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Discussion Starter · #1 ·
I have a 02, 2500 HD, Duramax engine that is losing prime. I have replace both rubber fuel lines coming from the fuel filter. I have replace the fuel filter twice, once with an after-market and now back to the OEM filter. I have replace the water sensor at the bottom of the fuel filter. I have been told that it might be my fuel pump which has a one-way flow valve that has become stuck allowing fuel to flow back to the tank. I'm out of ideas. If I let my truck set around 6 hrs or overnight, when I crank it, it runs around 20 seconds then shuts off and I have to re-prime it. The problems has gotten worst over time, I used to just park my truck with the engine facing downward on a slight grade and I would not lose prime, but now I'm losing prime everyday. Does someone have any advise?
 

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check that plastic bleeder screw on top. It could be cracked or the o-ring on it could be bad. The only other thing that it could be is a cracked filter housing. Are you sure both o-ring and gasket came off with the old filter? If it is the filter housing, your best bet would be to try and find one off e-bay or contact Eric Merchant at Merchant Automotive (gmdieseltech.com). They are pretty expensive from the dealer. (like $700 IIRC)
 

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i kinda have the same problem. I keep gettin air in my fuel system after long drives. Once you turn it off and try to start it wont start at all. I have to prime and bleed it like you ran it out of diesel. The pressure is good but theres alot of air bubbles in the diesel. WHATS THIS FROM? Please help. I have changed the plastic bleed screw, new filter and gasket even from the dealer twice!
 

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Sounds like you have the same problem....unfortunately it probably won't be cheap. Sounds like the filter head unit. Probably from your prime pump or if you ever had the dealer change the filter....could have had the "filter gorilla" put it on and crack the housing. How does your water in fuel sensor look? There could be a hairline crack in that causing your problem too and not dripping on the ground.
 

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Discussion Starter · #6 ·
Can you just bypass the stock filter, by installing a after-market filter system. The only thing about most of the after-market filters is that theire isn't a priming bulb. Is a priming bulb required?
 

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Yes, there is such a system that most people put post OEM filter and I have seen one that has a prime bulb. I would just make sure that it has a fuel heater if you live in a place that it get cold like below 0...but as far as warranty is concerned, I don't know what the dealer would say if you went in for injectors. Those systems could cost nearly as much as an OEM set-up would. They are nice though since it could be mounted where the second alternator would go.
 

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I took it into the dealer and they traced it down to a a fuel filter. I knew it wasnt tho cuz i just had it changed a month prior. It starts right up like it should after i change the filter. After some miles and driving for at least 30 mins it wont start up. Seems like longer you drive the harder it is to start if it doesnt fully cool down! The dealer looked at the fuel filter head unit and said it was fine. I havent checked the water sensor yet! Goin into the dealer tomorrow for injectors. Should i get a new water sensor?
 

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Do you have a wet spot on your frame? You could pick one up, but I don't know if it will help at all. It could be something associated with the injectors too.
 

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its hard to tell for a wet spot on the frame. I live in texas and the AC is ALWAYS on! lol! It starts and runs really good for a few weeks or so after each fuel filter change then wont even start at all til i prime it and bleed it. Hope the new injectors fix this problem!
 

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top front left of the engine is a valve with a gray cap that should be on it. this valve is where the fuel pressure is checked.It will cause the fuel system to bleed back down after shutting down for a time. be sure the cap is in place and seals. check it out
 

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so i got new injectors! injectors were BAD but was not the problem. I see the valve where u were talkin about but i dont see any cap on it! It starts decent during the day but in the morning it will barely start run for 1 second and completely die and wont start back up. I prime it and bleed it and then it will start. It does have air bubbles in the fuel line when i do bleed it. Could it be the vavle that is letting air into the fuel line?
 

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Its a type of shraider valve that will need the cap so that it does not suck air. normally the valve has pressure on the back side keeping it closed but after a long park time like overnight it will bleed off. It was my problem and a new cap which has to be bought with the valve will cure it. hope this helps.
 

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There is a primer pump on top of the filter head. You have to unscrew the bleeder screw and pump the pump until you get fuel out of the bleeder. Thats it.
 

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replaced Bleeder screw and O-Ring

My stock 03 Duramax ( Running on B100 ) started losing prime overnight but primed and fired right up in the morning. Performance was good with no indication of any problems until first crank of the day. Then One afternoon after a little pull with some weight on it back to the shop it did not want to re-start , even after multiple primes. Finally started and back to the house where I replaced the easiest and cheapest first ( The bleeder screw and O Ring ).
It started right back up.
Again this site has saved me down time and dollars.
:rockin
Thanks to all here who contribute.
regards and thanks
Tom

Okay Guys its a few days later now on Good Friday . The truck ran fine all day and re-started normally. The problem re-surfaced the day after I posted the above . The following morning, The truck would not start . Priming did not yield air in the system just fuel . I took it to the dealer and they told me it was either the CP3 or Regulator and to come pick it up because it has Biodiesel in it. They don't want to work on it. Unfortunately
I replaced the CP3 last year, the work was done by a non certified local garage by a non certified mechanic and I see allot of similar issues from guys that don't run Biodiesel.
Anyone have or know of an IP fail before 15K miles ??




Thanks
 

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Hey. I am having similar issues with mine. Let me know what ends up being the problem. So far I have done an o-ring replacement kit on the filter housing and a new filter and WIF sensor. And I am still having issue
 

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Moved to LLY-- 6 year old thread
 
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