Hey Guys,

I have a 1994 Hummer H1 6.5L Diesel and we have been trying for a month to diagnose and fix this problem.

When the truck is cold it starts fine and runs well. Once it has been run for a bit and gets hot and you turn it off it will not restart.

The glo plug indicator will not light up until it cools off. With out the glow indicator cycling at least twice the truck wont start.

We have replaced all of the following trying to fix this to no avail:

New Injectors
New Injector Pump
New Glo Plugs
New Glow Plug Relay
New Fuel Pump
New Fuel Lines
New Thermostat

It is as If you pour cold water on it it will glo and start again in like 10 minutes, otherwise it takes an hour till it cools down before the glo will come back on and then it fires right up.

Is their a sensor we are missing or something...

We are stumped? Figured someone here might now. Please any help is appreciated.

Brad in Rhode Island

 

The glow plug circuit does not normally come on for a hot engine.
A diesel engine is harder to start as the engine gets older. It takes more rpm to generate ignition temperature because of ring or cylinder wear.

Check your rpm with a scangauge when the engine is cold and hot. My hot engine will fire at around 650 rpm, my cold engine maybe when it hits 600 rpm. Your issue is probably battery, cable connections or starter motor related. You need more rpm on the start.
Gil

 

I have the exact same problem w/ my 1994. When hot, you literally have to pour cold water on it to restart or wait an hour+. Any solution? "Experts" have had me try all types of things, even running a new battery ground. guys, selling injector pumps say it is the injector pump if pouring water on it works but you say you have replaced yours? was the replacement new?


Have you fixed yours?