Hi there I am stumped with this crank no start. It began with hard start becoming progressively worse where it got to the point where it would not start anymore (friend of mine’s truck, he’d use ether which I frown upon, and it would start up fine except would have a plume of ash colored smoke upon startup and during acceleration). I replaced the CP3 pump per his request as he went by his friends from work’s word and it did not solve the issue. I replaced all the rubber hoses and resealed the filter tower. I performed the bottle test and did not produce any fuel. The code I have is P1093. I checked the voltage and ground at the connector to the FPR (at the jumper harness that is accessible) and did notice when I plugged it back in, the voltage dropped from 12v to 2.4 at the source voltage to the FPR. I looked at electrical schematic and there’s no fuse or relay in between. Is this an issue or is there something else I should be looking at? I’m fluent with diesels and electricals and never had a headache like this one and would like to help the old man to save him from dealership as they are unable to take his truck in for another 3-5 weeks.
LLY Crank/no start
- Thread starter Jstahl71
- Start date
replace the fuel line coming out of the filter with a clear one and look for air or bubbles. could be a cracked housing or leaking seals.
and the voltage at the FPR is a PWM signal so you won't get an accurate reading on a normal DVM. unplugging it will also force full pressure, so even if there was a fuse or relay blown or not working that wouldn't stop it from making pressure.
start with making sure you aren't getting any air in the fuel to the CP3
issues like this are a good reason to invest in a lift pump
and the voltage at the FPR is a PWM signal so you won't get an accurate reading on a normal DVM. unplugging it will also force full pressure, so even if there was a fuse or relay blown or not working that wouldn't stop it from making pressure.
start with making sure you aren't getting any air in the fuel to the CP3
issues like this are a good reason to invest in a lift pump
Are there socks in the pickup tube on the sender? When cranking with the clear hose on the output side, there’s just a small stream of fuel coming down the line like it’s restricted or no fuel at all in tank but I know there’s half tank of fuel as he filled it up prior to bringing it to our shop. Also when I prime the primer I am achieving 12 psi on the gauge at test port but just small stream of fuel coming out the outlet of the filter outlet port
Some additional info for you. https://oregonfuelinjection.com/ser...gnostics-repair/chevy-gmc-diesel-diagnostics/
I will give that a try tomorrow. I left for the day 2-1/2 hours ago. I appreciate the input!
I performed the bottle test, wouldn’t that reveal leaking injectors overall? I will try the test where you cap off the line to cp3 pump and see if it does not produce 12” vacuum
I have previously done that and found both the hoses to the filter housing cracked and leaking which is why I replaced them long ago.
That depends on what you are calling the bottle test. It sounds like you are referring to the test that is performed to check for a leaking FPRV on the end of the driver's side fuel rail. That test will not verify leaking injectors.
Is the fuel filter full? Sounds stupid but I've seen the primer bulb go hard and it was just air locked. I'd check for collapsed fuel lines also. Something from the fuel filter to the fuel tank isn't right.
When I disconnect hose and put in jug, how do I get the air out since air will be trapped in the hose?
I’m getting 15 psi on my gauge after priming it. I know what you mean as I’m already feeling stupid as I’ve been a diesel tech for a long time (Ford, cat, Cummins, but some experience with duramax)
Does it prime? does the button get hard to press and you get fuel through he bleeder. I have had to replace my fuel filter housing twice in 15 years.
Yes it does prime. I can see the fuel movement on both clear hoses. There’s a mist of air bubbles moving through on the inlet side of the filter.
I put fuel jug in and primed the hose to the jug by filling up manually with funnel until air was all out and has the same result. Had 7.1 mpa (1,029 psi).