bmwe21.net forums

Well, my Baur has started to tease me when cold. Mostly when not started for some days. Thing is that it starts at first but then dies again at once. It can do so for abt. 10 times and then it runs just normal. I can allso hold the starter on for abt. 10-15 secs. and it will keep started. My first thought was the fuelpump relay but it was not. I am now thinking cold start injector or maybe fuel pump? Any ideas?

On this video I was lucky that it started on second try (the car was started yesterday). You can hear the pump running after the engine stops.

http://youtu.be/cF5oZCWL7Vg

On the video, it looks like first try you hit the gas pedal, and that killed it, but the second time you didn't, and it started, would that be correct?

If so it might well be the cold start valve not working, so the car is starting lean, and opening the throttle is making it even leaner and the car dies. Unplug the cold start valve and if the symptoms are unchanged, it's a good bet that's your problem.

Thanks for your input!

No, I am not touching the pedal at all...

Looking at the RPM when she is running cold the extra airvalve is reasonably OK.

The cold startinjector could be the on but you can try first if your temperatureswitch is giving the right info to the cold startinjecteur. If it is broken there is no info that the engine is cold and the injector is not working at all.

This one is located at the thermostathousing and has the bosch connection. If you connect both pins together the cold start injector is working. If the car runs at once and stays running then it is that switch. Make sure to remove the connection between the pins quickly or you wil put to much petrol in it.

After the car is sat for a couple of days, it needs several attempts or one long attempt before it runs. But if it starts up, it runs fine. Imho that rules out the cold start injector (even though Peter's suggested tests are easy enough to rule that out) or the warm up regulator as in these cases the car would start up very slowly starting at low revs. Correct me if I'm wrong!

So I'm thinking that with this happening after days, fuel runs back in the lines. Could not be a leaking injector or it should be likely to start on 5 cylinders. So I'm thinking a non return valve in the fuel pump staying open, does that make sense guys?

What exactly is the function of the fuel accumulator, could that play a role? What I know is that these things mainly stabilize fuel outturn and if they break you won't get fuel and have a non starting car, don't think that has a valve in there, or?

Because the remark is that the actual start is fine but it wil not keep running looks like there is fuel comming but to less to keep the cold engine alive.

I always thought that the accumulator keeps the pressure on the system for a long time. When the K-jet is started after two days it must run instantly and not aftrer several attempts (my opinion).

That is why I believe the lack of (initial) pressure is the actual problem and either the pump or accumulator may the the culprit.

Anyone who can tell what exactly the fuel accumulator does?

Have tried another pump, but still the same.

The accumulator retains pressure in the system when the pump isn't running, so you have full fuel pressure the moment you crank. It's just a chamber with a sprung loaded diaphragm.

With this current cold start issue (starting after several attempts or one long attempt) this may very well be defective then?

Must go and buy a new one then. Thanks!

Hope this is it, keep us posted!

Hi again!

Now with a new pump, but still the same...Thing is that my dealer says that they can't no longer sell me a new accumulator?? Can't be true?

Well - I write this post in hope that someone in the meanwhile has experienced similar issues - and maybe it is course of something else?

Thanks!

New video:
http://youtu.be/aKs03KPdQSs

Still sticking to my initial thoughts meaning no fuel. I believe Gerrit had similar issues and just deleted his accumulator. Can't do any harm to try! And if your new pump has a built in non return valve it is likely to be fine without.

No doubt the accumulator is the issue! Found this on k-jet.org. Just to be sure. The accumulator and CPR is the same thing - right? Does anyone have a partnumber on it?



1) Control pressure too high (Control Pressure Regulator) The control pressure changes as the engine warms up. The pressure is created by the Control Pressure Regulator (CPR). The CPR has a lower pressure on the control plunger in the fuel distributor when the engine is cold compared to when the engine is warm. The lower pressure allows the control plunger to let more fuel into the engine when the engine is cold. If the control pressure is too high, the air/fuel mixture will not have enough fuel, and thus the engine will not start.

The common symptom with a bad control pressure regulator is that the engine takes about 20 tries to start, each time idling for a little longer after it starts. Basically, you turn the key, the rpms go up to about 1500 – 2000 when the cold start injector fires, and then the car dies because it is not getting enough fuel after the cold start injector shuts off. Also, a bad control pressure regulator can make the engine almost die when you shift in to neutral (auto trans.) or depress the clutch pedal (manual trans.)