bought a 2011 duramax last week and I'm having some problems. the truck won't start unless i give her a shot of either. i know i know don't use either! but once i give her a shot of it she starts right up and runs great but if i shut it off she won't start back up. I've replaced the injection pump with a brand new one from gm and still the same problem.i look and my scanner and it isn't building the pressure that the computer is commanding but as soon as i give her a shot of either she starts and has no problem holding the pressure commanded.
I've talked to a few people and they say that she needs injectors.
iv checked for code and i don't have any except for a glow plug. now before i did the injection pump i had a low rail pressure code but i don't seem to have it after i replaced the pump.
any ideas??? any and all help would be appreciated!

 

you need to do a fuel return rate test. this would tell you where to go from there

 

sounds like injectors are having issues, if they are just letting fuel pass through it can not build enough pressure while cranking. i am not up on duramax fuel systems to much, is there an orifice in the return to keep pressure up? sorry thats all i have to offer man good luck and let us know??

 

there a recall call on the rail about pressure or something i cant remember off the top of my head i got it the mail the other day. look in to that see if that helps.

 

Pull each injector return line one at a time and crank. If there is more then just a small spit coming from an injector, its returning too much. Usually when an injector is bad it will be a steady stream of fuel coming from the top of the injector fuel return.

 

My brother bought one brand new and went through 4 rails! 4 of them under warranty in 6 months and finally traded it off knowing gm wouldn't fix it

Don't know if there is an aftermarket rail that doesn't suck but if there is even its not your problem start saving for one. It ran awesome and got good milage but the factory rails and factory replacements are the worst rails ever made period. End of discussion .

 

I have never heard of the fuel rails ever needing to be replaced on the duramax. May want to recheck that one

 

Nope. Some check valve or something on the rail kept going out. And they says there was nothing that should have been causing it. (but they worked at a stealership) and may have been waiting for warranty to run out to hit him with a bill

But yep went through a rail like clockwork about every 8k miles

 

What year truck was this?

 

Bought brand new it was a 13 model