We arrived at the campground on Saturday and parked my truck on a hillside next to the FW do my wife could park the Durango for easy use. This morning I went to start the Duramax to pull the portable poop tank to the dump station and all the truck would do is turnover with no start. Checked the Scan Gauge II and no codes. Popped the hood and manually pumped the fuel filter, still no start. Put truck in neutral and rolled it back down the hill and then went inside the FW to break the news to the wife the truck won't start. Meanwhile, unbeknownst to me, my 18 year old son jumps in the truck and it fires right up and he heads off to the dump station. I walk out of the FW and my truck is gone, WTH. First thought did I not put the truck in park and now it's sitting in the lake. Panic sets in and I see my son coming back with the truck, whew, but 15 minutes ago it would not start. My son said it started up after a few seconds of turning over. So, my only guess is that the fuel intake is at the front of the tank and parking on the hill left the intake out of the fuel and the filter drained back to the tank. Once I reprimed the fuel filter and got the truck level all was good. I had 12 gallons in the main tank and 27 in the auxiliary tank. My question is this normal? Should my fuel filter have drained back to the tank? Just don't want this to happen again.

Certainly not normal. It doesn't matter how you park it, it should never do that. I suspect there's a hard code stored that your SG can't access.

Not sure if your Duramax has a glow plug relay or not, but I replaced mine in my 7.3 twice. Both times it would turn over quite some time, then might start eventually. On mine I popped the lid off and found 12 volts on the main feed and no volts on the other side. Relay shot. Should have 12 volts on both sides when warming up the glow plugs to start.

A friends truck did the same for a couple of months. The primer pump at the fuel filter was losing prime. There is a rebuild kit for it or the whole assembly for just a little more that includes a new filter. He bought the assembly which fixed his problem.

Paul Clancy wrote:Lift pump.There is no lift pump on an 08 Dmax.My LBZ did the same thing last year. No codes or anything. The only CEL was a bad glow plug but it was on for months before the CNS. I checked for filter pressure and it was fine. No air or anything.About 3 hours later it started and has ran perfect ever since. Oh and the hours reset for some weird reason. Really weird.

Had a no start on my '08 GMC Duramax LMM today.

Halmfamily
Explorer
Jun 06, 2018
RCMAN46 wrote:
To the OP

When you first pumped the fuel filter did you open the bleed screw until you got diesel fuel.

Then after diesel fuel at bleed screw close the screw and pump until it becomes very hard.

I suspect and agree you need to overhaul the filter head. Very common problem with the Duramax especially if it has a lot of miles on it. Merchant Auto also has a spacer for the filter head which makes changing the filter a little easier.

I did as you said but would not start when I tried. Once I rolled it back level that's when my son started the truck. It sat level for several minutes before he started it. I did ask him if he did anything different and he stated he left the ignition in the on position for about a minute and it started.
RCMAN46
Explorer
Jun 06, 2018
To the OP

When you first pumped the fuel filter did you open the bleed screw until you got diesel fuel.

Then after diesel fuel at bleed screw close the screw and pump until it becomes very hard.

I suspect and agree you need to overhaul the filter head. Very common problem with the Duramax especially if it has a lot of miles on it. Merchant Auto also has a spacer for the filter head which makes changing the filter a little easier.
larry_barnhart
Explorer
Jun 06, 2018
killerbee wrote:
You experienced a slow gravity drain off the filter head, by virtue of the nose up grade. Sometimes you will have to re-prime 2 or 3 times to evacuate the last bit of vapor in the filter. Happens to all gen dmax trucks. The CP3 just won't pull air enough to prime. I would not worry about it, it will probably never happen again. But FYI, if you park it with high hood temps (like we get in Phoenix or after a hard pull), the diesel in the filter will vaporize, causing the exact same issue. You can try popping the hood up to prevent that.

Killerbee please private message me. chevman
Turtle_n_Peeps
Explorer
Jun 06, 2018
Halmfamily wrote:
S Davis wrote:
Halmfamily wrote:
OP here, truck has now started fine last night and this morning several times. Truck is also running perfect. Just hoping it lost prime and won't happen again . That is for all the advice. I will change out the fuel filter when we get home, it's only four months old, and check all seals as well

If I were you I would get the rebuild for the filter head, it will only get worse. When it happened to mine it started sucking so much air the truck would lose prime and the truck would not run.

Just ordered the kit and an aluminum bleed screw from Amazon. Thanks for the advice.

Waste of time IMHO even though air leaks are common. Air leaks don't fix themselves. If you had an air leak your son could crank until the batteries were flat and it would not start. That didn't happen because he got it started.

That said it's never a bad idea to replace your plastic bleed with an aluminum one but again that wasn't your problem.

I'm curious if your hours reset. It's a common computer glitch with these trucks. You might want to check the hours on your truck.
killerbee
Explorer
Jun 06, 2018
You experienced a slow gravity drain off the filter head, by virtue of the nose up grade. Sometimes you will have to re-prime 2 or 3 times to evacuate the last bit of vapor in the filter. Happens to all gen dmax trucks. The CP3 just won't pull air enough to prime. I would not worry about it, it will probably never happen again. But FYI, if you park it with high hood temps (like we get in Phoenix or after a hard pull), the diesel in the filter will vaporize, causing the exact same issue. You can try popping the hood up to prevent that.
Halmfamily
Explorer
Jun 06, 2018
S Davis wrote:
Halmfamily wrote:
OP here, truck has now started fine last night and this morning several times. Truck is also running perfect. Just hoping it lost prime and won't happen again . That is for all the advice. I will change out the fuel filter when we get home, it's only four months old, and check all seals as well

If I were you I would get the rebuild for the filter head, it will only get worse. When it happened to mine it started sucking so much air the truck would lose prime and the truck would not run.

Just ordered the kit and an aluminum bleed screw from Amazon. Thanks for the advice.
S_Davis
Explorer
Jun 06, 2018
Halmfamily wrote:
OP here, truck has now started fine last night and this morning several times. Truck is also running perfect. Just hoping it lost prime and won't happen again . That is for all the advice. I will change out the fuel filter when we get home, it's only four months old, and check all seals as well

If I were you I would get the rebuild for the filter head, it will only get worse. When it happened to mine it started sucking so much air the truck would lose prime and the truck would not run.
Halmfamily
Explorer
Jun 06, 2018
OP here, truck has now started fine last night and this morning several times. Truck is also running perfect. Just hoping it lost prime and won't happen again . That is for all the advice. I will change out the fuel filter when we get home, it's only four months old, and check all seals as well
lazydays
Explorer
Jun 06, 2018
Sounds like you lost fuel pressure. If it keeps happening you'll need to rebuild your Primer Pump assembly. Just hope its not your CP3 pump going bad.
RVhiker
Explorer
Jun 06, 2018
I had a no-start on my 2008 Duramax 2500HD and the problem was the fuel pump relay. I swapped in the air conditioner relay (the same part number relay as the fuel pump relay), and the truck immediately started. And has kept starting - and now I carry a spare relay.