E34 535i Diagnostics

[mattyp]

Hi guys

Recently I acquired an E34 535i '91 model with about 128,00 kms. Immaculate, well looked after and runs like a dream ***but***

I've noticed very occasionally that at lower revs and idle (say as I've slowed right down and about to stop when pulling up at a red light).

It will seem to start idling too low, with the car (assuming throttle control - methinks from memory this car/engine has one) trying to rev a little so it doesn't stall. Once I'm driving normally or opening her up all is good.

This leads me to think it may be one of the following, but am interested to see what u dem expertsd out in der teknical lands thinks (trying to mimic Cletus the slack jaw yokel ):

Simple stuff that might be worth checking/replacing??

Fuel filter or even fuel pump

What I think is more likely:

AFM (wanting to get it replaced with a MAF and corresponding chip soon anyhoo).

Computer/software (I'm assuming that replacing the chip will fix this if it is indeed a computer problem, unless the issue is more terminal?)

O2 sensor or even temp sesnor (I believe if one of either is out or playing up the car will run like crap) or wiring of.


What I would like to do is get a code reader (and am wondering where I can get one, approx $$$ ertc) so I can see exactly what the OBC is saying and try some simple troubleshooting myself first (I have a service reset tool but it only resets, can't read codes or anything).

Any help or suggestions would be greatly appreciated.

Thx,

Matt.

[pcross]

Could be simpler than you think....A very dirty air filter causes exactly the symptoms you speak of. Can't hurt to check.

[mattyp]

Could be simpler than you think....A very dirty air filter causes exactly the symptoms you speak of. Can't hurt to check.

Hi pcross

That sounds like a very good idea, will do so tonight "

Thanks very much for your help mate. :thumbs

Cheers,

Matt.

[Adnan]

Hi,

Assuming the car has an idle control valve, pull it out and give it a thorough cleaning. If you have the M30 engine, that's a distinct possibility.

Regards,
Adnan

[JMI]

See Stumbles at Idle
and Idle Control Valve?

Somehow I posted the above to wrong thread last night.

Good Luck

Jim

[rob101]

JMI that pulse sensor you're talking about in that thread of yours, is that just the Cam Angle sensor?

[JMI]

JMI that pulse sensor you're talking about in that thread of yours, is that just the Cam Angle sensor?

It determines when #6 fires so I guess it knows the cam angle.

Jim

[mamilapon]

Hi pcross

That sounds like a very good idea, will do so tonight "

Thanks very much for your help mate. :thumbs

Cheers,

Matt.

A throttle body thats full of crap. Pull it out and give it a good clean with carby cleaner, same with ICV good luck matey!

[mattyp]

Thanks very much guys for all of your help

I'm going to pull the carby cleaner ourt and give the ICV and throttle body a good cleaning this weekend & will let everyone know how I go next week.