96 3.4 DOHC won't start!

[3dale1]

Hi guys, been a long time since I've been here! But, I have a 96 Monte Carlo Z-34 with 314,000 problem free miles, except for a major oil leak at the distributor block off area. However, it is tired, and has been for a long time.

yesterday, I think the car finally gave up. It just shut off on its' own after hiccuping a few times going down the highway and would not refire. Had it towed home and started to look for problems. It has spark on all three coil packs and good fuel pressure. Pulled the top covers off the timing belt, and it looks in good shape. The dots on the cam sprockets line up with each other on both heads.

What could have happened? Any ideas on getting me started in the right direction?

Hate to get rid of her; bought it with 8000 miles in '97. Just how much of a PITA is it for a do it yourselfer to put another engine in if the need be?

Thanks for anything you care to post; I appreciate it!
Joe

[gsEnterpries]

did you check if it has compression? check the fuel pressure while cranking it over too.
To pull the engine out depends on what tools you have.

[Sonyman]

Mann!!!! Have i been there several times. I tell ya these 3.4s is like babies. Cant turn away for a second, they always needs to be burbed or something! But the pay off is all good at the light. dont give up the ship, it motor is on its last leg, rebuild it from within and keep on keepin' on. Our cars is on their way to becoming classics real fast.

[OldSkoolGP]

The first thing I thought when I read this was a dead PCM. The easiest way to test that though is to listen for the fuel pump when you turn the key on. If you hear it, the PCM is OK. If not, check your PCM fuse in the car first. The other thing it could be, being OBD II, is something could have happened to the crank pulley sensor for the fuel timing. If that failed, it wouldn't matter how much fuel pressure you had because the injectors would never get the signal to fire.

How are your testing the coils? Are you checking for spark at the plug wire?

[3dale1]

The first thing I thought when I read this was a dead PCM. The easiest way to test that though is to listen for the fuel pump when you turn the key on. If you hear it, the PCM is OK. If not, check your PCM fuse in the car first. The other thing it could be, being OBD II, is something could have happened to the crank pulley sensor for the fuel timing. If that failed, it wouldn't matter how much fuel pressure you had because the injectors would never get the signal to fire.

How are your testing the coils? Are you checking for spark at the plug wire?

I was thinking along the line of a crank sensor, but wasn't sure how that would impact spark or fuel delivery--no fuel at all at the tip of the injector, just at the rail? Haven't pulled a plug to check for wetness. I can hear the pump fine. Don't know what the rail pressure is exactly (no gauge) but depressing the schrader valve sends plenty gas to the hood.

I checked for spark by putting an old plug on the end of the three front bank wires, and checked the coils by just popping the boot and using a screwdriver to arc the coil to the engine. Plenty of white spark both ways.

[OldSkoolGP]

Sounds like you've got good fuel pressure and spark then. The other thing you could do is hook a volmeter up to the wires for an injector and see if you have any power when you crank the engine. If you don't the injector isn't firing and your problem could be that sensor by the crank pulley. If you do have power at the injector, I'm not sure. I'd have to think on it.