this is completely stumping me now, i thought the engine had given the ghost, but after a compression check and timing check it all seems fine, so thought id get it ready for MOT so took the lambda off just to give it a clean, oil change etc on saturday, i did all this so had all the HT leads off checked the plugs etc gave everything a once over and all seemed fine, put it all back together, went out to get some petrol and it was running amazingly, smooth no stammering under acceleration smooth boost no lumpyness it was great, then about 15 minutes in the cat warning light came and then almost immediatly the car started running like crap again, lumpy hesitant almost as if missing, got home checked for error codes and none, in addition to this the ecu fuse was pulled, so somehow from doing the above it tempararily cured the problem i have in my head what i think the cause could be but can any body hazard a guess to see if its what im thinking.as i cant keep justifying throwing money to change stuff thats not damaged.

any ideas whould be appreciated

Well if the cat warning light came on are you sure the cat ain't knackerd?

Cat overheat normally indicates retarded ignition timing or weak mixture.

When checking igntion timing, did you link E1 & TE1 and verify the engine light was flashing ?

_________________
If at first you don't suck seed, try drier grain.

i checked it correctly timing was bang on which is why this is stumping me, like i said before ive changed the leads, plugs, dizzy, rotor arm, coil pack, im wondering now if it could be the lambda but dont know enough about them to determine what happens when they are shot and dont want to carry on spending money replacing things that are not the cause, as for the cat being knackered it started coming last year (sounds bad but it doesnt get driven anymore) so thought it was just a gremlin as it was fine when i laid it up for winter and then came on the first time i drove it afterwards so it now comes on intermitantly, i could drive along normal road speed get over 2000rpm and it comes on drop below 1900 it goes off, then other times when its off i can give some beans and it doesnt come on for a while so it doesnt feel consistant with when it comes on

could the lambda be the issue, how did you clean it?

Honestly, I could be talking crap however

_________________
FN2 Civic Type R w/Mugen Parts
Toyota Celica GT4 ST205
Toyota Celica GT4 ST185

cleaned it by siticking it in a lemon but ive been doing that for the past few years (it works really well too) and nothing untoward after, does any body know or have tested the lambda on the car? what should happen, something i did notice when i unplugged the lambda no light came on so does the ecu even know when it is not working?

Intermittant knock sensor fault maybe. they usually cause a check engine error at about 2000rpm? but im sure it stores the code if it does.

thats whats blagging me, the lack of error codes

Does it trigger in neutral?

Really does sound like knock sensor fault ecu ignores it below 2000rpm and only registers fault over 2000rpm had it happen to mine. You could unplug it ( fiddly ) and see if it stores a code if not i bet its that...

Knock sensor fault is flagged when engine goes above 3000RPM and sees nothing from the sensor. This brings on the engine light, retards ignotion and cuts boost (if ECU controlled). The light remains on (and it's effect) until ignition is switched off.
Switching ignition off & on will turn off engine light and remove the effect, but the code is stored and will show on fault code check.

The other thing that could cause these symptoms is too much signal from the sensor fooling the ECU into thinking the engine is detting and thus pulling timing. I don't see how the sensor can fail oversensitive, but since the sensor is referenced to engine ground it could be a poor earth connection (ECU earths under inlet manifold) or wiring shorting to comething else.

_________________
If at first you don't suck seed, try drier grain.

this only happens under load, revving whilst in neutral is as normal

Just to check - you engine warning light is coming on when you switch the ignition on? Check that the bulb has not been removed.

_________________
GT4DC Events Co-ordinator
1996 ST205 UK

yep engine light comes on as normal when starting goes off as normal