Cutting out on idle

Post Wed May 11, 2005 8:38 am

Had what I thought was a major electrical problem with the car that I thought was linked to the twin immobilisor system that's installed. Car just didn't have any power, but shut the door and it triggered something that gave the car power, but start it, and the ignition would click and power would die... nothing, no lights, no nothing... a loose wire I thought... had the whole lot out, bloody nightmare!

Ended up being the earth lead was loose on the battery in the boot. Doh!

So, put it back on, tightened it up... and now I've got another problem. When the car's idling, it cuts out. Great when you come to a stop while driving... bang, she's gone. A special bit of heel and toe-ing is going on at the minute to keep the revs up when coming to a stop.

Just need someone to re-assure me it's the ECU playing up after the power was disconnected and that it will right itself soon... please!

Giles.

Post Wed May 11, 2005 11:45 am

well to comfort you that's EXACTLY what happens on my 1989 325i. Disconnect/reconnect the battery and for the first 2 or 3 journeys, it cuts out at junctions.

But it is only 3 short journeys, then the system seems to say 'oh I'm supposed to keep the engine running am I? Ohhh now I remember...'
and the problem has gone, never to return.... until you disconnect the battery again doh!

Post Wed May 11, 2005 1:22 pm

Hmm... done it for more than three journeys now though... Just keeping my fingers crossed that it'll sort itself.

Post Wed May 11, 2005 2:34 pm

It should in theory reset itself while idling for about 10+ mins, just keep trying to start it from cold, and see what happens don't drive though.

Post Wed May 11, 2005 11:37 pm

Still doing it 3 days on...

So tonight, I've parked the car up the drive and disconnected the battery again. This time, tomorrow morning when I re-connect it up, I'll just leave it running in the drive at idle, instead of driving it like I did before.

Hopefully this should cure the cutting out. As it is now, even when I start her up from cold, she won't idle at all. A little pressure on the accellerator to bring the revs up to 800ish and it sits there fine, but take my foot off and it dips and dies... Grrrrr!

Fingers crossed...

Post Thu May 12, 2005 12:10 pm

A little pressure on the accellerator to bring the revs up to 800ish and it sits there fine, but take my foot off and it dips and dies... Grrrrr!

doesn't sound like electrics to me,
i would start looking at fuelling mixture,split pipes, sucking in air

Post Thu May 12, 2005 1:28 pm

Yeah... but it's coincidental that it happened straight after the battery was disconnected.

Tested it this morning. Had the battery off all last night, connected it up this morning, started the car (no touching of the accelerator pedal) and it struck up first time and sat at 700rpm. Left it for 15 minutes at idle, no problems. Then got in the car, touched the accelerator pedal, the revs increased, took my foot off and it dipped and died. Grrrrrr! Now it's doing it all again.

I've got round it by screwing in the idle speed control screw in, so now it sits happily at just over 600rpm.

Maybe after a few journeys it'll sort itself out.

Post Thu May 12, 2005 1:43 pm

doesnt sound like an ecu fault-cos if it was the car would be rough throughout the rev range...

think Glenn is on the right track...

the 525i i just got would idle but not rev-getting too much air when revved.Turned out to be a split in the air-filter to TB pipe.

as yours wont idle, its prob either getting too much fuel (and flooding) or not enough air (running too lean)

i'd check that the flap on the TB was letting air through when 'closed'

or it could be the cold start injector staying on and flooding it?!

Post Thu May 12, 2005 3:30 pm

How do you check the TB flap is letting air through...?

Post Thu May 12, 2005 3:56 pm

Geeman wrote:How do you check the TB flap is letting air through...?

take off the filter hose and try to fit a feeler gauge between the butterfly and the body of the TB...

should be enough clearance for about a 0.25 thou gauge.... on the side that opens IN (towards the engine (iirc)

Post Thu May 12, 2005 5:21 pm

I take it you do this with the engine turned off!

And if it's not letting air through... how do you adjust it?

Post Thu May 12, 2005 5:27 pm

I admit it's coincidental that its only happened after you disconnected the battery,but TBH I doubt very much it's linked.
I've taken batteries in and out of my Tourer to start the Herald or the Tranny frequantly and never had any idle issues at all,car just starts and runs as normal everytime after replacing it.

Post Thu May 12, 2005 5:27 pm

Geeman wrote:I take it you do this with the engine turned off!

And if it's not letting air through... how do you adjust it?

yeah off is best

sould be able to loosen the rod holding it and move it round until you get enough of a gap...

Post Thu May 12, 2005 5:45 pm

There is an adjustment screw on the TB.

I don't think the engine will run with the TB boot off, it might but not very well.

Post Thu May 12, 2005 5:49 pm

Andy_magic wrote:There is an adjustment screw on the TB.

I don't think the engine will run with the TB boot off, it might but not very well.

just meaning for him to check the gap with the pipe off so he can see it,

then reconnect the pipe and try starting it-

should idle ok if set to correct level.

thanks for pointing out that my post wasnt too clear

Post Thu May 12, 2005 5:51 pm

Sorry mate, that last post wasn't meant to sound arsy.

Post Thu May 12, 2005 5:54 pm

Andy_magic wrote:Sorry mate, that last post wasn't meant to sound arsy.

i was meaning thanks!!!! i re read it and saw what you meant-thats why i posted to clear up what i'm saying

would have put

instead of

if you'd 'sounded arsy'

genuine thanks for that!

Post Thu May 12, 2005 7:37 pm

that fingers up

icon is pretty cool, I can see me having to use that when people take the pi55 out of my motor.