I have a stock p28 on a gsr swap and upgraded fuel system . Stainless braided from firewall to str/bdl fuel with aem FPR stock setting with vacuum hooked up , braided back to return line. ALso have the breather line exposed , no canister. When i turn the key on i hear the fuel pump kick on , i try to start and it will stumble and shut off , sometimes dont start at all first try. If i key it a few times and get the pressure built up i guess, it will then start normally most of the time. What would cause this? Is it the p28 not giving the initial pulse to the injector not good enough? Or does my aftermarket fuel system have something to do with it? Also does anyone know what kinda fuel pressure i should have with this. This is just a temporary ecu to work these kinda details out before i put the AEM ecu in.

 

try to get a GSR ecu or at least an ecu for a DOHC motor. I don't know what else to sy except that you are trying to run that motor with a 1.6L SOHC program so that could be the cause.