ok so i have a 86 GXL...i swapped in a large street ported Jspec S4 motor...

with this i have:
microtech LT-10s
modded TB
FMIC w/2.5" piping
3" DP, 3" HKS hyper exhaust
HKS SSQV BOV
stock 550cc inj.
TII drivetrain w/Stage 3 6puck clutch, 1700lb pressure plate

well that's it everything else is stock.

my question is it runs chopy around 3000-4000 like it's igniting, not enough fuel i guess. and on cold starts the AFR's are at 19.

other things...

in vaccum it runs round 14.7, and in boost it jumps between 11.7 and 12...with the occasional jump to 14.

i have a guy who helped me with the build and did the port, and some tuning but he's busy a lot so im trying to do as much to fix this as i can. this stuff is all new to me and I'm sorry if this thread is very Noobish but that's what i am, so please help if you can.

thanks Jay

 

Essentially you need a tuner or need to learn the whole process. There are threads on a variety of boards that cover the process. I usually hate saying it but search. If you want to do it yourself and learn there are some good books on the subject. The best I've read is How to Une and Modify Engine Management Systems by Jeff Hartman. Very good read. I'd recommend checking out the Microtech board as well. If you post this same question over there the MT guys will tell you to find a tuner and get it dyno tuned. But if you search and read there is some great info there.

What you're playing with is potentially lethal to your engine so be careful.

 

^^^that's why i want to figure this out because i have too much invested in this for it to pop

thanks a lot though i'll do some searching