Engine fault light comes on during wot

[dave364634]

Basically I gave it wot for the first time in a while, and the MIL light came flashed until I lifted off.

When giving it wot again during the trip it was back to normal. Performance is fine, and its an 01 986 S.


What was the likely cause of the light, carbon build up?


Ta.

 

[Melv]

Wot?

 

[Motorhead]

Melv - WOT = Wide Open Throttle

Dave - Do you mean the CEL? Could be a lambda (O2) sensor fault.

I think that if the CEL is flashing, you shouldn't really drive the car like that but a solid light is OK (?). I'd get a diagnostic check ASAP to see what fault codes have been registered.

Jeff

 

[Boxstercol]

Coil pack breaking down under load? Common in cold weather.

 

[dave364634]

I think it was where C is.

http://www.renntech.org/forums/uploads/monthly_11_2012/post-85427-0-43531900-1353524568.jpg

It definitely had 'check' on it.

It was strange that it didn't do it 30 seconds later though.

 

[Motorhead]

You need to check your 986 Driver's Manual to identify the warning light Dave.

But if it definitely read 'Check', I suspect that it was the Check Engine (Emission Control) warning light (Q on your diagram).

If the engine wasn't misfiring, the coil packs/plugs are probably OK (although still worth checking out). Since the problem only occured once, and then only after you'd given it a bit of stick for the first time in a while, it's probable that you "shocked" the system and the lambda sensors over-reacted to the clear-out.

As I said, if you've any concerns it's best to get a PIWIS/Durametric diagnostic check which will read any fault codes logged.

Jeff

 

[dave364634]

No codes found. [&:]

 

[spyderman]

My road 986 never shows its CEL after full throttle (track days) unless I've done Rockingham and suffered oil surge - when its also accompanied by smoke signals to the Arapaho, Sioux and Comanche tribes simultaneously.

By contrast my race 986's CEL is on almost constantly! We don't know what causes it but if we clear it, it just comes on again.

I'm with Jeff that its lambda sensor related.

 

[Richard_Hamilton]

"C" is the PSM light, so it could be the MAF sensor. If an implausible signal is sent from the DME to the PSM controller, the PSM light will flash, and this could be happening at WOT if the MAF is under-reading. The Check Engine Light will not come on, because it isn't programmed to do so on UK cars for a MAF error.