Idle control - HELP!!!!! - NOW IT WONT F'ING START!!!

[massive]

Start from the begining.

1991 325i sport

Had earlier M20B25 engine installed and started to have idle problems. would rev up for no apparent reason. and would idle at 1500.

Cleaned ICV and jubliee clipped hoses for air tightness. This made it a little better, nearly cured it. But every now and then it would idle high again....but a little rev and it would settle until the next idle.

Today I took off and cleaned with carb cleaner, ICV, throttle body, AFM. Put it back together and its WORSE. Idles at 2000rpm now

Whats going on??? Anyone suggest anything?

[massive]

Also what does the cable from the throttle body connect to? because its not plugged into anything

[Quaser]

ecu?

[cliffybabe]

i had the same sort of thing have u check the rubber boot for cracks etc???

[massive]

i had the same sort of thing have u check the rubber boot for cracks etc???

checked that mate and it all looks fine

Cant understand how i can make it worse from cleaning it

[tannerman8807]

Same prob, ie replaced ICV (new) Throttle switch, all pipes, and it will still idle at 900. Disconnected bat for 1 day and wala perfect for about 10 miles then back to its old trick.
Think im looking at ECU

[massive]

900 is correct idle isnt it?

[gasboyjay]

900 is correct idle isnt it?

yeah should be about 900. Have you fixed it now? did you check the air flow meter flap isn't sticking?

[massive]

No mines idling at 2000rpm at the moment. Was 1500rpm before I cleaned it.

The flap is fine its clean as a whistle!

What the screw on the throttle body do, its not even touching the accelerater mechanism thingy and its still reving its bollox off

[cliffybabe]

U haven't got a dogy air filter have ya??

[gcorky]

what does it do when you unplug the icv?hose from tb to servo -are these ok .

[sajid1]

i thing the idle control valve is sticking, change that it should solve it, or before u change it give a tap a few times , if it releases the revs should change/come down, hence you know its that

[massive]

U haven't got a dogy air filter have ya??

Air filter is standard

[gcorky]

No mines idling at 2000rpm at the moment. Was 1500rpm before I cleaned it.

The flap is fine its clean as a whistle!

What the screw on the throttle body do, its not even touching the accelerater mechanism thingy and its still reving its bollox off

missed this the arm should be resting on the stop bolt.has the cable outer moved from its grommet,disconnect cable does it rest...if not remove boot and inspect throttle butterfly...it should be allowed to close without obstruction...

[massive]

what does it do when you unplug the icv?hose from tb to servo -are these ok .

Not tried unpluging the icv whilst running. what should happen when i do?

All hoses are in good shape, not signs of wear or cracks.

[massive]

i thing the idle control valve is sticking, change that it should solve it, or before u change it give a tap a few times , if it releases the revs should change/come down, hence you know its that

Ok will try this too. Thanks

[gcorky]

what does it do when you unplug the icv?hose from tb to servo -are these ok .

Not tried unpluging the icv whilst running. what should happen when i do?

All hoses are in good shape, not signs of wear or cracks.

well from that speed, the engine should slow down if it was an icv/ecu problem-basically by disconnecting you are eliminating depending on outcome.

but check my above post,sometimes if you manually move the throttle arm -the cable can come out of its guide and not sit properly -then holding the throttle open,got a pic of the top of your tb arm/stop???

[massive]

No mines idling at 2000rpm at the moment. Was 1500rpm before I cleaned it.

The flap is fine its clean as a whistle!

What the screw on the throttle body do, its not even touching the accelerater mechanism thingy and its still reving its bollox off

missed this the arm should be resting on the stop bolt.has the cable outer moved from its grommet,disconnect cable does it rest...if not remove boot and inspect throttle butterfly...it should be allowed to close without obstruction...

It doesn't rest on the bolt when the throttle cable is removed from arm....however dick head here f**ked about with the screw...i know .

The butterfly was closing and clicking fine when I had it off earlier.

[massive]

what does it do when you unplug the icv?hose from tb to servo -are these ok .

Not tried unpluging the icv whilst running. what should happen when i do?

All hoses are in good shape, not signs of wear or cracks.

well from that speed, the engine should slow down if it was an icv/ecu problem-basically by disconnecting you are eliminating depending on outcome.

but check my above post,sometimes if you manually move the throttle arm -the cable can come out of its guide and not sit properly -then holding the throttle open,got a pic of the top of your tb arm/stop???

I'll take a photo now - thanks for this guys.

[massive]

Ok,

Started it up, run just over 1000rpm then as the seconds ticked it was upto 1700rpm. Unpluged the icv it did nothing. I gently tapped the icv with my mobile phone and it was dropping a bit then going straight back up....icv is f**ked you think??

[gcorky]

maybe-but is the throttle closing properly ?

[massive]

PIC one = birds eye view


PIC 2 = Side view showing the bolt thing (cable disconnected)

[gcorky]

looks like throttle is closed-ok there then(stop is out of adjustment-you say you altered it.
ok -unplugging icv didnt alter idle -ok to determine if icv is the culprit -pull the hose from the throttlebody that connects to the icv -run vehicle and plug the throttle body with your finger(where you pulled hose from0if icv is problem the car will stall or struggle to idle.


let me know.

[massive]

Wicked, i'll try that tomorrow morning.

Thinking about it though, when the throttle body is off the car it clicks closed and clicks open. I cant hear that once on the car...is this normal (i swear i used to be able to hear a few months ago)

[gcorky]

should hear it faintly .try that (above)if does as said get a used unit put on.if it doesnt alter with the icv unplugged and blanked youve got an airleak somewhere....keep us informed..
speak soon m8.

[massive]

looks like throttle is closed-ok there then(stop is out of adjustment-you say you altered it.
ok -unplugging icv didnt alter idle -ok to determine if icv is the culprit -pull the hose from the throttlebody that connects to the icv -run vehicle and plug the throttle body with your finger(where you pulled hose from0if icv is problem the car will stall or struggle to idle.


let me know.

gcorky,

Did the above as you advised.

Pulled the hose out from the t/b, and started engine. It wouldnt run idle like that, had to give it a couple of revs. However whenever i blocked the whole it cut dead immediately. I repeated this a couple of times with the same results.

would this idicate towards the icv then?

thanks

[DaveD]

900 is correct idle isnt it?

yeah should be about 900. Have you fixed it now? did you check the air flow meter flap isn't sticking?

6-800rpm...have you adjusted the afm? to compensate before you claened the icv.....have you had the throttle body off and not replaced the gasket

[massive]

mines way out then, still idling at 1700rpm. But if you tap the accelerater it goes down to 1000rpm but straight back up next time its at idle

I had the afm off and cleaned it....how do you adjust that?

Throttle body has been off and cleaned and definately put the gasket back on.

[massive]

Update on this:

Changed the ICV with no change

Also it appears that when the engine is hot it is allot worse. Anything else i can do?

[Ant]

dude, got your PM

so the inlet and ICV etc are from the CARS original engine yes ? does the TPs work correctly ?

has anyone tampered with the throttle stop screw ?

you 110% there are no intake side leaks, in particular the underside of the TB has a blanking pipe on it, if this has come off, or been torn in the swop it will pull a lot of air through the 5mm pipe fitting.

it will be something simple, these things always are....... ish

[Steviec]

Just a simple check.... do you have a set of mats in your car?
In my last car my idle was over the top and the car was accelerating for no reason and getting a bit worrying, so I cleaned things up but still had the trouble, it turned out that my drivers mat was pushing the bottom of the accelerator pedal. Pulled the mat back and all was fine.

[deian]

first thing check thatthe ICV it's actually working, put the ignition on but don't start the engine, it should hum a bit,

have you checked the wiring to and from the ICV? maybe there is a loose connection somewhere, lets not dismiss the obvious here

the wiring harness should be ok from the ecu, failing that the ecu is getting signals to adjust badly, if someone can work out why it does this then the ecu will deal with the ICV in an appropriate manner, oxygen sensors measure mixture, i believe being a 1991 model yours would have an oxygen sensor, if this is bad then the ecu will be adjusting the idle based on the oxygen sensors reading, especially when cold.

how is it when it's warmed up?

[massive]

dude, got your PM

so the inlet and ICV etc are from the CARS original engine yes ? does the TPs work correctly ?

has anyone tampered with the throttle stop screw ?

you 110% there are no intake side leaks, in particular the underside of the TB has a blanking pipe on it, if this has come off, or been torn in the swop it will pull a lot of air through the 5mm pipe fitting.

it will be something simple, these things always are....... ish

Hi Ant,

Thanks for your reply,

Yes the inlet, TB, ICV from the car's original engine.

Sorry what's a TPs?

I did fcuk about with the screw once but even when its undone and not even touching the acceleration arm its reving at 2000rpm idle.

It seems that when you change gear the revs take ages to drop, then float around the 1700-2000rpm mark. Sometimes a little rev of the engine will make it drop to 1000rpm but not always.

Ive checked and double checked the elbow hose, icv hoses for leaks.....but will double check again including the 5mm one you suggested.

I'll take it all apart again tomorrow and go through it all with a fine tooth comb.

Thanks

[massive]

Just a simple check.... do you have a set of mats in your car?
In my last car my idle was over the top and the car was accelerating for no reason and getting a bit worrying, so I cleaned things up but still had the trouble, it turned out that my drivers mat was pushing the bottom of the accelerator pedal. Pulled the mat back and all was fine.

Wish it was that simple mate, but the mats are held in position and not touching the acc pedal.

Thanks for your help.

[massive]

first thing check thatthe ICV it's actually working, put the ignition on but don't start the engine, it should hum a bit,

have you checked the wiring to and from the ICV? maybe there is a loose connection somewhere, lets not dismiss the obvious here

the wiring harness should be ok from the ecu, failing that the ecu is getting signals to adjust badly, if someone can work out why it does this then the ecu will deal with the ICV in an appropriate manner, oxygen sensors measure mixture, i believe being a 1991 model yours would have an oxygen sensor, if this is bad then the ecu will be adjusting the idle based on the oxygen sensors reading, especially when cold.

how is it when it's warmed up?

deian,

Yes the ICV hums.

Although its a 1991 car it has a early M20 engine in it. It was fine before the change over which makes me think Ive not swapped something over which is effecting the idle. Hoping I can find a air leak somewhere.....

When its warm its 10 times worse.