ok i got a 89 LX sedan that i did a mpfi swap in.

problems are - no power above 4500 rpm and the o2 sensor CEL comes on after only driving a few blocks.

mods are CAI, adj cam gear. other then that its all stock.

known issues other then the above is small exhaust leak at exhaust manifold to downpipe. 1 of the 3 DP studs are broke.

i had a chipped ecu in it and the only time the o2 sensor CEL would come on was when under a heavy stress. like going up a hill driving into the wind. in an attempt to get better mpg i put the stock ecu back in and retimed the engine. the timing is dead in the middle of the 3 notches.

when trying to give it some throttle, once it gets around 4500 rpm it bogs down big time, almost like a reverse vtec. it does go all the way to rev limiter but it sure takes time to get there.

im open to any ideas or suggestions. things to check.

 

do a compression test. check your plugs. sometimes a gap that is too large can cause high end/high load missfires.

 

Check your Catalytic converter. I ran into the same problem in my Integra and that's what the problem was

 

getting a hollowed cat tomorrow to try in place of it.

 

Remove the cam gear and sell it. No point since its a stock engine

 

^yup

 

took the stock cat off yesterday and it looks brand new inside.

and the head is a y7 head so ill keep the cam gear on it.

 

took ecu out and found out it was chipped. ive tried other ecu's that i assume were stock and the engine wouldnt rev past 2500. so it appears that my sedan only runs on chipped ecu's.

 

also did some more research on the b2/y7 mini me and i did not realize you need to run the 88-95 civic cam gear. not the y7 cam gear. my adjustable gear was set to be the same as the y7.

im hoping now that this really fixes the problem.