Rough running when started

[haworthp]

I recently purchased a 95 318ti. Apart from totally refurbing the brakes and replacing the shocks, which were in a sorry state, I have the following problem with the car.
When starting from cold it fires up but then immediatley runs rough and dies when the accelerator pedal is pressed. This lasts for a few minutes until it starts getting warmed up, gets better until warmed and then runs totally fine. The car has started and run fine on one occasion, but once only.
This is what I have done up to now to try and cure the problem.
I have cleaned the Idle Regulating Valve and checked the hoses connected to the unit. Cleaned the Crank Case Vent Valve and checked connected hoses. Replaced the Remote Thermometre Sending Unit (PITA to do) and the intake rubber boot. Cleaned the air flow sensor. Removed each spark plug after being stood overnight to to see if there is any fuel leaking from the injectors, whether this is a good enough test I don't know. Cleaned butterflys etc on throttle housing.
Most of the above I have seen mentioned in other posts that could cause bad starting.
Has anyone any ideas or know of anything else that could cause this problem?
Any info would be appreciated as this is beginning to really annoy me!

regards

[central09]

sounds pretty fammiliar of whats going on with my car i went and got it diagnosed and they told me a BAd MAF and idle control valve just giving you a heads up

[haworthp]

central09, thanks for the reply.
Have you replaced the parts yet? My next step was to try another MAF. I have cleaned the ICV but it didn't seem to free it enough though. I'll take it off again and have another look.

[central09]

ya actually i bought a MAF from a junk yard the problem went away and so did the CEL but about 2 hours later the cel came on again idicating a BAd maf but its not running nearly as bad as it was ...tihnk i might have bought a bad maf


but my advice if your going to buy from a junkyard get a warranty for about 75 or buy new for like 350

i never did replace the icv yet so honestly it may be causing it all so yes i still need one !...

[haworthp]

I don't really want to buy a used MAF for the reason you mentioned, it may not be a good one. I haven't priced a new or exchange unit but I think they will be expensive. I'll take your advice and source a used one with a warranty.

Cheers

[oakley]

You can get new MAF's on ebay for around £40 dude

[gr8knurlin]

Info taken from an M3 board...might be worth a try

TECH: Clean your MAF, don't replace!

--------------------------------------------------------------------------------

NOTE: Late Breaking Update:
Read this entire thread before making the decision to clean your MAFs. Don't clean it unless you are experiencing problems. You might damage your MAF. Be aware that this process is not endorsed by BMW or by the Management of this establishment. These are delicate and expensive parts. Your mileage may vary. (end of disclaimer. read on!)


If you are having Air-Fuel mixture problems... Clean your MAFs.

Here's How

A couple of months ago my car started throwing a long series of fault codes, and lighting up the SES light.



Symptoms:
- at full throttle, like passing another car on an uphill, the Beast would drop into a limp-home mode.
- when idling it would occasionally stall
- car misfired and ran rough

Well, my dealer charged me 2 hours labor to investigate, eventually finding a vacuum leak, and then reset the fault codes. Well, $200 bucks lighter, the car threw more fault codes on the way home.

They suspected I would need to replace both MAFs. Cost? $407 per MAF. Yikes! And they weren't even sure that would fix it.

Well, I've been out of warranty for over 10K miles, so I didn't really want them spending more of my money to experiment with a fix. On their dime? Sure. On mine? Thanks, I'll do the experimentation.

So I bought a new MAF ($274 by mail) and swapped it in. Bingo! No more stalling, and runs much better at full tilt!

Well, I thought to myself, a while back somebody mentioned on the board that the K&N filter's oil had fouled their MAFs. I don't use K&Ns, but I'm sure after 60k miles there's some dirt in there. So I figures I'd clean out the old one and swap it back in.

All clean, replaced on the car... and... It Runs Great!

Dirt is your enemy.

Careful cleaning is your best weapon.

My solution might not fix your problem. Your mileage may vary. Blah, blah, blah.

[M4YTY]

sounds like a bad maf. Just unplug it and start it up. if it runs ok, you then know its the maf at fault.

[oakley]

Will it start with the MAF unplugged then??

[M4YTY]

Originally Posted by oakley

Will it start with the MAF unplugged then??

Yeah. Its will just run on a basic map. Had a 328 at work the other day with a bad maf. Cutting out after starting. unplugged the maf and it fired up no probs.

[thesk8nmidget]

could also very likely be a vaccume leak.

and also my 02 sensor caused a pretty crappy idle and intermittent check engine light

since you have a 95 you can run the cel codes with out a tool

http://www.318ti.org/forum/showthread.php?t=7211

[oakley]

Cool worth knowing! Thnaks mate

[haworthp]

Been on holiday for while. I will try unplugging the MAF and staring it and see what happens.
If I unplug it while running it just dies though.

Cheers

[M4YTY]

yeah. It needs an ignition cycle (turn it off then on again) to work. Unplug it, then try to start it. It may take a couple attempts.

[VROOMCP]

i just tried disconnecting mine and it started and idle'd fine after a few cycles. I guess my MAF is bad. Anyone know how to clean it?