LB7: Started up then died. Now engine wont start anymore.

[Jeremy]

Went to start my 04 LB7 this morning to let it warm up before going to work. As I shut the door and walk away, the engine died. I tried to fire it back up but it just spins over and doesnt start. The truck has 144k, has about 3.5k on new injectors installed by dealer, fuel filter was replaced around the same time. Truck has about 3/4 tank. No check engine light.

I thought maybe the connector at the bottom of the fuel filter was loose, but I checked and it was good. Other then that I didnt have time to check for anything else because I had to go to work.

Can you guys help me with some ideas of what to check for when I get home? I am a newbie to the Duramax and diesels in general.

Thanks

 

[JoshH]

Did you try priming the fuel filter?

 

[Jeremy]

^^ was thinking about it but I didnt because I was in a panic to make it to work. If I prime the filter and it fires, pump could be bad then?

 

[LWATSON]

could be a leaking fuel filter head

 

[Bryce418]

There are a couple valves in the filter head that have sealing issues at times.

Just as fair warning if its an lb7 make sure your sitting down when you price one!

 

[LWATSON]

You can get a rebuild kit for $20.00

 

[Bryce418]

Rebuild kit doesn't have the valves in it.

Usually the valve flapper gets folded or gets some junk in it and doesn't need replacement.

 

[blk smoke lb7]

If it started and then stopped im betting its not the filter head im betting you have 1 or more injectors stuck open.Id bottle test and see if you have a ton of fuel returning to the tank.Its a free test and you can eliminate a couple things by doing the test.

I had this happen to me is why i say it.

You can tell which 1s are stuck by pulling the glow plugs and pull the inj fuses and have someone on each side of the truck watching the glow plug holes and someone to crank it over the stuck injectors will mist out the holes of the 1s that are stuck.mine were both rear cylinders.

 

[Blaine]

If it started and then stopped im betting its not the filter head im betting you have 1 or more injectors stuck open.Id bottle test and see if you have a ton of fuel returning to the tank.Its a free test and you can eliminate a couple things by doing the test.

I had this happen to me is why i say it.

You can tell which 1s are stuck by pulling the glow plugs and pull the inj fuses and have someone on each side of the truck watching the glow plug holes and someone to crank it over the stuck injectors will mist out the holes of the 1s that are stuck.mine were both rear cylinders.

The fuel filter head issue will cause it to stop after its been running, the problem is usually pronounced when your parked on a hill.

 

[jraymer]

My filter head is bad and my truck does the same thing, truck starts then dies, pump the pumper, then it fires and all is glorious. I park nose down in my driveway and it starts every time.

 

[Bryce418]

I have been using the LLY filter adapter on the lb7 trucks. It needs a pretty creative line routing and quite a bit more hose, but $200 vs $600 makes it easy in my book.

 

[Bryce418]

If it started and then stopped im betting its not the filter head im betting you have 1 or more injectors stuck open.Id bottle test and see if you have a ton of fuel returning to the tank.Its a free test and you can eliminate a couple things by doing the test.

I had this happen to me is why i say it.

You can tell which 1s are stuck by pulling the glow plugs and pull the inj fuses and have someone on each side of the truck watching the glow plug holes and someone to crank it over the stuck injectors will mist out the holes of the 1s that are stuck.mine were both rear cylinders.

Not to be an ass but that's putting the cart in front of the horse.

If the truck started and died ~15 seconds later the smart money is on loss of prime. Start with the easy stuff anyway, jumping straight to a return test with his symptoms strikes me as somewhere between huh and wtf.

 

[blk smoke lb7]

Not to be an ass but that's putting the cart in front of the horse.

If the truck started and died ~15 seconds later the smart money is on loss of prime. Start with the easy stuff anyway, jumping straight to a return test with his symptoms strikes me as somewhere between huh and wtf.

As i understand its more work but it doesnt cost anything.I would try somethiing free before throwing parts at something.

 

[Harbin_22]

As i understand its more work but it doesnt cost anything.I would try somethiing free before throwing parts at something.

Me too Scott. Makes way more sense. $200 for something that "might" not do jack or free test, hmmm no brainer

 

[Jeremy]

Thanks for all of the replies.

So I got home from work yesterday about 9 hrs later, and tried to start the truck. No difference...it would turn over but would not start. I tried to prime the filter by pumping some fuel in the filter but still no go (only did that once) So I would wait a few minutes and then try to fire it up again. <-- Did this about 3 or 4 times. Finally I left the key in the on position for about 2 or 3 minutes and when I came back, for the hell of it I tried to start the truck again... and it fired up!

After I got it to fire I let it idle for about 5 mins, then came back and shut it off. After shutting it off I tried to fire it up again and the engine started up no problem. About an hr later I actually did need to use the truck to pick up some stuff, so I drove to run errands and then later on in the night took it on a nice lil 100 mile round trip. The truck ran totally normal all night.

While I was waiting for replies, I was doing some searching here on the forums as well...reading other posts where people had the same problem with their LB7. There was a guy that mentioned he basically had the same problem I did. He had it towed to the dealer, and as soon as they backed it off the tow truck the truck fired up fine and he said its ran perfect since.

I'm glad the truck runs, but I'm a little concerned because there must be an issue somewhere for the truck to act like that. The last thing I want is for the truck to leave me stuck somewhere. One thing I do want to mention, is the truck was parked for about 4 days with no use. So yesterday was the first day I went to use it. Its almost like the truck was jealous I wasnt showing it daily love like I normally do. :rofl: I also filled it up with about $65 worth of diesel on the same day I left it parked. Maybe I got a bad batch of fuel? I normally daily the truck and have never had one small problem with it. I always pump 76, Shell, or Mobil and have avoided the cheap stuff from the no name gas stations.

 

[blk smoke lb7]

Thanks for all of the replies.

So I got home from work yesterday about 9 hrs later, and tried to start the truck. No difference...it would turn over but would not start. I tried to prime the filter by pumping some fuel in the filter but still no go (only did that once) So I would wait a few minutes and then try to fire it up again. <-- Did this about 3 or 4 times. Finally I left the key in the on position for about 2 or 3 minutes and when I came back, for the hell of it I tried to start the truck again... and it fired up!

After I got it to fire I let it idle for about 5 mins, then came back and shut it off. After shutting it off I tried to fire it up again and the engine started up no problem. About an hr later I actually did need to use the truck to pick up some stuff, so I drove to run errands and then later on in the night took it on a nice lil 100 mile round trip. The truck ran totally normal all night.

While I was waiting for replies, I was doing some searching here on the forums as well...reading other posts where people had the same problem with their LB7. There was a guy that mentioned he basically had the same problem I did. He had it towed to the dealer, and as soon as they backed it off the tow truck the truck fired up fine and he said its ran perfect since.

I'm glad the truck runs, but I'm a little concerned because there must be an issue somewhere for the truck to act like that. The last thing I want is for the truck to leave me stuck somewhere. One thing I do want to mention, is the truck was parked for about 4 days with no use. So yesterday was the first day I went to use it. Its almost like the truck was jealous I wasnt showing it daily love like I normally do. :rofl: I also filled it up with about $65 worth of diesel on the same day I left it parked. Maybe I got a bad batch of fuel? I normally daily the truck and have never had one small problem with it. I always pump 76, Shell, or Mobil and have avoided the cheap stuff from the no name gas stations.

Glad you got it going :thumb:

 

[Duramax One]

My first thought is that Duramaxes are very sensitive to power issues, so I would check and clean your terminals on the batteries. Also, how old are your batteries? The fact that it worked fine after leaving the key on for a few minutes could indicate a weak connection.

 

[JoshH]

As i understand its more work but it doesnt cost anything.I would try somethiing free before throwing parts at something.

Not to sound like a *****, but last time I checked, priming the fuel filter is free also. I've never seen injectors cause a start then die condition, but I have seen a loss of prime cause it a bunch of times. Every time I have seen it happen, I just pump the primer until the button gets firm, and the truck starts up and runs.

Jeremy, I'm glad you got your truck running. Only question I have is, when you primed it, did the silver priming button get firm and hard to press? If not, you may have have a leak on your filter head or WIF sensor, or you could have a problem with the primer seals or the one way valves in the filter head.

 

[Jeremy]

Not to sound like a *****, but last time I checked, priming the fuel filter is free also. I've never seen injectors cause a start then die condition, but I have seen a loss of prime cause it a bunch of times. Every time I have seen it happen, I just pump the primer until the button gets firm, and the truck starts up and runs.

Jeremy, I'm glad you got your truck running. Only question I have is, when you primed it, did the silver priming button get firm and hard to press? If not, you may have have a leak on your filter head or WIF sensor, or you could have a problem with the primer seals or the one way valves in the filter head.

Josh, the silver button got firm very quick, within 2 or 3 pumps.

 

[Jeremy]

Bumping this up again.

Truck has been fine until today. Went to start it this afternoon for the first time in about 12 hrs and it did the same thing. Fired up, idled for a few seconds and then died. Now it all does just crank over. I need to source this problem while its acting up so it doesnt fail on me when I need it