My fuel is tuned to run 11.6-11.8 WOT on 98oct and I had the occasional 1-2 knock counts. I use evoscan and log regularly. My multipiers are LOW 18 MID 20 HIGH 20.

Last week I went away on work for 1 week. When i got back i went for a drive and had some really high knock counts (4-9) mainly around 5500rpm (280-290 load) and up and also quite a bit after releasing the throttle with load around 120. the car feels great and pulls hard so im stumped. i logged again and found that my afr's are around 12-12.2 WOT. now nothing much has changed, weather is similar also.

Does this sound like an injector thats dying and causing the leanness?? or something else? i have stock injectors and IDC is between 92-102% at WOT. the smoothness of IDC and IPW in evoscan is not as smooth as it used to be. im not boosting till i sort this but i dont want to damage my engine, HELP!!

EDIT: One more thing. Knock voltage doesnt reflect knock sum counts are they usually do, they are sometimes under 1.0v even

 

change your fuel filter would be the first port of call.also how long has your fuel pump been in? 12AFRs are fine i wouldnt worry about that too much.a knock sum of 4-9 is not that high a degree or 2 ignition will bring that down.you must be running around 1.8 bar boost for loads that high.

 

i installed a new walbro 255 about 2-3 months ago with the new filter on the end that came with the kit...is there another fuel filter?

i'll try adding a bit (0.2) more fuel and i've already taken 1* of timing out where im logging the knock which didnt appear to do anything. I always log knock voltage and it is relatively low now compared to when was tuning a few months ago and registering knock.

one of my coolant hoses ruptured a couple of days ago and i had all the coolant leak, lucky i was near home and engine was still coolish. initially i thought it may have something to do with engine temps being higher but dont think that has anything to do with it now since i fix it it still doing it. its just wierd that this started happening since i got back from a week away.

 

SOLVED. It was the O2 sensor, it was on its way out.