LB7: 2003 LB7 Hard start when warm then stalling/no start
- Thread starter nh_duramax
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the rise in frp occurred when I pressed on the throttle as I was going down the road. I assumed this was supposed to happen. Am I wrong?
the climb in pressure is gradual. if I am getting air in the line, why would the prime button stay solid? I apologize for what may seem like simple questions but I am new to diesels.
Your symptoms really sound like injectors, not a fuel pressure regulator or air in the lines. The climb in rail pressure with throttle is because your engine is opening up the pressure regulator more and more, and that is enough to overcome whatever is losing fuel (injectors, leak, ??).
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I appreciate the input. I think I will give the injectors a shot. Albeit an expensive shot. Many thx,
You could have not seated the top part of the gasket and getting air that what happen to me a couple of weeks ago. Had to take the filter off and redo it again. Has not stalled since.
looks like I found it. A friend of mine borrow a home made air pressure adapter with a regulater. hooked it up to my compressor and the fuel tank via a modified fuel tank cap. pressurized the system and found a fuel line coming off the tank spewing fuel like crazy. the line is a rusted mess so I am going to replace it and any others that look like they will leak in the future. I will update this post after I fix it to let you know the results. many thx.
Install a section of clear tubing on the outlet side of the filter housing. If air is the culprit you will see air bubbles in the fuel. IMHO air is not your problem. Your symptoms sound like high injector return rates. I would perform a fuel return test.
You can also put a long hose on the inlet side of the filter housing and run it in a bucket of fuel. That will eliminate the rest of the truck from the equation.
Good luck
You can also put a long hose on the inlet side of the filter housing and run it in a bucket of fuel. That will eliminate the rest of the truck from the equation.
Good luck
I worked on this for a day and a half this weekend. so here is the update. the leak was on the supply line at the quick disconnect joint between the supply line directly from the tank and the long supply line going to the top of the motor. I ended up having to puchase the Long fuel line and return line kit from the dealer and then the supply line coming directly off the tank because the rotted piece was corroded into the quick disconnect end of the line coming off the tank. Maybe I could have cut both ends at the leaky joint but puchased new OEM lines and spent about $600 for everything. And gues what it works great. Starts every time. Cranks for about 2 seconds and starts. I watch the FRP as it cranks and as soon as it gets above 1500 psi it starts right up. Performance is back to normal and it starts hot, cold, immediately after shutting off, or letting it set. Thank you everyone for the advice. It was a real bugger getting the OEM lines in but the key for the long run was to un-bolt the ABS unit from the frame and then I could thread the lines through to the back.