Misfires again

[Wobba]

Same as before. Electrical in nature, can hear the relay in the engine bay clicking when it misses. It has been like this for some time, on and off. I've replaced:

Coil pack (Megane one)
Spark plugs (several times)
Crank sensor (twice)
TPS (special one for ITB's/Jenveys)
Rewired crank sensor
All relays replaced
ECU sent to Emerald ECU's for testing (was some scrambling to code due to some kind of electrical interference)
Swapped to Walbro performance fuel pump
Rewired pins for power and crank sensor on ECU harness
Rewired main wiring for ECU/Ignition/Fuel pump relays

I've had a leaky camcover for ages, it is NOT the seal or the head itself as both been replaced and it still leaks into spark plug well no.2 This itself fouls the spark plug and causes a loss of power and generally rough engine revs. I had a theory the spark from coils could have been discharging through the body of the car causing damage somewhere as the oil levels in the spark well got very high.

It could be something shorting out, or an old part of the wiring loom I have not checked I guess.

I have no problem starting the car and it does not happen when I just start the car from cold, it only seems to be when hot usually.

I cleaned the oil out the other week and last night and replaced plugs last night again but although it felt nicer to drive, the misfire started again on the way to work.

Might take it to Emerald themselves and let them play with it, this is doing my nut in! Always happens when I least need it to happen as well...

[Wobba]

I know it must be something simple that I have missed, damn frustrating though when I currently rely on car for transport!

[Wobba]

Could a dodgy immobiliser cause it?

[Wobba]

Started car up and let it run for a bit at work before I went home. I grabbed a handful of wiring loom and shook it about. There was a distinctive change in revs sometimes when moving some of the cables and I thought I got the relay to click once or twice when wobbling it about. I thought it might be injectors but the misfire persisted even after unplugging each of the injector power supplies.

I am SURE this is a wiring loom issue, could be shorting out on another wire or causing interference to the ECU power supply somehow, or crank sensor.

I'm going to take it off and take it apart and check it completely. I'll rewire it some nice colours too :D

Off to see another car on Saturday over in Bristol, 0217 might have overheard this and has started misbehaving in protest! I will fix the little ****er for good this time!!!

[stevie_b]

Off to see another car on Saturday over in Bristol

What's that then? Spill the beans

[Wobba]

[16v_paddy]

There's a wire on the loom somewhere that I know can cause problems if it goes anywhere near the crank sensor wire, ****ed if I can remember which 1 it is though

[Wobba]

Might be something like that.

[icenutter]

Hopefully you've found the solution to your problems!

[Wobba]

Well, I ripped the alternator out and all the ECU loom and pulled it apart. No clear issues but I moved the crank sensor cable away from all the others. Gave up for a bit as it was raining hard. All back together, new alternator on, which blew up the first time, was repaired, refitted and showed regulator issue. Electrician said the regulator wires were wrong way round so I swapped em and rewired it. Went for a start and battery warning light is on, meaning no feed to battery...this will be the 5th time I've swapped that new alternator out.

Up at 7 am to go see another car for sale in Bristol. If it keeps misfiring after this and I spend ages ****ing about with the alternator again...and I buy this car tomorrow...I might break or sell the Clio. I really mean it this time, I am tired of stupid problems that are so hard to find and working in the rain/cold/snow/dark. Otherwise I will put it in a garage and strip it for trackdays and let someone fix the electrical issue for me.