Dodgy Cold Start!! AHH!!

[geo1400]

I've had this problem for a while and just tinkered away trying to figure the problem by changing things.

The Symptoms: If the car sits for more than 2 hours(approx), its struggles to start. It will turn over for about 6 -7 seconds then cough splutter and kick in. Then the idle is really rough unless I give it a little throttle. Once it's cleared its throat its runs real nice. And if I turn the engine off straight after the struggled start, it will start again first turn!

What I've done:
Second Hand ICV (made a huge difference in the idle) along with with new piping surrounding the ICV.
New Starter Motor
New Ignition Leads
Recent Service
New Belts
Second Hand Fuel regulator valve
New blue temp sensor
Inlet and manifold gaskets (also done a search for air leaks)
A few other things that i've forgotting about...

Anyone any ideas? please help it hurts me every time I hear my motor struggle?

Geo1400

[TouringMatt]

What idle speed do you get on a cold engine?

What engine BTW?

Matt

[geo1400]

Once it's coughed and spluttered it idles about 1000rpm for a little while and then it settles at about 800rpm.

What does BTW mean? it's gonna be really obvious I know but i'm a bit dense.

I did forget to mention it's a 318i - M40

Cheers Matt

[Gortour]

BTW = By The Way

[geo1400]

Ta

[TouringMatt]

I had the same problems and replaced the same things, with equally similar results.

Eventually checked the round wiring multiplug that sits roughly under the inlet manifold and found one wire was bent over and partially broken, this wire was the one that ran from the blue temp sensor to the ECU, hence nothing working right. Replaced the wire (fiddly feckin job) and problem cured, idles at around 1200 when cold, settles to around 800 when warm and no spluttery start.

Only thing is this is on an M20, not sure if the M40 has the same plug............ if you handy with a multimeter you could do a few checks for resistance i guess!

HTH (hope this helps )

Matt

[geo1400]

Thanks for that information. I was chatting to a mechanic yesterday and he said check the plug that goes into the AFM, clean it up etc. This could be similar thing, i'll trace the wiring from the blue temp sensor as well.

Anyone else have any idea where any dodgy wiring could be?

Cheers

[Brianmoooore]

Sounds like an injector is leaking fuel into the manifold while parked, giving an over rich mixture on start up.
When you park the car, stop it by pulling out fuse 11 (fuel pump), and see how it starts after a couple of hours.
It will take longer to start than normal because the fuel rail will be unpressurised, but then, if I'm on the right track, will idle cleanly.

[geo1400]

Ok, given it a couple of days now footering about. Stopped the car by removing fuse 11 and ended leaving it for a day. Started it up and it was great! it actually started quicker and then settled better, just like you said it would Brian!

So after that journey, pulled the fuse again and left it all day. The next start up was a bit of a struggle BUT did settle quicker. The one thing that was still there which is related to a cold engine was when I reved it up, there was a very slight pause/hesitation before the revs increase.

Basically Brian, I thought you'd absolutely nailed it after my first fuse removal because it was sooo much better. But the second time put doubt in my head.

You still think it is a leaking injector?

Cheers again,

Geo1400

[autobahn_stormer]

talking about plugs to the AFM, mine has the large screw in plug to the AFM but also attached to the same mini-loom is another small connector that isnt connected to anything, what does this do!?

[Brianmoooore]

, what does this do!?

Solenoid valve for charcoal canister, which you don't have, so don't worry about it.

[geo1400]

I've got that as well. I think its used for plugging computers and stuff into. Doesn't do anything as far as i'm concerned, unless someone can tell me it helps to start an M40?

[Brianmoooore]

You still think it is a leaking injector?

Probably, but not necessarily the only problem.

[geo1400]

Brian you were quicker than me there, I now know its nothing to do with computers and stuff!

What do you think about my starting problem? still injectors?

[Brianmoooore]

Posts are all getting out of order here!

[geo1400]

Done it again, sorry. You can do a check on injectors can't you? I'm sure I've seen it in Haynes.

[geo1400]

Right, i'm gonna throw something else into the mix, my car generally runs like s**t before the the temp gauge clears the blue bit. After starting poorly it nearly stalls at the biting point and hesitates in low revs?

Any ideas?

Brian if you read this, I haven't taken the injectors apart yet cause I thought I'd narrow down the symptoms, or find more!

[geo1400]

bump

ok this is the last time i'l bump this to the top, i'll just have to live with my dodgy cold start...

[Ant]

replace the blue coolant temp sensor and try again dude.

[geo1400]

Hi Ant, I done that! that's the one that sits under the inlet Mani isn't it?

Someone recommended that when I was first having the probs and it didn't solve anything. There were a few fidly plugs under there though, I wonder if i've nor reconnected something properly...

Going mad

[geo1400]

Right ok. This is it... Someone must have an idea after this...

Decided I would take out my fuel pump relay (which I put in new about 18 months ago), and put my old one back in. And I could not believe it, the car started first turn for 2 days!!

Then for no reason at all, starting the car after work yesteday - back to the same old s**t!!

WHY IS IT DOING THAT?

This is the last time you'll see this post, promise

[Martinaston]

It may sound a daft question but have you checked the oil level ?
and how many miles on the engine ?

[geo1400]

I check the oil all the time. The cars done 112,000 miles. How could the oil level affect the starting?

[Martinaston]

If you have low oil pressure it won't start, so i was just wondering if you were parking uphill one day and downhill the next. I take it the oil lightbulb's not blown then.

You mentioned that it was serviced so i assume that was a new air filter as well ? take it out if it looks suspect.

It seems odd that it's ok for a few days and then plays up again damp days perhaps ? could you lend another ecu to try incase yours has started to rust ?

[geo1400]

Not sure about the oil light .

I have suspected the ECU cause I replaced that with a 2nd hand one when I got the car because the original was corroded. And I got a diagnostic done about a year ago and they said there was a fault in the ECU, just couldn't tell me what it was??

What about the fuel pump? I find that quite noisy, but nothing to compare it to.

So many things...

[Martinaston]

One step at a time then.

[geo1400]

Yeh i know, problem is i'm bloody knackered cause I've taken so many steps!!

[Martinaston]

Just noticed where you are, so at a guess i'd say go through all the electrics and check for corrosion.
Best of luck, gotta go.