Hummer wont start

[Am General]

Hey guys. I'm helping the guy that bought my old H1 try to get it running. Heres the scenario. 2001 H1 6.5 TD. Has upgraded computer and 4'' exhaust. Truck cranks but wont fire. It REALLY wants to but it just wont. While cranking smoke is coming from exaust (getting fuel, right?) 2 or so years ago the PMD was replaced with a used ebay one to see if that would fix stalling issue. It did and was remote mounted on a heatsink. For diagnostic purposes I plugged the old one back in. Still no start. Lift pump good. Filter housing drained and bled. ESO solenoid does click with IGN on. Crank rpms close to 100 (as per Snap on MT2500 scan tool). Codes present: 0380 glow plug circuit perfomance. I have not verified voltage to plugs but have verified voltage to controller with test light (didn't have my meter with me) On the scanner glow plug voltage is 2.4v. Not proper. In my opinion though this glow plug thing means squat since it's over 50 degrees and I had a block heater on the truck for a few hours. I figure it should start even without any glow plugs right? It would be rough and unhappy but I would think it would start. Am I out of line there? I've also posted this on the Hummer board but figured this was more specialized to my issue. I really appreciate any help you guys can offer.

Adam

[john8662]

I'd figure a way to hotwire the plugs to on momentarily, sounds solely like a lack of glow. I've seen engines not start due to no plugs working, even when using the block heater.

J

[DmaxMaverick]

If you had the fuel system open since it last ran, it could be significant air still in the system. You've gone this far, priming and cranking, so it should start. Try loosening all the injector line nuts you can reach at the injectors (about 1 turn). Crank until all the loose nuts are wet with fuel. Tighten them all, and try again. Make an effort to keep the batteries well charged, and don't fry the starter. No more than about 20 seconds of cranking, with at least 2 minutes between attempts. If it still doesn't start, you may have a glow plug system problem, so read on.

The P0380 is a pretty good indicator the plugs aren't getting enough voltage, the controller is not operating, or too few plugs are good (low amp draw).

They won't start on #2 fuel w/o the glow plugs unless the block is warm (like within an hour or 2 after a hot shutdown). (DO NOT use starting fluid/ether!) It sounds like the plugs aren't getting juice, for one reason or another, or there aren't enough good plugs to get it to fire off. If you are getting smoke while cranking, the fuel is there. It should at least try to start, unless there isn't enough cylinder heat. If you plug in the block heater for 2-3 hours summer, 4 hours winter, it should warm it enough to allow a start. Either way, you'll have to figure out if the plugs are heating. Is the GP (or WTS) lamp on the dash coming on? If so, the controller is working, to some degree. If the harness is OEM, you will also have a fusible link at each bank of GP's. Check for battery voltage at the plugs during the glow cycle. If you have voltage, then check each plug for continuity. Test light, or VOM, with the plug spades disconnected. You should get 12V is this is a civi model.

Keep in mind, with all this cranking, your cylinders may be very wet with fuel. Be prepared for an initial burst of RPM when it starts. Fortunately, with all the cranking, the oil should be pretty well distributed, and oil pressure should come up rather quick. It may sound off loud, with a lot of rattle (and smoke), but should settle into an idle within a second or two.

[trbankii]

I'll put another vote in for getting the glow plug situation fixed. Different engine, but I acquired an old Bobcat excavator this past year. I'm slowly fixing it up, but the engine really hadn't been much of a problem so I was working on other things. Back in August I was having exactly the symptoms you describe - cranking, wanted to start but just can't seem to, and puffs of white smoke out the exhaust. Finally tracked it down to a glow plug issue after spending a lot of time thinking it couldn't be that since it was August for petesake...

[Am General]

Well fellas heres the update. I know it's been a while but I hate when people ask questions, solve a problem and don't follow up so here goes. The reason why this truck did not start was the AC compressor! Go figure! I don't know what I was thinking when I first looked at the scanner at the crank speed but it was not fast enough even with strong batteries. The ac bearing was completely seized. There was enough friction on the pulleys to not allow a fast enough crank speed to fire. That explained why it wanted to so bad but just wouldn't go. Once the belt was removed (and a good pmd plugged back in) it fired up even with a bad glow plug. I later traced down the number 3 glow plug to be bad and replaced that. Now it runs and drives like a champ with no check engine light. Figured ya'll would like to know.