Truck doesn't like to start

[Duramax81]

Here's the scoop. My 01 Is being a pain in the ass. A week ago she stopped starting. Out of no wherre I went out one morning and I'd crank, crank but no go. I found that the bleeder plug on top of the Fuel Filter housing was cracked. I replace the plug, and the truck would start, but only after priming the filter every time. Once I got her started she ran like a friggen top. Tones of power, lots of go, ran like new! I was advised by several people to replace the housing.

So I did so, and I also replaced the rubber hoses as they were starting to disintagrate. Took alot to get it running, but once it started it ran great, as it did before. I shut it off, and tried again. Took a little cranking to get it going, but it started. Wen't for a long drive (2hrs) to make sure that there was absolutely no air left in there.

Came out the next morning, and again took a bit to get started, but started. Drove to work no problem (45 mins). Got to work and shut it off. Just out of curiosity I went out to try and start it up. And NOPE!!! No fire! I checked for fuel at the fuel filter and nothing. I pumped and pumped, the primer and like 100 later I got some, but it drained away almost as fast! It took 3 people to start it to get it home. One pumping, one bleeding out the air, and one cranking. I haven't tried yet to get it going again, and I'm scared to find out, lol! Any advice would be great!!!

[lmholmes11]

When you changed the fuel filter housing, did you make sure the O-Ring came off with your old filter? Having two o-rings up in the housing will cause an air leak. Trust me, i've done it!

[Duramax81]

Of ya, totaly checked that. I've also made that mistake, lol!

[MacDR50]

I had some time during lunch so googled this problem. The concensus is that there is air still in the system or a leak that is allowing air into the suction side. I am assuming it would have to be a small leak not to impact the engines performance or one that closes under suction and then opens again when shut down and lets the fuel blleed back into the tank.

Here is one of the successful responses.

"Now, back to your problem, it sounds like you have air in the system. I would remove you fuel inlet line at the fuel filter ( the one with the arrow pointing in) then have someone blow compressed air in the fuel tank through the fuel filler. Use a rag to seal around the air blower the best you can. Do this until fuel comes out the hose you disconnected from the fuel filter. Reconnect the fuel line and remove the black air bleed screw from the fuel filter. Blow compressed air in the tank again until fuel comes out of the air bleed. Once you have fuel comming from the air bleed reinstall the black plastic plug and try the hand primer. With the air bleed closed it should get hard to push after about 10 to 20 pumps. If it does not then there is dirt inside the hand primer. Then try to start the truck while someone is blowing air in the fuel tank. The should force the rest of the air out of the system."

It came to my mind that if you plugged the fuel line at the pump then put compressed air on the lines it might make it easier to spot leaks. Kind of like finding a slow leak in a tire. The same would apply to the filter housing when you reconnected. Does anyone see a problem with this?

[JohnC]

Just be sure you keep the pressure in the tank very low, 1-2 psi ought to be nough. Doesn't take much to blow the tank apart. At 3 psi a 1 square foot section is carrying 432 pounds...

[abec]

yeah for duramax81's truck it was the injectors

[More Power]

An out of warranty injector replacement is not cheap. I'd want to find out why air is finding its way into the fuel filter between starts before spending the money on injectors. Ordinarily, some amount of air can migrate to the fuel filter over time, but not so much from one start to the next - unless there's an air leak or a low fuel problem.

Assuming there's not an "air" problem, checking the fuel rail pressures while cranking would be the next troubleshooting step I'd recommend. This would have pointed to either a high pressure pump problem or an injector(s) problem (with a high fuel return rate). In either case, a low fuel rail pressure would be the cause of a no-start. ;)

Jim

[abec]

yeah we tried that but at the end of it all the injectors were bad

[NutNbutGMC]

I hate it for anyone to have this problem of injector related failures.

These LB7s are disappointing to many from all that I (continue to) read here. It's thread after thread of problems with this engine. Been there too. Looks as if many are failing after less than 10 years of any mileagable service.

I can only envy the wrenchers here.

Good luck all.

[Hillbilly Jim]

My fingers are crossed, my 2001 built in Nov. of 2000 has not had any injector problems. I do use additive, biodiesel, double filter fuel and watch where I buy fuel. No small stations, never ever buy at deep discount or independent stations, never buy at stations and tanks built or installed more than ten years ago.
Wish me luck!

[madmatt]

I can only envy the wrenchers here.

Good luck all.

WHY?? GM screws us on diag and labor usually.

[hapaschold]

dont crank and operate purge pump at same time..... that could be adding more air into system

change the fuel filter again...

perhaps the fuel filter drain is letting air in.