Got a 01 durmax in the shop for a crank no start, its got a new filter head, new cp3, new injectors within the last 10k miles and a new frp sensor, we have bled the system and nothing, the frp is desiring 42-45 mpa and the actual is stuck at 2 unless you unplug it which makes it around 180mpa, we’ve tried a known good ficm and that didnt fix it, ecm/ficm fuse is good, we tried the return test out of the main return line and it only had 50 milliliters which check it seeing as each bank say 12 mil each with cp3 using 20 roughly and the truck wont start at all, possibly ecm? It will run off old cosby juice but thats it, any info or thoughts?
01 Lb7 crank no start
- Thread starter Robertlawson6.6
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- lb7 crank no start
How many dmaxes have you worked on?
I pray the glow plugs were disconnected when you threw ether down it
Its hitting 180mpa with fpr disconnected and cranking?
Whats the cam and crank signal doing on scan data?
How did this issue come about that brought it to the shop? (Customer description and what theyve done)
Codes?
You got a scope? Probably going to need it
I pray the glow plugs were disconnected when you threw ether down it
Its hitting 180mpa with fpr disconnected and cranking?
Whats the cam and crank signal doing on scan data?
How did this issue come about that brought it to the shop? (Customer description and what theyve done)
Codes?
You got a scope? Probably going to need it
Moved to LB7 section.
Welcome
Got to fix that 2 mpa issue first. Even with a bad FICM, crank and cam sensors, it should still build pressure. I'm going to assume you unplugged the pressure sensor to get it to show 180 mpa. If so, that doesn't really tell you much
How are you priming the filter? Explain your process please
Got to fix that 2 mpa issue first. Even with a bad FICM, crank and cam sensors, it should still build pressure. I'm going to assume you unplugged the pressure sensor to get it to show 180 mpa. If so, that doesn't really tell you much
How are you priming the filter? Explain your process please
Worked on plenty of Durmax's, Its at a father in law’s shop and he is needing help with it, frp sensor defaults to 180 when unplugged which its in the hardline not the back of the cp3, it still wont start and second of all cam/crank is reading properly and the only code the truck has is a large air leak in the fuel system, customer said it just randomly shut off going down the road, no white smoke or nothing plus the customer put new filter housing on it and injectors less than 10k miles, im going to put pressure into the fuel system and see if i cant find a leak anywhere seeing as the hand primer looses prime after cranking.
Right, im thinking the frp sensor is reading 2 mpa due to it being air locked and sucking air when you crank it so it simply cant build rail pressure. I’ve by passed the filter housing and it still didnt start and with it hooked up i just use the hand primer, trucks primer gets softer and cranking on it which tell’s me its sucking it air from some where, im going to pressurize the system and see what i come up with!
Also with the whole glow plug ordeal, on my junky durmax 08 lmm its been started with 2-3 cans at once with break clean and never once had a issue with glow plugs, my stuff i dont care i’ll use whatevers but i dont use it on customers stuff, but yeah brake clean has never gave me a issue when it came down to starting my junk lol
Gotcha idk its got me a little stumped, im going to pressurize the system and see, i hate going over other peoples work lol
Crack a high pressure line at the rail, does it move fuel?
It sure sounds like the thing is air locked. It's also possible your hose is kinked off near the driver side of the engine, that's very common on these ancient trucks too. You can test this by putting air into the tank with a rag to add a little positive pressure or you can run a 1/2" ID hose to the nipple at the quick connect from a bucket.
It sure sounds like the thing is air locked. It's also possible your hose is kinked off near the driver side of the engine, that's very common on these ancient trucks too. You can test this by putting air into the tank with a rag to add a little positive pressure or you can run a 1/2" ID hose to the nipple at the quick connect from a bucket.
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It may be at one of the connections in the fuel lines from the tank. Definitely have to pressurize the fuel system to find it.