well i just bought a 98 cobra w/ ati & intercooler 42# injectors and an msd. it is detonating at wot from like 6000 rpm and up but at 3/4 throttle @7000rpm no detonation. i know it has a dyno tuned chip but the 42#'s were installed after the custom tune. other than that the car idles great, and runs fine. i beleave it has the stock fuel pump, is this my prob or should i get the chip redone? for now i will use the msd to back timing out but i want the fuel to be there.
yikes! detonation
- Thread starter kmoore281
- Start date
What is your fuel pressure at 6000 +rpm?? Sounds like at minimum you need to get an upgraded fuel pump. Also, what are the A/F ratios at 6000 and 7000 rpm? If the 42# injectors were installed after your tuning, they may not be opening up when you really need them to. Get that puppy to wide-band dyno. I wouldn't drive it hard until you find out for sure...cracked pistons are an expensive repair!
fuel pressure under boost is 30-35 psi! now thats scary! so i am changing the fuel filter first and swaping out the ati pro pump for an aeromotive and swapping out the stock intank pump for a 170 lph pump from frp. i found out that the chip was redone for the 42# injectors but am going to get a new chip done. im looking at alternative automotive to do the chip, they custom tune chips for reliability rather than over all horsepower numbers, and i have been very nice to the car until the pre ignition gets resolved. the good thing about lots of power is even @ half throttle up to 5500 rpm is fun!
by the way that vette sounds and looks like a bad mutha!
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