I have a 2006 GMC LBZ Duramax with 25k miles. It starts great when it is cold and glow plug light goes out. Shut it off and restart it in less than about 15 minutes and it works great. However if you wait any longer it will not start until the engine is completely cool and the glow plug light comes on again, usually about 5 or 6 hours. I changed the fuel filter and primed but it did not solve the problem. Absolutely no fuel leaks that I can see.

It is past the 36 month warranty. I do not know if repairs would qualify under the emissions warranty. Maybe it is simple?
Just Need Help!!!!!!!!!!:eek:

did it loose its prime. what type fuel filters are you using. if you let it run and come back and see it yopu have fuel up by the fuel filter and use the primer pump and see if it starts up.

I do not think it lost its prime. The old filter had been in about 4000 miles and was an AC Delco, new one is an AC Delco. It just happened yesterday. I had driven it 10 miles shut it off for about 20 minutes and it would not start. Left it where it was at overnight and went back this morning and it started right up. Drove it home, shut it off and started it right up, shut it off for another 20 minutes and it would not start. Put in new fuel filter and primed it correctly and it still would not start. Left it for 5 hours and it started right up, drove it for about 20 minutes, shut it off, waited a few minutes and it started right up, shut it off again and waited about another 15 minutes and it would not start. Just tried it now after about 6 hours and it started right up. Go figure, I am stumped.

There is fuel at the primer pump bleed when it will not start.

have any engine codes. do you have strong batterys. you might check your battery termnals. (they might need to be cleaned) theres only 3 things that you need to keep a diesel running thats BATTERYS, FUEL, and COMPRESSION. to me is sound like a fuel problem.

I have a 2006 GMC LBZ Duramax with 25k miles. It starts great when it is cold and glow plug light goes out. Shut it off and restart it in less than about 15 minutes and it works great. However if you wait any longer it will not start until the engine is completely cool and the glow plug light comes on again, usually about 5 or 6 hours. I changed the fuel filter and primed but it did not solve the problem. Absolutely no fuel leaks that I can see.

It is past the 36 month warranty. I do not know if repairs would qualify under the emissions warranty. Maybe it is simple?
Just Need Help!!!!!!!!!!:eek:

Duramax is under warranty for 100k, take it to the dealer.

The batterys seems as though they are all the way up, when it cranks it does it effortlessly. I do not have it chipped or reprogramed so I do not know if I have any trouble codes. There has been no check engine light. My first thought was fuel, that is why I did a filter change. It also happened after a fill up. I still believe that fuel has to be the culprit and that something odd has happened.

I would think it has to be fairly simple. Guess it will go into the dealer on monday and yes I hope it is under warranty. I will take it out and drive it today since I have not driven it since I changed the filter.

When I get a few more bucks in my pocket I will get an Edge Juice/Attitude. All comments on performance mods welcome. I tow a 28' race trailer with the truck.

Sounds more and more like bad fuel maybe.

If it was bad fuel why would it start when it is cold and not hot? You would think it would be the other way around. Bad fuel would prove difficult to compress and ignite. The warmer the engine the more efficent it would be at combustion. Am I wrong?

I will not write off any scenario.

what about the starter/solonoid ?

It is not a starter problem. It cranks great. It does act like it is not getting fuel. Like I say, you have to wait for the engine to cool to the point the glow plugs come back on. Then it starts right up. It is only when you wait about 15 to 20 minutes after shutting the enine off that it will not start, but cranks just fine.

Just a wierd problem that anyone could face. At least when it happened I was not in the woods. Could have been a long cold Colorado night sleeping in the truck.

Are you sure you didn't put gas in during the fill up? I had this happen, I filled partially up, less than half a tank. It would run and stall intermittently. Drain off your water separator on the fuel filter and smell if it is gas. It will also run for a short time after this, and then begin stalling again.

have you had you truck in for a recall on the glow plug controler. if not you might want to check your dealer about that. but again if your under 100K take it to your dealer it should be covered under that.

It definately does not have gas in the fuel. Changed the fuel filter as soon as the no restart problem happened. The Glow plug recall has been done.

Keep in mind it does not stall. It runs great, It will just not restart if you let it set more than 15 - 20 minutes after the engine is warm.

This has to be something so simple is what is frustrating.

Did the fuel drain back in to the tank. do you know if you lost prime.

Not to get off this topic but this is the first ive heard of a glowplug recall, is this all LBZ's?

All early LBZ's if I am not mistaken need to have the glow plug controller reprogramed. Many dealers did it before delivery. Your dealer can use your vin to check if it has been done.

I am leaning strongly in the favor that I may have gotten some bad fuel. Can anyone out there give me more ideas.

OKAY EVERYONE; HERE IS MY REASONING

When a diesel engine is cold you need warmth in the cylinders to burn the diesel fuel on the compression stroke, this warming or heat function is provided by the glow plugs or a heating element in the air cleaner.

When my engine is fully warmed up I can shut it off and it will restart if I only wait a few minutes. Maybe this is because there is still sufficent heat being retained in the cylinders that will still burn crappy fuel.

If I wait 15 - 20 minutes or longer it will not start. Yes, it still cranks great. The engine temp sensor is saying the engine is warm enough so it is not necessary for the computer to turn on the glow plugs. However if the fuel is junk, low quality or what ever it may require extra heat to start that is not there because the cylinders have cooled just a bit.

I wait long enough and the computer finally says turn on the glow plugs and it starts. Why, it has the extra heat needed to burn the crap diesel.

Of couse this scenario would not be covered under warranty and the dealer would have their hand out looking for 200 bucks would be my guess.

Give your input everyone.

i have the LLY in my 06 but i was told there was a recall on the glow plug controller from 06 and up. i had mine done in jan 07

Not to get off this topic but this is the first ive heard of a glowplug recall, is this all LBZ's?

it sound like you have a sensor problem with the glow plugs. i know there has to be a sensor for them.

The glow plug sensor works of engine heat. It is turned off and on by the computer as well as being timed by the computer.

My problem happened after filling up with 20 gals of diesel. I drove about 20 miles home and shut the truck off. I need to go run an errand and the tuck had trouble starting. It had sat maybe 20 minutes.

The next day it started fine but I did not shut it off on my trip.

A few days later I drove to a friends house and shut it off. We talked for about an hour and when I went to leave it would not start. I checked to make sure it had fuel at the bleed screw on the filter housing and it did. Went back the next morning and it started right up. Took home and shut it off, waited a minute or so and it restarted ASAP, waited 20 minutes and no luck. Change fuel filter and no luck starting. Waited 6 hours and it fired ASAP. Shut it off and it restarted. Buttttttttt let it sit too long and it will not start.

I am still thinking crappy fuel.

now it sounds like water in the fuel run it and then let it sit for that time and use the drain and see if water comes out of the drain its on the bottom of the fuel filter.

I have checked the water drain in the bottom of the filter, there was none there before I put on the new filter and is still none there after checking the new filter.

If there was water present the problem would be consistent; cold, warm or hot I would think.

wow you really got me on this one i dont know what it could be. i guess if you just going in for about 15-20 mins i would leave it running so then you dont have that problem not starting up :lol:

What is the ambient outside temperature out of curiosity?

I tend to think this is fuel delivery related. Something is not telling the injectors to fire when the engine is warm and cranking. This really doesn't sound like a fuel filter issue if it starts fine when its cold.

The times it happened it was about 50 degrees outside. The morning I went back to pick it up was just a little under 40 and it started right away. I have not messed with it today because it has been 20 outside all day.

Why would the injectors fire up to about 5 minutes after it it shut off but not much longer after that, then work again when it is cold?

granted i know that you are running a dmax. but i work in a diesel shop and we see this alot in the dodge cummins. they will crank rite up when they are cold and run perfect. if you kill them when they are hot if you dont try to crank it prety quick they wont start back up until they are cooled off completely. i know on them that it means the injection pump is bad. that is the vp44 injection pump....i dont know if the same thing could happen to the cp3 or not. but i thought i would give that little bit of info wether it be good or bad.

but il be watching this thread to see the final outcome
good luck!

Sounds exactly like my problem. Can you give me some insight why a bad injector pump would cause the odd starting situation. Are there any other symptoms I may not have noticed? Thursday I will take it into the dealer as I am aways out of town.

Your response is greatly appreciated.

Sounds exactly like my problem. Can you give me some insight why a bad injector pump would cause the odd starting situation. Are there any other symptoms I may not have noticed? Thursday I will take it into the dealer as I am aways out of town.

Your response is greatly appreciated.


Have you scanned for codes yet? that is where I would start.

Do you have a tuner or other mods?? :D