My 3.4 Won't Run!!!

[dohcfiend]

iirc the 5v reference is on terminal a

did you see fuel coming ot of it?

[Sonyman]

would my tps be an issue even if no trouble codes came up for a faulty tps?

[grandprixgtp_91]

well if your car doesnt run it doesnt know its bad.

Jake

[Sonyman]

To re-cap and update: Today before doing anything i attempted to crank up the car and it ran for about 10 minutes total. It started out strong then started missing, stalled and die. It cranked up again after 10 minutes waiting but died less than a minute later. I took out the fuel rail to see if fuel sprayed when cranking, nothing during cranking but when i stopped cranking, they spit a fine fist once. It did this an avg. 3 of 10 times. I noticed on injector formed slow drops of fuel when pressurized. I checked for spark by pulling a spark boot out laying next to a plenum bolt. Sparks occurred nicely. While the engine ran earlier, it popped up a code 34 which is MAP sensor. I tried 2 other sensors, same effect. Now what???? Take your time...i got plenty except i gotta get it running before the end of the month.

[grandprixgtp_91]

when the car stalled out, did you check the spark then? becuase if you lost spark when it stalled then im going to lean towards crank sensor, i know you said you changed it, but id try again, and with gm parts if you didnt use them

Jake

[Sonyman]

I didnt check for a spark after it stalled at the beginning but i did after i did fuel check and once more before i called it a day. the crank sensor was from auto zone. a while back i hooked a multitester to the wire harness to the crank sensor; as i turned the engine, the needle moved as it moved as TDC on #1 cylinder. So from that i assumed it's all good especially since it cranked up this morning.

[grandprixgtp_91]

yes, but ive seen crank sensors mess up when they warm up.

Jake

[Sonyman]

so you suggest i buy a "GM" crank sensor part?

[grandprixgtp_91]

no, im saying check for spark when the car dies out when it warms and if you loose spark then maybe buy a gm one if the connectors are good.

Jake

[dohcfiend]

yes, but ive seen crank sensors mess up when they warm up.

Jake

x2

sometimes they crack and when it is cold, it runs fine but when it heats up the crack expands allowing abnormal operation.

the only real way to check one is with an o-scope. hell i am a lvl 2 electronics tech and i do not even have one. they are high as hell and my boss is cheap.

when you crank, you should see uniform sign waves but if the waves spike like mountain peaks, the part is bad(not that it matters).

anyway, you need a meter to check the TPS and MAP or just replace them and hope, your call. TPS is cheap $20 for an advanced auto one, i do not believe the MAP is so cheap. JY is free if you have the pockets and the ballz.

[Sonyman]

gotcha but lets assume the sensor is ok, then what? As long as i have deal with this car, i should have a few gray hairs in my head by now but i feel i'm almost there of finding the little bastard thats causing this big 3.4 from working! Damn near 80%of everything is new, there's not really not much else to diagnoise i feel unless something has lied while it was tested made me to look elsewhere. In short i feel its a simple engine problem inspite of the BIG problem its causing me.

[Sonyman]

i'm gonna get a new tps and MAP this weekend for sure. So what its going to end up is all sensors on the engine will be new. therefore if the engine still doesnt work, then it must be the communication links (wiring).

[grandprixgtp_91]

hard to say, could be a bad wire, you might need a junkyard engine harness,

did you replace the crank sensor before or after all your problem?

Jake

[grandprixgtp_91]

dont waste your money on aftermarket junk sensors, we see enough problems with them at work, spend the little extra and go gm.

Jake

[Sonyman]

it was replaced a year ago brand new