P75 vs P28 diffences?

I got a b18B1 turbo engine in my 95 civic ex. I swapped my p75 out last night and installed the p28 as I will be going ls/vtec soon and can use a higher redline/vtec capabilites.


PROBLEM: as soon as I start running boost around like 3
psi my A/F guage shows me going lean, i reset the ECU and same thing. I put the p75 in and it was fine. tried it again and yup went lean. What would cause this? are the fuel maps that
much different? or does it not go into open loop until vtec? timming different? What would cause this?


Kyle

You have to give the ecu's fuzzy logic a little while to adapt to the way your engine runs. Just go easy on your car for a little while and let it adapt. I don't know what your gonna do about wot since that is a set map. The fuzzy logic only works at part throttle operation. If it wont run properly at wot then your gona need some tuning.

So put it in a drive normal for a bit? I had it in for about 30 min but it kept going lean under boost... sisnt want to keep taking the chance so I put the p75 back in before something went. p75 was fine right away.

The P28 needs to have a knock sensor to operate correctly. Don't know that this is the problem but could have something to do with it.