3000rpm mixture = good, above this sudden drop off to rich

[Stigmundfreud]

any suggestions? The mixture was running at 14.1 up to 3000rpm (which is a vast improvement over the last time it was checked at 10.1 flat through the range) but under load above 3k rpm it dives vertically to 10.

The car has capa headers and miltex system. I'm suspecting the O2 sensors but would like to hear any other potential suggestions?

[well_fans]

hmm interesting - especially as I'm looking at putting a set of Capa headers onto my Milltek. What headers did you fit 4-1 long tube or try-y? Any problems getting them matched to the Milltek exhaust - did you have to get a custom section made up?

[ringram]

Have you had it tuned?
What are you measuring with?
If it runs ok to around 3000rpm, then you may find your MAF needs calibrating as it usually takes over around 4000rpm the fueling tasks.
If its ok up to 3000rpm that suggests the O2's are working ok.

[Stigmundfreud]

well_fans: I had the 4-1 set up, the cats were removed and shortened and done really well, from looking at it I can only say that any long headers will need this unless using cat bypass pipes but even then the cats wouldnt fit back on without mods - it was a painless task and all done whilst the headers were being fitted.

ringram: Suspect a tune up could be in order and it is being aranged, it wsa being hoped in the mean time before it is done that the previous map would have taken care of things until a proper remap is done. My email last night should explain things better

[Stigmundfreud]

ring, just a quick question

the sudden drop to rich isnt going to damage the engine whilst waiting for the tune is it? I mean prior to this it was running 10.1 accross the range so at least its running good until the maf kicks in to action

with it running rich its not about to self detnonte is it?!?

[ringram]

Nope, lean is the bad side. You will be well down on power an suck loads of fuel though.
Too rich can wash the cylinder walls of oil and cause increased wear. But you will probably be ok. Just keep off the bottom of the accelerator until its sorted is the best bet.

[mackie1]

It shouldn't, it's running too lean that causes engines to blow.

[Stigmundfreud]

that was what my understanding was so thanks!