just put a fresh motor in my firebird.. it has 10-1 comp. 30 over..cam 521-540 lift 236-242 dur. 1.5 rockers bbk 54mm.. stock mass..stock heads with vlave job. all new head hardware.. fuel inj. 10.4 wires with msd ing.. full header back exsht.My problem now is when i try to start the car it will start up after a few trys and it will idea for about anymore from 30 sec to 2 min... but as soon as you hit the gas to rev it up the motor dies its like you are hitting a kill switch nothing to poping or back firing the car sounds good.. but i think it is getting to much fuel the gauge is reading about 48psi i know that it is burning your eyes.. when i first start the car the idea revs up and then it goes back down.. when will give it more fuel pres. one the idea goes up and then the car will shut off... i got my pcm programed from madz28.. i am not sure if it is a pcm problem or if the cam is too big for it or what.. i know is that i got over 10,000 into the motor and all and it really makes me upset that it is not runing... can you please give me some help on what might be.. its getting fuel air and spark but its just not runing right there is something that is dif. wrong

 

That fuel pressure sounds a little high, but I wouldn't think it would cause the engine to die. I know it sounds obvious, but double check all electrical and vacuum connections. Are you getting an SES light? I believe a MAP sensor could cause a problem like that, but so could a hundred other things. Check it over with a fine tooth comb and let us know if you find anything. I know theres a ton of stuff to keep track of when you do an engine in one of these cars, so just keep at it. You'll find the problem!

 

Check your MAF.

 

i checked all the vac lines and the maf is all hooked up and pluged in..IF i LEAVE THAT hooked up the car will do the samething and if i take it off the car will still do the samething..If i take my tps sensor out the car will run alittle longer.. if i take out my air temp sensor it seems the car will run alittle better.. what should the right psi should be. and My main cons. is the cam to big for the car because that is what alot of people are saying around me.. Or could it be a pcm prog. problem...i think the inj are 36# but i am not sure.. its been along time since i got them..

 

It is a pretty healthy cam that you describe, but certainly not too big for a 355 cid. You may not find it to be such nicely mannered as you may want though, since the cam will produce less than 10 inches of Vacc, and some serious lope.

Make sure that those injectors really are 36#'s and got programmed at that rating.

First off, if you got access to a scanner such as Datamaster, it will go a long way in diagnosing the problem. First things to check is if your IAC is maxed out at 160 or anything close, and check to see that your idle rpm is at least 900 rpm, aprox 1000 rpm will feel smoother. If your IAC is stuck at such a high number, it means you car either needs more AIR at idle, or is drowning with fuel.

Clear the basic things first, such as checking if you have any pcm fault codes.

 

I agree get a hold of datamaster. I think the guy who mentioned hte MAP sensor mayb be on to something but no wya to know without either simply replacing it or scanning the car.

Am I understanding correctly that when you UNPLUG the MAF it does the same thing?

 

Check to make sure your TPS (throttle position sensor) is hooked up and working properly.

-Dave C. '97 Z28

 

Does it idle smoothly?

 

yea i got the injectors off a buddy they where in his 85 iroc they are from ford racing and he said they where 36# but there is no way to really find out how big they are is there.......i really dont know anybody around me that works on lt-1s but all old 350... the datamaster.. is there somewhere i can buy it or just get my hands on the tool...when i start the car with or without the sensors. ill take off my cold-air my elbow everything the car will still start up and run the same just like if everything was hooked up.. i did see on my fuel gauge the the psi. will drop down to 0 psi as soon as the relay turns off... i read in the heans book that it shouldn't do that....when i get the car to idle it sounds good, sometimes at idle the engine is shanking real bad.... but it will only run no more then a minute or so... I was thinking since its a new bbk throttle bodie if that could be the problem..

if i has the tps sensor hooked up or not it does nothing for the problem

 

When the fuel pump primer goes off, the fuel pressure should never drop to zero like you described. It should take more than a days worth. I would check for a leaking fuel pressure regulator. Check to see if your regulator vaccumm line is wet/leaking. It sounds like your sucking in fuel into your intake manifold directly. If so, make sure you change your oil before you start that sucker, because if it was severe enough it could significantly dilute your oil and scratch your cylinder walls and wear out your engine bearings.