m20 2k - 3k idle

[steve_k]

hi folks, looking for a bit of help.

after sorting a non starting issue on my m20 (knackered HT lead) i now have a very high idle.

when i first got it started it idle'd at about 900 give or take 10%, then today when i come to start it, it idled at 3K!!!

i've checked for air leaks, there's none, all the hoses are new, i've checked the ICV, & sprayed it with carb cleaner to clear it out.

any other ideas??

[Steve]

TPS, blue temp sensor, AFM?

[davidt]

When you open the throttle can you hear a click from the TPS, also check that the connections on ether side of the throttle body that the servo and idle valve pipes fit to have not come loose, as it sounds like an unmetered air issue have a look at the breather hose from the cam cover to throttle body and one more thing is the oil filler cap on nice and tight.

[steve_k]

TPS, blue temp sensor, AFM?

TPS is clean and dry, AFM is as new (refurbed) as for the blue temp sensor is there a guide on how to check it?

[steve_k]

When you open the throttle can you hear a click from the TPS, also check that the connections on ether side of the throttle body that the servo and idle valve pipes fit to have not come loose, as it sounds like an unmetered air issue have a look at the breather hose from the cam cover to throttle body and one more thing is the oil filler cap on nice and tight.

I'll double check all them tomorrow when it's stopped raining.

As for the oil cap. Yep nice & tight.

[steve_k]

Well I've just checked & there's no air leaks,

But I found that the throttle is 5/6mm off its stop (open by about 5-6mm) & the cable is very very tight.

I think it might have gy caught when I replaced the head the other week,

Anyone got a picture of the route it take?

[arrisbmw]

are you sure the icv is the right way around. don,t ask how i know that. dupppp

[arrisbmw]

TPS, blue temp sensor, AFM?

TPS is clean and dry, AFM is as new (refurbed) as for the blue temp sensor is there a guide on how to check it?

yes tyhere is by Brian more. best place to check from is the ecu. lives beneath streering wheel. but i doubt its that idle too high

[steve_k]

are you sure the icv is the right way around. don,t ask how i know that. dupppp

I thought that at first but yep it's the correct way round (arrow ➡ pointing to the engine)

I get the feeling the throttle cable is snagged somewhere & holding the throttle open a bit (it's off the stop by about 5-6mm).

[Steve]

TPS, blue temp sensor, AFM?

TPS is clean and dry, AFM is as new (refurbed) as for the blue temp sensor is there a guide on how to check it?

https://www.e30zone.net/e30wiki/index.p ... emp_Sensor

[steve_k]

TPS, blue temp sensor, AFM?

TPS is clean and dry, AFM is as new (refurbed) as for the blue temp sensor is there a guide on how to check it?

https://www.e30zone.net/e30wiki/index.p ... emp_Sensor

nice one cheers steve.

right, been & checked the throttle cable & it's not snagged anywhere in the engine bay,
will be scratching my head all night now.

[arrisbmw]

block the air into the icv then rec0nnect pipe . somehow. if your idle drops you know it an issue with the icv.
i suppose you could remove the pipe to the icv that comes from the rubber boot ( supply air ) tape that up. block the end of the icv thats is exposed.
see what happens , if you still got 3k idle air must be getting sucked in smewhere on the inlet side.

[arrisbmw]

is the butterfly in the throttlr body shut, sprang close when in idle. ?
all air should go through icv. at idle , sorry you probably already know thats.

[steve_k]

is the butterfly in the throttlr body shut, sprang close when in idle. ?
all air should go through icv. at idle , sorry you probably already know thats.

i checked last night & the throttle is open by about 5-6mm but the cable is taught & i thought it was caught somewhere in the engine bay rounf the back of the head, checked there & it's not,

will have a look today to see if it's snagged anywhere around the pedal area, hopefully it's something simple.

[paultv]

Has the tiny locating pin rotated out of it's socket by 90 degrees by any chance - its part of the throttle cable and sits in a nylon groove, hard to see as its under the support flange - on top of the inlet manifold

just a thought

Paul

[steve_k]

Has the tiny locating pin rotated out of it's socket by 90 degrees by any chance - its part of the throttle cable and sits in a nylon groove, hard to see as its under the support flange - on top of the inlet manifold

just a thought

Paul

hi paul, got a pic? i'll have a look when i go out.

[paultv]

here ya go:

slug on cable.jpg

retainer.jpg

and if the slug doesn't sit in its socket correctly, it holds the throttle open too much -

Paul

[steve_k]

here ya go:slug on cable.jpgretainer.jpg

and if the slug doesn't sit in its socket correctly, it holds the throttle open too much -

Paul

a massive thanks for that paul, i gt the feeling it may have "fallen out" when i removed that bracket when i swapped the inlet manifold for the extruded honed one,

soon as this rain eases off i'll go have a look, lets hope its that.

[steve_k]

right been & had a look (in between dodging showers) & that "slug" is still in place.

but, when i put the cable back in place i put it in the lower of the two holes for the cable (it was originally in the upper one) & the throttle shut & rested on the stop, adjusted it to take in the slack & it now works fine.

i will admit it was not me who replaced the cable it was done for me by someone else while i was laid up with a chronic bad back so it looks like they put it in the wrong slot.

all that hassle & worry & it was something simple all along.

thanks for all the help & advise folks.

[steve_k]

before i forget, paul it was that bottom picture you posted that made me think to check the bracket the cable goes into.

[paultv]

no worries, at least you got it sorted!

Paul

[arrisbmw]

here ya go:slug on cable.jpgretainer.jpg

and if the slug doesn't sit in its socket correctly, it holds the throttle open too much -

Paul

how did you manage to get the image on here.
step guide be good please .
thanks Paul , glad you got revving sorted.

[arrisbmw]

here ya go:slug on cable.jpgretainer.jpg

and if the slug doesn't sit in its socket correctly, it holds the throttle open too much -
[/img]
Paul

how did you manage to get the image on here.
step guide be good please .
thanks Paul , glad you got revving sorted.