Here's the problem:- I set off for work last Friday with the car running perfectly, got about 200 yds and it dropped onto 1 or 2 cylinders. I limped back home and have tried the following:-

Swapped ECU
Swapped coil
Swapped ignition amplifier
Checked plugs - no 4 was dry, nos 1, 2 & 3 were wet to a greater or lesser extent
Turned over the engine with no 1 plug out and resting on head - fat blue spark.
Cleaned plugs and dried them off with a blowlamp

So, it's getting fuel (I can hear the fuel pump running, the plugs are wet, I can smell unburnt fuel coming out of the exhaust). There's definitely a spark as far as I can tell.

It's still running the original (off the donor) dizzy cap and rotor arm and I can't get spares on a Saturday so they've not been swapped. Can either of these fail in such a sudden manner? Both look OK in that they're not cracked or falling apart, but I don't know what else to check for.

So, what's the problem? I don't have the facilities for a compression test and it seems odd that the failure was so instantaneous, so for the time being I'm discounting the possibility of head gasket / rings / piston failure (rightly or wrongly).

Anyone got any ideas?

Ta,

Eddy

[Edited on 22-7-2006 by eddymcclements]

Are all 4 plugs sparking or have you just checked number 1?

Have you got a fuel filter? What fuel system are you using?

DIY Si - I know number 4 is OK because a. the plug is dry and b. the exhaust header gets hot. I was time-limited on my investigations, so I just checked one of the wet plugs to see if it was sparking at all, and it was.

Peteff - I have a nylon gauze pre-filter, Bosch injection pump, EFI post-pump filter, solid lines to the injector rail, stock Toyota FPR with vacuum hose and solid lines leading back to the tank. I don't suspect the fuel system at the moment because the plugs are getting wet, there unburnt fuel at the exhaust and I can hear the fuel pump running.

To be honest I think the most likely cause is a faulty EFI sensor, a fractured wire, a problem with the trigger in the dizzy or the cap or the rotor arm. Or something worse. When the motor dropped from running cleanly to running badly I'd only gone a short distance and had probably only just shifted into 3rd.

Cheers,

Eddy