latindragons

Ok, I searched and found a thread that this may be fuel pressure related but thought I'd ask for my specific case.

I have a 1995 Trans Am and I've been having problems with the start-up lately. Basically, after the car's been sitting for a while I'll go to turn it on and it'll crank for awhile before turning on (varies from ~3 seconds to as long as ~30 seconds).

After it starts (finally) it may die immediately or drop in RPM then go back to normal. Then I'll have to let it sit a bit before moving because when I give it throttle, it'll sputter and try to die. After a few minutes, it'll be perfectly normal. Can go WOT, blip the throttle, drive, anything and it'll be fine. It's just the initial start-up.

Sorry for the long post, but I wanted to give anyone as many of the symptoms as possible. I've changed the plugs and just did the cap and rotor (hoping it's not the opti just yet). And changed out the fuel pump maybe a year ago.

Any suggestions are welcome. Thanks is advance guys!

MTBSully

iTrader: (7)

only way to tell is to get a fuel pressure gauge which can be had for around $35 at autozone. A very good investment if you ask me. I was having the EXACT same problem as you with my car. I went out and bought the fuel pressure guage, and found that i had zero fuel pressure after priming, and around 20psi while idling, which is obviously very low.

latindragons

That's what I was thinking, too. Just wanted to hear it from other guys. I'll go ahead and pick one up and try it.
So....this is going to be stupid, but I'm used to carburated cars, how would you use the gauge? And what reading should I be looking for? Sorry if I sound stupid haha. But we all started off ignorant so have pity haha

killagt

iTrader: (3)

my fuel pressure jump to 47-50 psi after priming, its normal ?

trippinholyman

on the back of the intake manifold, the back part of the fuel rail on the driver side i think, there is a schrader valve. just get a normal valve stem removal tool (IMPORTANT! MAKE SURE YOU RELIEVE FUEL PRESSURE BY REMOVING GAS CAP AND PUSHING SCHRADER VALVE IN!!!!!!!!!) and remove the schrader valve from the fuel rail (this is the test port). plug the gauge in there make sure its sealed and all. prime the system, see what the pressure is.

for lt1 cars, normal primed is 41-47. normal idle is anywhere from 3-10 psi less than that.

if its low, check for a clogged fuel filter, clogs in the lines or bends anywhere (like when you kink a hose).

worst case scenario you might need a new fuel pump. make sure you cut the trap door though that way itll be easier in the future! http://www.taekwondoplus.org/z28/fuelpump.html

http://shbox.com/1/fp_reg.jpg

thats a pic of the fuel pressure regulator / schrader valve

check your reg too its quick and easy

latindragons

Thanks a lot Trippin and MTB!! That's exactly what I needed. I'll try that out and see if it works.

MTBSully

iTrader: (7)

let us know how it goes!