engine cut out at 3500rpm

[shadrack]

I posted this on the facebook other day, and got one reply saying AFM, i was thinking poss fuel filter (cars been stood a while)

So just bought car and giving it the once over when i got back see what i need to do, if i accelerate hard at around 3500-4000 rpm the car cuts out for a split second (hard eough to jerk you in your seat) then carries on past it to 6500rpm however intermitntly does the same at 6000rpm, engine seems sweet its quiet not tapping etc, drives perfect under this rpm and over it also starts perfect, any ideas? ta

[Brianmoooore]

A clue or two as to which engine you have would be useful!

[shadrack]

sorry its a 1988 325i m20

[shadrack]

Also noticed that if i plug this back in (is it idle control valve?) it kangaroos and cuts out at 1200 rpm

[shadrack]

also might be slightly higher rpm perhaps 4500

[jmc330i]

Also noticed that if i plug this back in (is it idle control valve?) it kangaroos and cuts out at 1200 rpm

You normally run it unplugged?

[shadrack]

ive just bought it and it was unplugged, but with it unplugged it runs fine apart from the above split second loss of power, with it plugged in its un drivable, kangarooing and going to stall, im going to clean it out i think

[shadrack]

yeh i know ive got work only had it 2 days and its doing my head in, ive printed the wiki pages off so when i get time, ill go through the list, its just strange how 90% of time its fine, cheers

its just had a timing belt according to ticker under bonnet, wonder if its out

[jmc330i]

its just strange how 90% of time its fine

If it runs better with the ICV unplugged, it's not fine.

[Brianmoooore]

Chances are that this engine developed a simple fault - one that could have been easily sorted by someone who knew what they were doing. Unfortunately, I expect some clueless f**kwit has been let loose on it, and has proceeded to 'tweak' every factory set adjustment they could find - ones that interact with each other, and only have one correct position, set up with specialist equipment. After messing everything up, they discovered it would 'sort of' run if the ICV was disconnected, and then proceeded to unload the car on some unsuspecting punter, which is where the OP comes in.
If the above is anything like the truth, you're going to have to work through everything, bit by bit.

[shadrack]

haha ^ this is what im suspecting problem is the weather, ive a quiet week at work this week and its not stopped bloody raining

[shadrack]

Right so done a little work on it, tps cleaned and tested with a mutlimeter and all working, definatly idles far better with icv plugged in however with it plugged in it wont rev past 2000rpm, without it it still cuts out at high revs. ICV cleaned out also.

TPS- i ake it i should hear the tiny click when puting a tiny bit of throttle then the other switch makes at around 3/4 throttle as per wiki

[Brianmoooore]

Your interpretation of the TPS is correct. The click must occur as soon as possible after the throttle moves off of its stop, and its action should be confirmed with a meter - a click is good, but doesn't mean it's definitely working.
I can think of no possible way that plugging in the ICV can stop the engine revving. Once the throttle is off its stop, the ICV is irrelevant - it's just a small auxiliary throttle working in parallel with the main one.

[shadrack]

Your interpretation of the TPS is correct. The click must occur as soon as possible after the throttle moves off of its stop, and its action should be confirmed with a meter - a click is good, but doesn't mean it's definitely working.
I can think of no possible way that plugging in the ICV can stop the engine revving. Once the throttle is off its stop, the ICV is irrelevant - it's just a small auxiliary throttle working in parallel with the main one.

confirmed it with a meter out the car, the previous owner replied to my message asking why the icv was disconected saying the icv was mapped out, is this even possible could all my woes be down to a crap re map? i cant see why the icv would stop it reving over 2k but it does i have a video of it

[pianist]

It might be a good idea to get a chip from a guy around here he seems to be doing a good job I just can't remember his name atm but sure someone will be able to tell you

[pianist]

It keeps on bugging me, why would you map out the ICV and by doing so you would probably need to adjust fuel ratio wich might be the cause of your probs

[shadrack]

is a standard ecu plug and play with no coding if i could get hold of one? the previous owner said that it might not be true!

[pianist]

Found him: http://www.e30zone.net/modules.php?name ... highlight=

If you pm him he will be able to tell you way more about ECU's than I can

[Brianmoooore]

You need to beg, borrow or buy an unmodified 325i ECU, preferably a 173, and try that on the engine.

[shadrack]

You need to beg, borrow or buy an unmodified 325i ECU, preferably a 173, and try that on the engine.

i think this is the best place to start if its been messed with, its doing my head in now lol

[Speedtouch]

It keeps on bugging me, why would you map out the ICV and by doing so you would probably need to adjust fuel ratio wich might be the cause of your probs

I know some standalone systems, e.g., Megasquirt, sometimes do away with the ICV completely, but they can be a pig to drive from a cold start, and almost undriveable until the engine warms up.

Another possibility, if you have a later 0 261 200 380 ECU, is that the diodes in the idle control circuit have blown - quite a common fault. In which case, as Brian said, you are best off replacing with a known good 0 261 200 173 ECU.

[shadrack]

ive not given up and think its something daft as with the icv unplugged it idles fine and drives perfect apart from the glitch at high revs, with icv plugged in it just wont rev, thing is it needs alot of other work to bring it back but im starting with the boring bits first such as the running,

[shadrack]

heres a vid, this is icv pluged in pedel flat down as if to rev it to redline

[Cypriotgeeza]

I had this same problem after I replaced the head-gasket on my M30

I tried EVERYTHING to fix it..changed everything I could think of..Nothing worked..

Then someone on here reminded me that the Plugs on the ICV and TPS were exactly the same and maybe I Mixed them up..

He was right

Worth a look otherwise it sounds like a 2nd hand Ecu would to the job there is still plenty about!

Where abouts are you based?

[Brianmoooore]

Then someone on here reminded me that the Plugs on the ICV and TPS were exactly the same and maybe I Mixed them up..

It would explain why plugging in the 'ICV' stops it revving.
Pull back the rubber boot on one of the plugs and tell us the wire colours. DON'T just jump in and swap them over.

[shadrack]

ok currently the plug going to icv is orange in middle, brown and black and brown and blue, if someone can check against there m20, thanks

[shadrack]

I had this same problem after I replaced the head-gasket on my M30

I tried EVERYTHING to fix it..changed everything I could think of..Nothing worked..

Then someone on here reminded me that the Plugs on the ICV and TPS were exactly the same and maybe I Mixed them up..

He was right

Worth a look otherwise it sounds like a 2nd hand Ecu would to the job there is still plenty about!

Where abouts are you based?

near middlesbrough is where i am, thanks for the advice

[Brianmoooore]

Your orange is actually brown, but that is definitely the TPS plug! Swap 'em over.
I wouldn't have thought it possible to swap them over on a M20 loom, but I stand corrected. Possibly more likely if the loom binding tape is falling off.

[shadrack]

Your orange is actually brown, but that is definitely the TPS plug! Swap 'em over.
I wouldn't have thought it possible to swap them over on a M20 loom, but I stand corrected. Possibly more likely if the loom binding tape is falling off.

hope it cures it, this would explain why its so had to get the icv valve plug to reach (ps ive just bought it like this)
here (also got 2 year old on my knee so struggling to change instantly!
[/img]

[shadrack]

Well f**k me get these men above some beer!!!!! just swapped these plugs started it up and it revved up pefectly!! , not had chance to drive but im asuming now i had a working tps as its plugged in i will of lost my miss at high revs as in the thread!! whats the betting its the reason previous owner sold it!

right now to sort the bodywork which i know alot more about than engines

THANKS

[Cypriotgeeza]

Well f**k me get these men above some beer!!!!! just swapped these plugs started it up and it revved up pefectly!! , not had chance to drive but im asuming now i had a working tps as its plugged in i will of lost my miss at high revs as in the thread!! whats the betting its the reason previous owner sold it!

right now to sort the bodywork which i know alot more about than engines

THANKS

Result!

[shadrack]

well the only way it would drive was unplug icv (which was tps sensor wire) so when i was driving i had no tps so i could asume my high revved miss fire should have gone as well now, but will have to wait till tomoro now as the headlights dont work at min and i will have little one till after dark

[Brianmoooore]

Well f**k me get these men above some beer!!!!!

Biggest thanks must go to Cypriotgeeza, whose intervention has shortened this thread by about two pages!
The layout of items on the M30 engine is different than that on a M20, and it may well be possible to easily mix up the ICV and TPS plugs, but I really did think there was no real possibility of this on a M20. I now know differently.
Biggest problem now is to identify what the previous owner, who seems to spout a considerable amount of bullsh*t, has messed up in his attempts to sort the car out.

[shadrack]

Well f**k me get these men above some beer!!!!!

Biggest thanks must go to Cypriotgeeza, whose intervention has shortened this thread by about two pages!
The layout of items on the M30 engine is different than that on a M20, and it may well be possible to easily mix up the ICV and TPS plugs, but I really did think there was no real possibility of this on a M20. I now know differently.
Biggest problem now is to identify what the previous owner, who seems to spout a considerable amount of bullsh*t, has messed up in his attempts to sort the car out.

This is so true, luckily in my quest ive only managed to change fuel filter and strip, test and clean all intake side components which can only be a good thing.