Driving my 98 H1 home with a 6.5 TD
Wagon and it just quit. There was a bang sound but no signs of damage (i.e. Holes with Pistons sticking out)
The engine turns over, there fuel to the fuel filter, the fuel pump is working just fine. I have relocated the PMD about two years ago, all the wires are still connected.
Just need ideas of what to look for?

Thanks in advance
Bergie

 

Need more info. Did the engine shut down and will not restart. Will it run and make a horable noise. Is it smoking while cranking( it should be if your pmd is still good). Are you leaking coolant on ground or into the egnine oil. Will the truck roll freely or not? What does it do when you try and crank the engine- no crank- crank but no start-horable noise while cranking? Do you have exhaust coming out the coolant resivor( run with no radiator cap on it)?

 

Not sure about the bang. Any fluids in the valley of the block? You have fuel to the lift pump, are you getting fuel through the injection pump?

 

When the H1 quit there was a bang sound
I will check the thing you listed and repost

Thanks for the ideas to look for
And give you-all more info later
Bergie

 

My brothers did what yours is doing. He had a small hole in a fuel line down in the valley of the motor. It was leaking some fuel and sucking air into the system and couldn't get it started for anything. Replaced the line and the issue was gone.

 

3 hummers brother probably had a pre 1996 engine. The earlier fuel systems do not use a fuel lift pump. A fuel suction leak between the tank and the fuel pump (either electric lift pump or mechanical fuel injection pump) will have bubbles in a fuel line. All hummer owners should have some clear fuel hose for troubleshooting. Most clear hose is crapy- it will break down over time and not hold a lot of pressure. Some will get hard and brittle and some soft and almost gooey. Only use clear hose for troubleshooting air bubbles getting into fuel system. Still need more info on the symptoms.

 

He has a 95. Lift and injection pump, no PMD.

 

Thanks to all of you ideas
I found the problem. I had and old PMD unit laying around so I plugged that in and she started.
It's a bad PMD unit.
In the past then the PMD would go out the vehicle would always restart, not this time. So I will order a new one, problem solved

Thanks for all you great ideas
Bergie

 

Order two new pmd's and test the spare before throwing it in the glove box. Remember- new does not mean it is good. I have got plenty of new bad parts out of the box over the years. Big dog offroad has a heavy duty pmd relocate kit with big heatsink that has a lifetime warrenty. A pmd does not cause a bang, it only cuts the fuel and either shuts down the engine or wont start. If you have a nostart condition and while cranking trying to start there is no smoke coming from exhaust its 99.9% a pmd.
If you get smoke out of the exhaust while cranking it is not the pmd.

 

Once your truck's PMD starts to go it is only a matter of time until it dies completely. Usually they will restart for awhile after they have cooled down but the day will come when it is just dead. The relo kit is a good idea if for no other reason than it is much easier to change a PMD that is not buried in the valley of the block. Like Ian said, test your spare, don't assume it is good because it is new. Heat and vibration seem to be the primary culprits in PMD failure.