OK so I have a 91 camaro, I just put in a new fuel pump, it has a brand new airfilter, fuel filter, transmission (out of a scrap yard), starter. altinator, battery, all the sensors(for the most part), new water pump, all brand new gaskets, heads where researfaced, because of a blown gasket, all brand knew fluids, not sure if im forgeting something... But what im geting down to, is my TBI back fires, My fuel pump syphons gas out of the vent line, if i put the gas cap on, would that mess with the pressure that the lines send to the tbi? and also why is my pump, or tank geting so much pressure its spewing out gas from the vent line, should i check the work i did in the tank? Any advice or tips on how to figure out this problem would be nice, i dont have a pressure tester, but im sooo close to investing in one. It starts up fine, idles fine, after alittle bit of idleing and i give it gas it will just back fire, stall, and when it back fires, it shoots gas up from the tbi!! why does that occur?!?! Thanks in advance

 

Atm i have the gas cap off because it gets so pressurized im assumeing, and it starts shooting gas out of the vent line, and it only has maybe a quarter of gas in the tank, but if i put the cap on, it does that( or did that I havent put it back on in fear it will do it again with out haveing solved the problem) could it be the way i installed the fuel pump? =o It was pretty cut and dry i know i didnt mess anything up, so its kinda stumping me as to why thats happening, and why its back fireing like that

 

Ah yes not to mention new spark plugs, cap, rotor.. i think that may be it

 

sounds to me like you have your timing off,maybe 180 out,not clear on the fuel pressure question,could you have installed a tpi pump instead of tbi?? way big difference in gph

 

I wanna say it is for a tbi, but now that u bring that up im not 100%, I dont get why it was spewing out gas from the vent line, i was gonna just replace the sending unit, but its close to 200$ itself -.- which i dont quite have that kinda money to throw around atm

 

I have the box for the pump, and the reciept, im gonna go look it up and find out if it is for tbi or tpi.

 

I am not sure, it doesnt say specifically on the box, or on the site, this is what i got and put in though http://shop.advanceautoparts.com/web...___#fragment-3

 

your timing is off. not so much the distributor timing but the cam timing may actually be off.
either pump can be used btw. the regulator regulates the pressure not so much the pump. the pump just puts out more volume. i think your throttle body has flooded over and gas poured into the vent line then when it vented the gas came out.

 

How is my cam timeing off =[ I didnt do anything to mess with that, that i know of, i took the engine out, and replaced the oil pump/screen as well, but i never messed with the cam at all, is it possible that i could have turned it? or something, i never touched the cam crank, pistons, main barrings, nothing in the block itself, could i sitll have messed up the timeing though? =o