27 replies to this topic

[fattail95]

Hi there guys,

Still got this problem where there is a lumpy, rich idle. Also, when settling back to idle after a load has been applied it wants to stall, then catches the revs and idles properly again, however still very lumpy and rough. Do all these symptoms point to the idle air control valve?

Here is a vid of it running:



Any ideas?

[fattail95]

Bump, anyone?

[dennismini93]

i have this but on my carb, i thought it might be a weak spark as my battery doesnt really work and it only really runs off the alternator but its only a gess, im not sure at all

[fattail95]

Does anyone have any ideas on this? This issue is driving me bloody insane

[RawlinsGTR]

Had exactly the same problem on my MPi.

I was told quite a few random things to be honest. I never found the root of the problem, mainly because I never tried anything, and also because the cars now sitting in the garage all bent!

Andy at MLM told me the issue would probably be sorted with an ECU reflash, but I had other problems too that led to him thinking that.

Someone else said it might be a stepper motor issue. Which means you could be right!

I'd be very interested to find out the cure to the problem.

Hopefully someone will reply on here, but it might be worth giving a specialist a call and asking for advice, if no one does?

Just a suggestion

Please post your findings back here, if you get any

Simon.

Edited by Dog., 15 December 2012 - 09:54 PM.

[RawlinsGTR]

In reply to your status, if you have a look at this:

http://www.minisport..._MDQ100040.html

That picture shows what it looks like. Looking at that, it seems like it'd be pretty easy to remove. :)

[fattail95]

Really want to get this sorted, been reading up on loads of threads, and the issue started after using RedX to decoke it. I reckon the IACV housing and IACV is coked in soot and starving it of air at idle, which would explain the rich running at idle! Hopefully it is this, otherwise I'm just going to sit down and weep.

[RawlinsGTR]

Nice one.

Let me know how it goes please!

Simon

[fattail95]

Still if anyone has any advice on this let me know!

[fattail95]

Bump

[silver_toes]

I had the same problem on my 1997 mpi. When i took the iacv out it was completely covered in black muck. Quick clean with carb cleaner and she seems to be running much better.

You'll need to take the air box off to get to the iacv (if you've still got the standard one fitted). Definitely try cleaning the iacv first before spending money on new parts.

[charie t]

What did diagnostics reveal?

[fattail95]

What did diagnostics reveal?

Had to go pick up a family friend from the airport today so not had a chance, but will let you know ASAP and take some pics too

[Ruckus]

i have the same problem.

• I was told it was a simple air leak, find that and it would be sorted... there was no air leak.
• I was told it was due to a warped Throttle body, and replacing it with an alloy one would sort it... it didn't.
• I was told it was due to my very high spec AGM battery always pulling charging from the Alt, and using a 'normal' battery would sort it .... it didn't
• I was told it was due to bad grounds in the engine bay, and sorting them and adding extra ground points would sort it... it didn't
• I was also told that a ECU re flash would sort it... it didn't.
• I was told that it had to be something electrical and a very thorough 4 hour diagnostic would find the problem... it didn't
• I was then told AS FACT that the problem was the engine had low Vacuum but it was not the head and it had to be pulled stripped down to find the problem, I went one better and replaced the engine and gearbox with a rebuilt recon'ed 1293 new cam etc... and after many hours of work and bleeding knuckles did it sort the problem... IT DID NOT.

I've come to the realization that unfortunately many experts in the mini scene that are great engineers when it comes to the original A series and points/carbs etc, know very little about MPi's.

I'm not going to directly name the company who told me most of this, but they have already been mentioned in this thread...

If you think about it why would they put much effort in to learning about them, 40 years of Carbs and points and 4 years of MPi's.
Most of the cars they work on are 'classic' and a basic gears, oil and a hammer approach will work. Where as MPi's need diagnostic equipment, electronic engineering and even some computer skills to fully understand.

My next step is to park next to a friends perfectly working MPi and start swapping parts and sensors.
All the diag's I've had done report no problems (so i'm told...) with any sensors but low vacuum is causing the ECU to retard and scatter the timing, when it should be advancing it...

http://www.theminifo...s/page__st__105
http://www.theminifo...01-poor-idling/

Edited by Ruckus, 18 December 2012 - 10:37 AM.

[charie t]

i have the same problem.
I was told........

You were asked about, nobody has told you it was definately
The "4 hour diagnostics" should have revealed a problem if it was carried out by a trained technician, The more details you can give the easier it makes. If you could give the readings from live data, it could point to the area you want to look at.
Unfortunately people assume that a computer will simply say, bingo thats your faulty part, most of the time it will, but in some cases it needs somebody to take the readings, test and understand what is going on.
Guess work costs and does not always solve the issues.