I got a 89 civic si with a b20b obd1 converted , car has chipped ecu ( ran fine at first) , walbro 255 pump, stock inject. The car runs bad when its first started up, It misses, hesitates. Even after it warms up it still acts like it misses a little. it does throw a cel once in a while but I cant check it because after i turn the car off it doesnt come back on....any ideas? Car has a new magnaflow high flow cat on it...I smell fuel when I start the car , its 100%% Running rich. It has a 4 wire 02 , ( I dont know the condition of it. I have had it for a while ) would unplugging the 02 sensor be a way to test it?? Im lost ....

 

ttt

 

anyone?

 

No one has any idea?

 

unplugging the o2 isn't going to do anything for you, since cold starts are open loop. i would double check the map on the ecu.

 

You meen as in the tune? I just dont understand why it ran fine for the first month? I would have thought if it was the tune it would of ran like crap from day one...?

 

need help still

 

Maybe your timing belt skipped a tooth.

 

Never thought about that, I highly doubt it, I dont beat on the car, It runs , my mpg is really crappy and it has a weird miss at partial throttle

 

Most likely your timing is off / you don't have to run the car like its a race car for it to get off timing / over the years your timing belt needs to be replaced because it stretches and can jump a tooth or your tenshioner can get loose after a while and just needs to be tightened have a timing check on your car

 

Check the CEL code with the engine still running.

 

not sure how to check it on my obd1 converted ef? The plug is NOT under the dash by the glovebox. The car is a 89 Si

 

I have the same kind of problem with my obd1 b20b4 eg but my hesitation is only under 3k rpm. A shop told me it's the LS base map I'm running on my chipped p28 and that i need a tune.

 

What program is it? o2 won't do anything. Motors also change conditions causing the need for a new tune. This is assuming everything on the motor is good

Temp, it's a junk ls base map.