pudder Posted December 9, 2008 Share Posted December 9, 2008 What are some of the common causes for a 1995 Mack CH to lose its fuel prime overnight? The truck has lots of hours on it (around 20,000+) and ever since the cold weather has hit, the truck will not start in the morning without priming the fuel pump.Could it be the primer unit, injector seals, return line grommets, or return line itself?Any common possible solutions to my problem would be greatly appreciated.MikeAnseeuw Brothers Ltd. Quote Link to comment https://www.bigmacktrucks.com/topic/6782-loss-of-fuel-prime-overnight/ Share on other sites More sharing options...
theakerstwo Posted December 9, 2008 Share Posted December 9, 2008 I would start with replaceing the fuel pressure regulator before putting a supply pump on it. I dont know if you can put a valve kit in that supply pump or not .The APE pump had replacement valve seats. glenn Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/6782-loss-of-fuel-prime-overnight/#findComment-26495 Share on other sites More sharing options...
LocomotiveBreath Posted December 9, 2008 Share Posted December 9, 2008 Sometimes you can find the culprit by putting a little air pressure on the fuel tank. If it's an external line or grommet it will usually show up pretty quickly. Just don't go overboard with the pressure, 10 to 20 psi should be plenty. This new ULSD is very dry and is causing a lot of hose and seal issues, especially on older equipment. Quote Link to comment https://www.bigmacktrucks.com/topic/6782-loss-of-fuel-prime-overnight/#findComment-26514 Share on other sites More sharing options...
fjh Posted December 9, 2008 Share Posted December 9, 2008 What are some of the common causes for a 1995 Mack CH to lose its fuel prime overnight? The truck has lots of hours on it (around 20,000+) and ever since the cold weather has hit, the truck will not start in the morning without priming the fuel pump.Could it be the primer unit, injector seals, return line grommets, or return line itself?Any common possible solutions to my problem would be greatly appreciated.MikeAnseeuw Brothers Ltd.Number one cause of fuel prime loss is any filters you have with plastic bowls on them on the primary side!Racor ect!If you have one of these on your unit by pass it and see if the problem goes away!Aside from that start at the begining check for loose fittings if the engine is vmac it has an orfice no leak off valve ,the primer Could be the problem but start with the cheap and easy stuff first!if it is a mechanical engine check the leak off valve, the spring may be broken. Quote Link to comment https://www.bigmacktrucks.com/topic/6782-loss-of-fuel-prime-overnight/#findComment-26554 Share on other sites More sharing options...
theakerstwo Posted December 9, 2008 Share Posted December 9, 2008 Number one cause of fuel prime loss is any filters you have with plastic bowls on them on the primary side!Racor ect!If you have one of these on your unit by pass it and see if the problem goes away!Aside from that start at the begining check for loose fittings if the engine is vmac it has an orfice no leak off valve ,the primer Could be the problem but start with the cheap and easy stuff first!if it is a mechanical engine check the leak off valve, the spring may be broken. I changed a 60S out on a IHC dump truck about 3 years ago out here at the house and the owner got a later usede engine and i put it in. Next morning afet it was do0ne i tried to start it and it had lost its prime. When i found it it was the plastic bowl on the single filter taken place of the two detriot filters leaking. I ask him what was wrong with his old engine. He said it will never start wgen i what it to. The engine cant be trusted so i got me a good one. I told him he still had the same proble and i repaired it. I said what are you going to do with that engine and he said will you haul it off for me . Sure. It was 11.1 DD but about 3 months later a girl need it for her dump truck . She was happy and i was happy. It runs 5 or 6 days a week ever since then. glenn Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/6782-loss-of-fuel-prime-overnight/#findComment-26581 Share on other sites More sharing options...
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