idles up and down

[ravstar13]

Hi Guys,

my 325i mooredoor has all of a sudden developed an up an down idle, when I pull off car drives lovely stationary it does all that fluctuation, even cut out a few times, but starts up fine again. Could the MAF need replacing?

[Quaser]

check for air leaks in the rubber elbow

[Quaser]

check for air leaks in the rubber elbow

[ravstar13]

Thank you for that ...ok i will have a look later...if its not then what should i be looking at?

[Yeti]

idle up and down is due to an air leak as the car compensates then stops as it reaches the correct idle but when it stops the idle drops then it starts the cycle again .

can of brake cleaner/carb cleaner around the inlet/hoses etc. and listen for the engine to change note as that will indicate a air leak.

[Doobit]

Usually it's air leaks, check the boot first. Could be fuel (check/change fuel filter) could be icv, could be an injector issue or a sticky throttle position switch. But far less likely. Possibly the blue plug controlling the fuel input via motronic.

Boot first, then fuel system....and read the wiki it's good fir troubleshooting idle problems.

[ravstar13]

Cheers guys, I will defiantly check all these ...hopefully its just that.

[ravstar13]

cheers guys !!! there was a hole/tear under no couldnt see it at first, you are all legends!

[ah]

Sorry where was the hole/tear.

[ravstar13]

it was on the rubber boot from the MAF..it was in between the ridges.

[steve_k]

it was on the rubber boot from the MAF..it was in between the ridges.

ihad that, took it off & slung it over the hedge (next door must love me ).

i replaced it with a silicone elbow & a take off from revotetec for the ICV.

no more air leaks round there.