nitrorocket

Well, you need to get a chip that has rear 02 delete... removing the cats will drastically lower the after car exhaust temp and tell the ecu to add more fuel to raise cat temps. Maybe this is causing the misfires and overboost from an over rich condition. Unless you specified to the chip supplier that you were not using rear 02's already.Not usre if this is your problem, but it sounds like the first step to investigate.

2.7Lturbo

you really do show your ignorance with these cars


the rear o2 does not actively control the fueling loop. and if you wanted to raise the cat temps you would lean the mixture out to up the egts........ really dude 15 years of race car building?



slobodan, please do not follow this line of thought in figuring out whats wrong with your car. there are so many things fundamentally wrong with this post

2.7Lturbo

OP

you have a ko4 on a ko3 chip, you have not told us the boost levels you ar running or what upgraded fueling you have. you can not simply bolt on ko4s and call it a day. you need to make some tweaks to get it to run. and running a ko4 at the bost levels your chipped ko3 was at, without increase fueling capacity (think injectors/fuel pump) you can cause some serious issues.

also have you checked your spark plugs? i would be there is damage to the electrodes

my advice is check spark plugs (report back to us with pics) and put a boost gauge on the car and go for a drive, that way you can tell us what the boost level is, and what its spiking to

slobodan

Thanks...It was two different banks, so it should not be the sensors (check engine light should be on). Do you have any other suggestions how to fix it or where to bring it to be fix. (re- program)
Thanks

slobodan

I will do that. Give me a couple days (busy with some other things) and will put boost gauge and will check for fuel pump/lines/injectors. Car drive nice if is not push hard.
Thank you