Long crank no start LB7

[paganone]

Hello guys I am new to Duramax motors and have an issue to resolve
The truck is an 02 LB7 and has p1093 and 1094 showing.

Using a Tech 2 i checked balance rates once I got it running on juice and had values from -2.3 to 2.7
When I commanded 160 MPA on the scanner it only made 64mpa.
Injector on times ranged from .34 to .49ms.
The rail pressure at KOEO is 1.6mpa
The filter is new

The truck doesn't smoke, just falls on its face and won't restart without help.
I pulled the return line off the back of the motor and cranked it twice for 15 seconds to see how much fuel it was returning. It was less than 75 ml
A contribution test showed nothing.
I'm leaning towards a regulator but really don't know for sure where to go next.
Can any of you offer some advice to a newbie?
thanks for your time.

 

[catman3126]

How much "actual" rail pressure does it make when cranking? needs to be a minimum of 14-1500 psi to enable injection to fire. if ti was idling and you asked for 160 and it only made 64mpa that's a problem, Possibly a cracked injector and you just haven't seen the fuel show up in the crank case or a CP3 pump went shithouse on you. Ive seen and LB7 that crapped out on the rod and was idling rough to to low pressure and never fired again after that.

 

[catman3126]

also need to check and see how much restriction the test fitting is showing on the low pressure/suction side of the fuel system. Ive seen a delco filter leave the rubber top hat looking seal up in the base and a napa filter will screw on and jam that up in the base and cause a restriction and pull 25 in-hg at idle.

 

[tsd_billy]

Get it comression tested Should be around 350 no more then 15 -20 psi less. And get a fuel leak dye test. If your dipstick glows after running it for a little then shit got real


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[tsd_billy]

also need to check and see how much restriction the test fitting is showing on the low pressure/suction side of the fuel system. Ive seen a delco filter leave the rubber top hat looking seal up in the base and a napa filter will screw on and jam that up in the base and cause a restriction and pull 25 in-hg at idle.

Happened to me before i had a heart attack until i found it


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