1998 GT 3800 Will not start !!

[suntoy68]

My 3800 has been running fine until night before last. I was setting at a red light, tried to go when the light turned green but she just sputtered and died. Pushed it into a parking lot and left it for the night. The next morning I tried to start it and it kind of backfired through the intake and broke the nose off of the starter.
Well I replaced the starter and I have gone through every test I can find in my Haynes manual and no luck. Still won't start, acts like it is out of time but has plenty of compression so I know it is not physically out of time. Crankshaft sensor gives 3 and 18 pulses as descibed, camshaft sensor shows voltage excpt for one dead pulse as descibed. ICM coil pulses seem fine, all coils fire, fuel pressure is at 50 psi after 2 sec key on.
Help !!!!!!!!!!!!!!!!!!!!!!!!

[blueguy]

SES Light? Sounds like it could a spark issue...your plugs and wires bad? Just a thought...but I don't think plugs and wires would make it back fire out of the intake.

[suntoy68]

SES Light? Sounds like it could a spark issue...your plugs and wires bad? Just a thought...but I don't think plugs and wires would make it back fire out of the intake.

Thanks for your quick response! Yes the SES light came on as it was dying. I thought about the wires/plugs but it didn't make sense to me that they would all go bad at once. The plugs are getting fire, well I pulled #5 plug, grounded it with a jumper cable and turned the engine over and the plug fired. Can you get any info from OBDII after disconnecting the battery ? I did this to replace the starter, now with the car not starting I am unsure whether I can get any data from the PCM or not.

[Lawngoose]

No you cant get data from OBDII without power. At least I cant with my Scangauge II

[suntoy68]

Thanks Lawngoose ! I am not sure I was clear with my post. I have battery power now and can crank the engine. Can I get any OBDII data now ?

[skidoojames151]

sounds like your upper itake went bad and then it hydrauliced which broke the starter...same thing happened to me when my upper intake leaked

[GTPFTW]

Thanks for your quick response! Yes the SES light came on as it was dying. I thought about the wires/plugs but it didn't make sense to me that they would all go bad at once. The plugs are getting fire, well I pulled #5 plug, grounded it with a jumper cable and turned the engine over and the plug fired. Can you get any info from OBDII after disconnecting the battery ? I did this to replace the starter, now with the car not starting I am unsure whether I can get any data from the PCM or not.

Its def not plugs or wires. Pull your coil packs off and underneith is the ignition modual. If you see that its corroded, lightly sand and clean up.

[suntoy68]

sounds like your upper itake went bad and then it hydrauliced which broke the starter...same thing happened to me when my upper intake leaked

Thanks skidoojames you are exactly right, the upper plenum went bad and hydro locked the engine. I have the UIM and LIM off and everything cleaned up. Gathering parts now. FYI if anyone is looking for a UIM, Amazon.com has the Dorman 615-180 for $64 with free ground shipping. It was 129.95 at Autozone ! I think the Dorman part is the best available deal, reinforced around the EGR area, fiberglass reinforced material, reduced diameter ERG pipe to create an air gap between it and the plastic UIM and it comes with all the gaskets, o rings and even a new PVC valve

I plan on using the new GM aluminum LIM gasket set, certainly better than the originals and I think better than the 2nd plastic version. I will post pics and progress later. Thanks all!