Author Topic: warm start problems (Read 3679 times)

asmith88 · « **on:** June 15, 2009, 06:27:51 PM »

tried the above and didnt work, i have a 1990 e30 318is m42

has always started perfect from cold but once it ha been started the engine needs to be off for at least anhour before it starts perfect again.

what it does is "wobbles/stutters" when started it stutters down too 500rpm 2/3 times every time then idles perfect until started again, this in no way affects driving that i am aware off. but annoys the hell out of me as the rest of the car is mint and i dont want a wobbly engine

so far i have:
replaced air hoses (no air leaks)
replaced blue temp sensor
cleaned all intake manifold/tb/air flow meter inside

cant understand what could be going on..

any ideas fellas?

DesktopDave · « **Reply #1 on:** June 15, 2009, 08:17:37 PM »

Can you do a stomp test and let us know what the codes are?

Sounds like it could be a lot of things...dodgy fuel pump, bad check valve, bad AFM, bad O2 sensor, bad TPS, bad cam sensor...whatever it is that's failing, sounds like it hates being hot. When the engine is cool it runs perfectly. You didn't read this thread, did you?
http://www.m42club.com/forums/showthread.php?t=7757&highlight=hot+start

There's a little connector on the wiring harness at the middle of the firewall that's supposed to be unplugged if you have a catalytic converter installed.

asmith88 · « **Reply #2 on:** June 16, 2009, 04:07:26 AM »

yea tried the unplugging, just made things worse.

dont have access to a diagnostic machine.

AcSchnitzer318is · « **Reply #3 on:** June 16, 2009, 07:08:20 PM »

^If you have a US version car you are supposed to have that wire unplugged. And if you still had problems with it after unplugging it, you're o2 sensor probably needs to be replaced. Try unplugging and possibly a new o2.

DesktopDave · « **Reply #4 on:** June 16, 2009, 09:06:51 PM »

You don't need a diagnostic machine with this car if it's US spec...do the stomp test. Turn the key to position 2, don't start the car, rapidly press the gas pedal all the way to the floor five times within five seconds. It's hard to get the timing just right, but keep trying...it'll work.

I know it sounds stupid, but then the CEL will start blinking codes at you. It's not gospel truth, but it can really help out at times. I'll bet you see a 1221 lambda sensor code from the O2 sensor. You can splice in a cheap Ford Mustang one to replace it.

Google 'BMW stomp test' and something like 112,000 pages will give you the codes & more detail. This computer was installed in a ton of BMWs, they all work the same way until OBDII in 1996.

asmith88 · « **Reply #5 on:** July 01, 2009, 06:17:47 PM »

its the europeon version, have just replaced the air flow meter and tps, and although the car seems to drive a lot better now the revs just seems to continuously hunt between 1100 and 800 on idle

bloody car, i dont want to go to a garage because they rip you off in labour charges but im getting to the stage where i think thats the only way to do it..

DesktopDave · « **Reply #6 on:** July 01, 2009, 08:08:29 PM »

Did you clean/test the ICV? You're going through all the steps I'd do. That's the only one I didn't see mentioned.

Some other BMWs have a warm start problem because of a bad check valve in the pump. Might be worth checking out. I'd also suspect cracked spark plug HT leads.