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Discussion Starter #1
Hi ! New to the duramax life. Bought a 2003 LB7 bone stock last october. Has now 80k miles. I began to have starting issues with it. Long crank times when cold (4-5 seconds). When it is warmed Up, if I shut it down and crank it back immediatly, it will fire right Up like brand new. If I let it sit for 5 minutes or more (fill the tank, grocery, etc.) it Will crank forever or won't even start. I got the fprv replaced for the PPE race plug because it was leaking pressure, did the fuel return rates test and got 90-95 ml for 15 sec of cranking, looks the specs. The last Time it didn't start, I waited 3 hours and when I came back it fired right back. No smoke, runs like New. Looks like from 5 minutes to 2 hours of sitting is the critical "no start" Time.

Need your help to fix that Beauty !
 

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Exact symptoms i had when my FPRV went bad. Are you sure you installed it correctly?


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Have you attempted pumping the plunger on the fuel filter head? Did it make any difference? Somewhere the truck isn’t getting fuel and it seems like you already checked the high pressure side so im guessing its the low pressure side


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Discussion Starter #5
Yes the plunger is Hard or get Hard after 3-5 pumps. When I replaced the fuel Filter, There were bubbles at the bottom of the water separator where the wires are. Could a small leak There cause this ?
 

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Yes I replaced it, and IT is when I put the New Filter back on and thighten the water separator that the bubbles showed Up. I was not shure at that Time if it was fuel from the full fuel Filter that dripped There or a leak. But thinking back now if There were bubbles IT is definitly a small leak
 

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Yes I replaced it, and IT is when I put the New Filter back on and thighten the water separator that the bubbles showed Up. I was not shure at that Time if it was fuel from the full fuel Filter that dripped There or a leak. But thinking back now if There were bubbles IT is definitly a small leak
Ya and you will not notice a leak because the low pressure fuel side is actually under vacuum rather than pressure. So it will suck air, not spray fuel


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Discussion Starter #9
New updates. After replacing the fprv for the PPE race plug, Truck started to run into the same problem. The mechanic redid the fuel return test and was at 60ml now for 15 seconds and would not start back, was stuck in the shop. He replaced the fuel pressure regulator. I got it back two Days ago, has lot more Power and response from What I find. Yesterday, my girlfriend went to the store and was stock There, IT would not start back after 15 minutes of shopping. It took me another 15 minutes to get There. I primed the bulb to get it Hard (5-6 Times), crank it and bam fired right Up. Should I look for a rebuild kit for the fuel Filter housing ?

Thanks !
 

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Just buy a new housing. I hear the rebuilds are hit and miss.
 

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It doesn't have to be for the LB7 just need longer hoses to accommodate the bends. Most use the one for the lly or newer.
 

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New updates. After replacing the fprv for the PPE race plug, Truck started to run into the same problem. The mechanic redid the fuel return test and was at 60ml now for 15 seconds and would not start back, was stuck in the shop. He replaced the fuel pressure regulator. I got it back two Days ago, has lot more Power and response from What I find. Yesterday, my girlfriend went to the store and was stock There, IT would not start back after 15 minutes of shopping. It took me another 15 minutes to get There. I primed the bulb to get it Hard (5-6 Times), crank it and bam fired right Up. Should I look for a rebuild kit for the fuel Filter housing ?

Thanks !
A new housing complete with Filter and WIF will set you back about $100 at Rock. Best deal going.
 

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Discussion Starter #14
Just bought a seal rebuild kit here in a local parts shop, threw a New Filter in and a New water separator sensor and it fired right Up. Running at it's best since I own the Truck. With that done, looking for a bit more performance. Stock LB7 is asleep compared to my tuned 4th gen Cummins.

Thanks to all for the advices !
 
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