so i have built a nice little gsr engine and swapped it into my 95 hatch..
so ive got everything done and the car is running and will idol fine but when you have it some gas at like 3000 rpm it starts to miss fire a little bit.

im running 12.2:1 and im using a stock fuel pressure regulator... so i think im running to lean.. anyone have any idea..

i have heard something about maybe retarding or advancing my timing.. but i am not to sure! input is way needed!

 

have you had it tuned? you cant run a stock base map ecu w/ a built motor... everything is different. (afr, timing, etc)

also what fuel pump are you running and what injectors? that can be a big deal as well.

 

Also what kind of gas are you using, I would suggest a MINIMUM 92 octane, but 12+ compression would be e85.

And 93eg is right, everything changes once you start adding to a stock motor (which yours sounds far from).

 

i have not had it tuned yet.. i was told to do a break in period of like 2000 miles..
as for a fuel pump i switched to an itr furl pump and stock gsr injectors..

and i have had a decent amount of work done to my engine..
block and head machined .010, bored .020 over , oversized valves, dual valve springs, ctr cams, skunk 2 intake, i used pr3 pistons on cnc rods .

so my engine is legit i just have to figure out this fuel problem.

 

You should have at least got a base tune or something....

Pull your plugs and see what color they are? My bet is your runing lean

 

Which ECU are you using? The misfire could be caused by several variables: timing, running rich or lean and incorrect ignition pattern.

 

i am using a chipped p72 with an itr base map right now

i check my dizzy and i have the order correct.

i just ordered an adj. fuel pressure regulator today. so im thinking i need to add some fuel to compensate for the higher compression.. the exhaust smells like its running a little lean..

does anyone know anything about the timing tho? like advancing or retarding it? im talking spark and cam...

 

running a built motor even for a break in period w/o an improved basemap to support your mods can lead to catastrophic failure in a hurry. running high compression lean on gas can lead to melted pistons and things of that sort. i would get you AFR figured out and i bet you will have a better running car

 

thats what im thinking to!
any ideas of what kinda psi i should be running on my new fuel reg.?

 

anyone?