Turbo Grand prix Wont Start

[3XTurboAgain]

This car ran pretty nice last night for the first time. It wont start back up ive replaced ICM wires and plugs, 30lb injectors, 3100 topend, new crank sensor. Check engine was on when it ran. the motors brand new 30 over and this is really pissing me off. Anyone can help please drop in! thanks A lot

[Joseph Upson]

This car ran pretty nice last night for the first time. It wont start back up ive replaced ICM wires and plugs, 30lb injectors, 3100 topend, new crank sensor. Check engine was on when it ran. the motors brand new 30 over and this is really pissing me off. Anyone can help please drop in! thanks A lot

Diagnose. First you have to do the simple checks to determine whether the engine is not running because there is no spark or no fuel. Pull a plug wire and watch for a spark during a start attempt, turn the ignition on and listen for the fuel pump to prime since the engine light was on check for a code.

[IsaacHayes]

30lb injectors? Did you burn a new chip re-calibrated for those bigger injectors? If not then it would be flooding out with them.

[3XTurboAgain]

Yea i had a chip burnt to calibrate the 30 lbs injectors. Im going to try to ohm the ICM harness and unplug the KS to see if the harness is good. I have to check the system out before i conclude its the chip. I dont understand how it ran descent and then sputters out and now doesnt have spark. Its either gotta be a pinched harness, you never know with a 17 year old car or the computer chip is half erased? If it ran good on first start, that means closed loop is working? Then when it warmed up could it have gone into a defected open loop mode and start crapping out, erasing the chip with it? Just trying to think of any possibility. Check engine was on when car ran but only throws 12.

[toadson]

re

How old is your battery? Ive seen cars with crappy batterys that had enough juice to crank over, but not enough voltage to actually get the thing running. You could try jumping it I guess if your battery is really old, but its just an idea. As far as your chip getting erased, I dont see how that would be possible. It could be some bad wiring somewhere, but that almost never happens from my experience. If you think the wiring could be the culprit, check around hot engine parts, like the exhaust manifolds, and make sure no wires got melted and are shorting out. Keep us updated.

[3XTurboAgain]

OK heres an update: The car starts up on its own now. I think i have an injector problem now. The car runs like it has clogged injectors. If anyone here knows what a 3.1 feels like with crappy injectors, this is it. I think i tried starting it too many times not knowing there was no gas in it. ( my gas gauge is decieving). I figured this out because instead of gas, i was getting air out of my fuel rail . Put gas in a primed the air out now the car runs but i think i screwed the injectors up. This sucks because now im thinking about mail the injectors back and having them ultrasounded or flow tested. The car lacks power all around but does run and rev. Idle is weak as hell and sounds like theres a potato in the tail pipes haha. Anyone else think i coulda screwed up the injectors now? Everything is new under the hood. Thanks!!

[prophiseer]

no . . . sounds to me like the fuel pump is starting to go bad, not wanting to start the motor, getting nothing out of the fuel rail; poor idle with those other symptoms says to me that the fuel pump isn't providing enough psi for those 30# to keep running. Hook up a fuel pressure test gauge to the test port on the fuel rail and check your idle psi. You should see at least 40 psi on a stock pump - if it's within 30psi, I'd recommend grabbing an adjustable FPR so that you can set you're WOT fuel pressure. You might need a higher flowing pump, also.

If fuel pressure is below 30, then yeah, you've got a pump problem.

[3XTurboAgain]

Hey, Heres another update. I found the problem , cylinder 4 has zero compression! I just put the motor back together but never pressure tested the heads... not sure if its a crack or burnt valve or, something stupid? Im positive the gauge works too. Thanks a lot guys/

[3XTurboAgain]

OK this thread is done it was a bent valve. Oh well live and learn. I just swapped a spare head and it will run nice tomorrow thanks everyone for helping out.