Rev counter behaviour after misfire.

[JPL]

Ok guys, any ideas.

I got a coil pack from Doug to help diagnose what I thought was an ignition problem. Before I went and started cutting and soldering I thought I'd give it a good blast to replicate the high boost/high gear senario. Got the misfire when boost went over 1.2 bar at WOT in 5th and 6th. Started slowing down again and the rev counter looked like it was stuck at 1200 rpm, but it sounded as if it was idling normally. Rev'd it up and nothing, then it goes to 2800 and stays there, then back to 1200 if I let it idle again. These look to be set readings of some sort to indicate a fault. Is my crank speed sensor duff and could this be causing my misfire? If I switch the ignito off and on it goes back to normal, if it misfires it only reads 1200 or 2800.

Anybody got a clue what this lot means?

Graeme.

[Mihnea]

ECU problem???? can you make sure the ECU isn't covered in water??? this is a serious and recurrent problem on LHD S4/S6s where a drain gets plugged and water drips straight onto the ECU.... defo sounds like an ECU related problem to me...

HTH,

Mihnea

[JPL]

ECU problem???? can you make sure the ECU isn't covered in water??? this is a serious and recurrent problem on LHD S4/S6s where a drain gets plugged and water drips straight onto the ECU.... defo sounds like an ECU related problem to me...

HTH,

Mihnea

Thanks for the advice Mihnea, I'll get the carpet out and check tomorrow.

Cheers,

Graeme.

[JPL]

Couldn't wait, out to the drive and stripped out the ECU. It was dry but the foam under the carpet is soaking, the drains were blocked a few weeks ago and I cleared them but not before some water got into my footwells through the heater blower. I thought I'd got away with it. I've taken the ECU in overnight just in case there is any moisture left on the PCB's.

Help Mihnea, if it keeps doing this i.e. full boost misfire then the rev counter thing are we talking a replacement ECU, has the damage already been done?

I'll continue looking at the ignition side of things just to be sure the misfire isn't causing the rev counter to chuck it.

Graeme.