Small Problem with '99 e39 528i

[tdm34ds]

When the car is first started in the morning, as it's warming up it misfires almost stalling
every now and again. When it's fully up to working temp it's perfect, also if I drive off from cold
it doesn't miss a beat. It only does it if I leave it to warm up before starting my journey. Any ideas??
thanks

Regards Rob

[tdm34ds]

bump

[Neil.D]

You dont need to bump brother...can just be a little slow on occasion, or potentially the right person hasnt got home from work yet.

Cold running problems are normally caused by a faulty sensor. Not rocket science I know but the engine 'learns' its values from the Mass air flow sensor, O2 sensors etc.
If one of those is on its way out then the 'learnt' values are wrong. This is exaggerated when the car is cold as it does not adapt to the sensor readings whilst on the move. It simply guesses what fuel mixture etc according to outside temp and the MAF reading. O2 sensors do not kick in until the engine is 70C or so which is why it may run fine when hot.
I would start by cleaning the MAF sensor - http://www.louv.tv/cars/m5/MAF/ - if that doesnt help pop into your local specialist for the diagnostics machine to see if you have a failing sensor as described.

Neil

[tdm34ds]

sorry about that Neil sounds like a visit to a dealer or indie then

[Neil.D]

I suggest BMW specialist. The dealer wont take half as much care as a reputable specialist would.

Just my advice.

[phelix]

Does it idle fine for the first 30 seconds or so and then hunt, dropping so low that it almost stalls and then it finally does?

[sniff petrol]

Could be a bit of dirty fuel - when was the filter last done? Failing that try a bottle of injector cleaner and a nice fresh tank of V power.

[tdm34ds]

phelix said:

Does it idle fine for the first 30 seconds or so and then hunt, dropping so low that it almost stalls and then it finally does?

As you describe it except it doesn't stall (just threatens to do so) the cars just had a full service at an indy I use (all filters etc) the problem was evident before the service.

Regards Rob..............

[phelix]

Sounds like the seals in the VANOS (variable cam timing). I have a 99 328i with the same engine; replacing the seals solved the problem. Parts are cheap (£40) but about 5 hours to fit. Now idles v smoothly again. See http://www.beisansystems.com/

[tdm34ds]

phelix said:

Sounds like the seals in the VANOS (variable cam timing). I have a 99 328i with the same engine; replacing the seals solved the problem. Parts are cheap (£40) but about 5 hours to fit. Now idles v smoothly again. See http://www.beisansystems.com/

I'd hoped it wasn't this, but after reading it properly it sounds very much like this is the problem!!

But after reading the repair procedure I feel confident enough to attempt this myself the attention to detail by it's
author is unbelievable.

Has anyone on PH ever used this kit and if so is there anyone who can offer any other pearls of wisdom.
Or is there any PHer in the Manchester area who could recommend an indy who'd take on the Job at a
reasonable cost

Regards to all who've offered advise

Rob.............

[phelix]

tdm34ds said:

Has anyone on PH ever used this kit and if so is there anyone who can offer any other pearls of wisdom.

I did the job about 8 weeks ago and as you say the instructions are very thorough. Definately replace the gaskets and seals mentioned; the valve cover gasket was hardened to the point of being very brittle.

[tdm34ds]

phelix said:

tdm34ds said:

Has anyone on PH ever used this kit and if so is there anyone who can offer any other pearls of wisdom.

I did the job about 8 weeks ago and as you say the instructions are very thorough. Definately replace the gaskets and seals mentioned; the valve cover gasket was hardened to the point of being very brittle.

Thanks for the info phelix the car doesn't lack power as yet so i'll leave it a
while. When the symptoms become more apparent i'll get the kit and sort it

Regards Rob.............

[phelix]

My car never lacked power and doesn't feel any different after the seal replacement other than the idle problem being gone so you may be waiting some time...