NotoriousREV

OK, car spec first: MY93 WRX, full Scoobysport decat, HKS induction kit, ScoobyECU by Scott.T, Turbosmart boost controller, Bosch coils with Magnecor leads, NGK 7B plugs, otherwise all is standard.

For a long time I've had a problem with the car misfiring in the wet, more specifically running on 3 when on boost, which always clears up within a few hours of the weather drying up. I've always put this down to the mounting location of one of the Bosch coils and the fact that my bonnet vents don't have the backing plates.

Last weekend, after putting up with this for a year, the misfire got really bad so I moved the coil I suspected was giving me grief (i.e. the one that when I disconnected the plug lead didn't make it run rougher) which initially cured the problem.

This week, however, the car's run like a bag of crap, it drops onto 3 cylinders at full throttle over 4000rpm in any gear or bucks and misses violently (not fuel cut as the boost isn't getting high enough for that, but a similar feeling) and while it's missing the rev counter drops to zero and the AFR meter goes nuts.

So, by process of elimination and enough knowledge to be dangerous, I'm guessing it's a dodgy coil, but I'm also suspicious of the fuel pump as I'd noticed that was a bit noisy last week.

The reason I suspect the fuel pump is that the last couple of days (when it's been dry) it's stopped dropping onto 3 and started bucking and missing more.

What I could do with knowing is: how can I test the coils to decide if they're working OK at high revs/boost? How can I test if the fuel pump is OK?

Any other suggestions welcomed.

sparkywrx2

you could check the fuel pressure on full boost or check fuel ratios using a wideband lambda if you know anyone with one.

My 94 wrx coil packs couldnt cope when I turned the boost up above 1 bar, which gave bad missfire. had to buy new ones which cost about 200 quid from dealer.

why dont you try lowering the boost and see what happens

oh, I dont think the fuel pump could cause this, I think it would just start to run lean if the fuel pump is struggling.

Buzzer

C'mon mate even you know that must be a faulty rotor arm / distributer cap

NotoriousREV

Impossible, I've sprayed it with WD40 and everything!

vulnax999

iTrader: (7)

Plugs, plug gap, plug leads, poor earth,

Have you got a top mounted coil and plug leads to plugs or coil pack per plug?? May be the individual coil packs shorting out when wet if cracked? I have some spares you can try if you want, if that sort.

Reset ECU and see if helps.

Let us know by thursday!

NotoriousREV

Neil, cheers for the offer! I don't suppose you have a full set of coil packs I could borrow, have you?

I'm off to France tomorrow, so I'll sort it out when I get back, currently running 6psi and it doesn't misfire

I think it's going to be new plugs (current set have done 25,000) and new coils (probably go back to using coil packs rather than the Bosch coils).

ZIPPY

I have a can of petrol at the ready if all else fails, you could always give it the send off it deserves.

NotoriousREV

I'll give you the nod mate...