originally Posted by aesfah

I've recently begun experiencing rough idle upon startup. About 5 seconds after firing up from dead cold, the RPM drops below 500, then goes up to 800, then car dies. I'll turn it on again, and it dies 5 seconds later. When I finally get it to run, it performs flawlessly - smooth revving and no rough idles. Any ideas on what could be wrong? I'm stumped and CPO ran out last year.

Car has 85k miles. Here's what I've have and what I've already done:

-cleaned MAF w/MAF cleaner.
-added Techron concentrated fuel cleaner with last fill-up
-changed gas stations - use only shell
-battery is 2 years old
-original starter, t-stat, water pump
-installed new plugs last year (10k miles ago)
-replaced 3 of 6 coils under warranty 2 years ago

Recently threw P0172 code (Mixture too rich). Did search, but not sure where else to go from here...

[TheZift]

Btw the only time it actually works is if you slam the gas while it turns over. Send it to about 2k rpm and it runs fine.

[Wilt]

Originally Posted by aesfah

Bump. Anyone experience jumping rpms on cold startup when holding the brake pedal? It goes away when warmed up.

A surging idle is often the indication of a LEAN fuel mixture. So the engine management tries to enrichen the mixture. It can mean an air leak into the engine from a variety of causes. In my E46 after about 12 years, it was a failed Cyclone Separator. When the engine is warm, it does not need as rich a mixture to run properly as when it is cold and idling.