M30 IDLE PROBLEM

[gall]

Hi,

i've got a problem in that my m30 won't sit at a steady idle, i think the idle is set to low 500/600 rpm.

any ideas what up with it??

cheers

gall.

[march109]

vacuum leak possibly? tried checking the pipes from the air intake to the engine for splits?

[gall]

cheers march109,

yeah that was the problem.

any idea what the idle rpm shold be?

how can i change it?

cheers
gall.

[march109]

replace the affected rubber pipe, bloody hard to find them in good nick second hand. Try the stealers but I've heard horror stories about prices of these, some gaffa tape should do it.

No idea on the RPM though they are usually around 600-700 rpm, my m20 idles at 600, fix the leak and you should fix the idle.

[Brianmoooore]

replace the affected rubber pipe, bloody hard to find them in good nick second hand. Try the stealers but I've heard horror stories about prices of these, some gaffa tape should do it.

No idea on the RPM though they are usually around 600-700 rpm, my m20 idles at 600, fix the leak and you should fix the idle.

Idle speed is fixed by the ECU, and can only be changed by reprogramming it.
Small increase in idle speed can be achieved (don't know why you should want to, though) by connecting the ECU pin that is switched for aircon.

[gareth]

the main M30 air hose i needed was only about £15 / 20 new... but i was given one for free by a splendid fellow 'zoner! (you know who you are... )

[oze30]

The air hose is part# 13.71.1.707.767 and its 12.43 Not sure if its plus vat or not.. just reading it from my invoice.

Mine's got no leaks, but still idles odd.

Cold start idles way too rich and lumpy. Sounds like an injector not squirting, but mine's not the only m30b35 that's doing it. When it's warm, its fine. not lumpy/rich.

Any ideas?

[Brianmoooore]

If you are sure there's no physical cause, then experiment with a resistor (start with about 2000 ohms) connected across the wires to the blue temp sensor.
This will reduce the amount of cold start enrichment.

[oze30]

How come it would cause an issue in an e30 when it doesnt in an e34?

[nickso]

The air hose is part# 13.71.1.707.767 and its 12.43 Not sure if its plus vat or not.. just reading it from my invoice.

Mine's got no leaks, but still idles odd.

Cold start idles way too rich and lumpy. Sounds like an injector not squirting, but mine's not the only m30b35 that's doing it. When it's warm, its fine. not lumpy/rich.

Any ideas?

exact same problem with mine.....sometimes it starts like a bag of nails other times it starts perfectly.

im beginning to think its a fuelling issue like brian said. ive changed the fpr as i had one handy but it made no change.

[gareth]

mine is/was spluttery from startup in both the E32 735i and E30. for the fist minure from cold (when idling) it's just a bit lumpy then it sorts itself out. it's something i have to address at some point if i ever get that bored but it never causes a problem with starting. in fact, mine has never failed to start after a very quick burst on the starter motor (less than 1 second, then i let go of the key and it'll be running). even after being dry of fuel when doing the swap, it fired after about 5 revolutions (2 seconds?).

well that's jinxed it!!!!

[oze30]

mine is/was spluttery from startup in both the E32 735i and E30. for the fist minure from cold (when idling) it's just a bit lumpy then it sorts itself out. it's something i have to address at some point if i ever get that bored but it never causes a problem with starting. in fact, mine has never failed to start after a very quick burst on the starter motor (less than 1 second, then i let go of the key and it'll be running). even after being dry of fuel when doing the swap, it fired after about 5 revolutions (2 seconds?).

well that's jinxed it!!!!

mine was the same. Started on the button after the swap. But cant work out why they do this.

Yet to try the resistor. Going to go to maplin tomorrow and see what happens.

[oze30]

So it goes across the wires, not inline with one? I think i biught the wrong ones.. i boutght 200, 270.. might have to return them and try again