Thread: I have spark, fuel and it cranks but no start

I've always read about case learn but I've replaced 5 crank sensors on these cars over the years & never did it once (drove those cars 500k miles). Not to mention I can't actually start the car for it to do the relearn process.

I haven't touched it over the weekend with a million other projects going on.

Things on the to-do list:

- I'm going to check resistance on each injector to see if I have one dead or something that could be a problem.

- Go borrow a fuel pressure gauge to hook up & see that the new pump is operating correctly, the pump does run but I don't know if pressure & volume are correct. Doesn't matter anyway because the injectors aren't firing.

- Cut apart the old fuel filter to figure out which one is supposed to be the inlet & return along with running the pump to see which hose pressure fuel comes out of.

- Double check the security system to make sure it's not locking out the injectors (even though it's not giving me any message it has activated)

How about the fuel pump resistor? It's a pesky issue on the 97-03 GTP's. Not sure about your '04 Comp G. I know that resistor caused me a lot of headaches. Here's a link with useful info:

http://www.grandprixforums.net/threa...sistor-Upgrade

It's my understanding there is no fuel pump resistor on 04+ cars. They run at a single speed. No rising rate FPR either since it's in the tank with the pump.

Have you swapped around relays to check the fuel pump/ injector relays?

Ok... So I got the car to start on about the 3rd time cranking it today. Drove it up the road a few miles & came back. Ran perfectly normal, no CELs. Pulled into the garage & shut it off. Won't restart. This is maddening... Before I tried to start it I checked resistance on all the injectors, they were all between .012-.014 ohms. Put 12V to each injector to see if they're firing, yep. So, we're back to no injector pulses other than the prime cycle. I can't even just crank & crank because it fires enough every time to kick the starter out.

Yes, I've swapped relays around too.

It's gremlins definitely

Damn Gremlins are impossible on this thing.

This is a 2004 GTP

I can get it to start randomly. It will run just fine once it's started. I'm sure it would run the entire tank of gas if I let it. But as soon as I turn off the ignition it will not restart. Typically it starts enough every time to kick out the starter and dies right away. Over & over until the battery is done or I give up. I might come back to it the next day and after a couple prime cycles it will start again. And not restart after I turn it off. I did get the P0336 code again as pending when it was running so I replaced the crank sensor again. Didn't fix it.
-I've cleaned all the grounds, the battery cables, checked all fuses & swapped relays, unplugged & replugged in the computer about 5x to clean the contacts.
-Tried starting it without the MAF plugged in.
-I can see the MAP sensor working when I crank it watching my Torque app (same for rpm & temp, I can also watch the throttle percentage if I step on the pedal).
-It has 60psi of fuel pressure at the rail.
-I've had the ignition module checked and it's fine.
-I've checked the signal from the crank & cam sensors with a multimeter while turning the engine over by hand and checked spark with a timing light on each coil. All works.
-I've disassembled the key to remove the transponder to check to see if the PK3 antitheft system is working correctly - it is, won't crank when I move the transponder away from the ignition switch.

At this point I'm absolutely out of ideas. The only direction I know to go from here is replace the computer. I don't understand how the engine will run perfectly fine when it runs but not start otherwise.

Thanks for all the suggestions so far. At least I'm not losing my mind, yet...

id take the crank cam to icm harness off and inspect it good, looking for any cracks or bare metal showing. repair or replace it if any damage is found.

Thanks Scotty. No gremlins, just a mouse... It was the the crank signal wire from the ICM to the PCM, eaten through on the underside of the connector up on the intake. Couldn't see it until I unplugged it. I had been checking it where it plugs in to the ICM. Mouse must have eaten it at the same time the car was sitting after the fuel pump died.

Soldered it up and starts instantly now. The wire must have been intermittently touching the other part to make a connection & let the car start occasionally.

cool, another win.