Supercharger/idle/fuelling issues
Turbo Mini Forums

Hi guys, hope this is in the right place.

Ok this is my first real plea for help since signing up, I have read through a lot of the posts on spark plugs and have read a recent thread regarding idle problems but haven’t been able to find any solutions to my problem.

I will try to be as detailed as possible but I’m not a great mechanic, so you will have to try to forgive my lack of knowledge. I am trying to learn but have only had a mini for a couple of years and only got the supercharger at the end of summer and that was a bit of a step into the dark.

The car was initially an SPI Cooper; I dropped it off at Vmax for the supercharger conversion, and rebuilt gearbox etc. Stuart advised that it would also be beneficial to use the MPI throttle body and single injector to ensure enough fuel was available. I have the Emerald mappable ECU and wideband controller.

The problem started a couple of days after I collected the car when the manifold gasket blew. I eventually managed to fix this with some help but the car ran rough and I could not get it to idle. I eventually realised that the plugs had fouled, changed them and managed to get it running again. However within a day the idle had gone again.

I assumed that it must be running rich at idle and fouling the plugs so hooked the ECU up to the laptop to assess the values. Using BPR6ES plugs as I was unable to get 7’s I managed to sort out the idle fuelling, let it get up to temp and set at around 1000rpm as Stuart suggested. Allowed to idle for a while and the plugs were clean.

The car than worked OK for a day or so before it started hunting at idle and the plugs fouled again.

This has been on and off for a while and I have been speaking to Stuart about possible causes and tried various plugs/possible solutions etc.

He talked me through re-setting the lambda sensor in case this had been affected by the exhaust problems and so might be throwing the fuelling out but this had no real effect.

This weekend I used a clean set of plugs, set up the idle and drove for an hour or 2 with no problems. Went to start the car the following day ant it wouldn’t idle, was misfiring and stalled. Looked at the plugs and they were black again!

When I cleaned them up and set the idle all was fine. Checked plugs after 15 mins and they were clean. Went to start it and it just stalled unless I held it on throttle and increased idle speed using the screw, every time I set the screw and turned off then on it just stalled.

I have now tried;

3 different types of plug
Changed leads etc.
Leaned off fuelling at idle
Reset Lambda sensor
Checked for air leaks

I haven’t been able to get the car back down to Vmax as it is a considerable distance and my own fault for not doing things closer to home. However Stuart was highly recommended and I have no problem with how he has dealt with things. He has been really helpful where possible and has always come back to me but it sometimes takes time as I understand he is busy and not always available when I am.

Just wondered if anyone had any ideas as to anything else I could try before thinking about getting it back down to Surrey for him to have a look at!

And apologies for the long post!

Thanks

Chris

What system are you using for idle air control?

Sounds like you are getting the extra fuel at cold start, but not the extra air required.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Exhaust leak? Lambda sensor knacked?
Regards
Dave

As far as I know it uses an IACV from the MPI?

Can you do a datalog and post it here?
Regards
Dave

I'm not sure how!? I got the software with the wideband controller but could not get it to connect to the laptop when I hooked it up.

I will try to have a read of the manual tonight.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Id refrain from messing around with too many settings.

I know stuart has spend many hours refining his maps and then spends alot of time tuning in the cars to make sure they are right

Buy fiddling around with it too much you run the risk of putting alot of variables in to the car which wont help it run at all

If your having idle problems then it could well be another air leak, a hose or connector incorrect, or somehow your managed to adjust the map, maybe see if stuart can email you a base map to try

However it may be for the best just to get it down there really

Edited by Nic on 4th Jan, 2008.

Hi,
As it appears to run fine when warm, I'd suggest looking at warm up and cranking fueling setups.
Most ECUs have a table to set the extra enrichment against temperature for the warm up phase.
This maybe where your problem lies?
Cheers,
Gavin :)

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