'95 12V Fuel Problem, "Towing" P-Pump Replacement Recommendations?
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07-21-2022, 03:02 PM
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'95 12V Fuel Problem, "Towing" P-Pump Replacement Recommendations?
Hi all, I've spent the last two years (off and on) chasing my fueling problems and I am finally asking for help before I spend the money on a new P-Pump. If you all agree it is time to replace the pump, I am looking for recommendations on build specifications for a towing type scenario. Vehicle is a 1995 Dodge Ram 3500 4X4 automatic dually with the 5.9L 12V Cummins turbo diesel with 60K miles. It is technically a 24ft "Serro Scotty RV" weighing roughly 12,000 lbs at all times so I figure under typical operation it is "towing", let alone when we actually tow with the RV (often) typically weighing a total of ~19,000lbs.
Summary of problem and repairs so far
Truck randomly looses power - cannot build boost, throttle is unresponsive, entire truck shakes when this occurs. Event lasts a couple of seconds then goes away briefly for a couple of seconds then starts over again. This tends to happen 3+ hours into a trip. If we turn the truck off and sit for a while (30min+) we can get back on the road driving normally. I've replaced all fuel lines with new rubber hoses, replaced the fuel filter, lift pump, adjustable overflow valve and fuel pressure gauge. Fuel pressure does not drop when this is happening. It seems, based on what I've read, a plunger on the P-Pump may be sticking and my best bet is to replace the injector pump. Thoughts?
Fuel Issues Background - Long Read, Sorry!Bold part is still occurring.
On a road trip in 2020 (towing), the truck randomly lost power - lost/couldn't build boost, throttle was unresponsive - with a very shaky feel to whole truck. It lasted a couple of seconds then went away, truck accelerated building boost for a couple of seconds and then it happened again. This continued off and on for a bit until we pulled over and searched the internet for this problem. It looked like our lift pump was failing us. Ended up that the rear fuel filter was loose and letting in air (Serro added a second fuel filter pre-lift pump along with tank selecting valves). New fuel filters and over a thousand miles later it happens again. Swapped in an AirDog fuel system including supply line and thought the problem was fixed.
On the next long drive, it happened again. Decided to go back to stock with all new fuel lines (supply and return), new lift pump, new stock fuel filter, and remove the rear (pre-lift-pump) fuel filter. Added a fuel pressure gauge to watch what happens to fuel pressure when it happens again.
Next long road trip a year ago (not towing), it happens again 4+ hours into the drive. Noticed the fuel pressure on average seemed low. Pinched the return line to increase pressure and continued onward. Do not have many any more issues on the trip out. Ordered an adjustable overflow valve and replaced and adjusted before drive home.
Drive home is during a heat wave. Continue to have problems despite adjusted fuel pressure. Ended up waiting until the middle of the night when the temperatures dropped and continued the rest of the drive home without incident.
So it seems to be heat related and still fuel related. I believe a plunger on the P-Pump is sticking when things warm up and causing issues.
I appreciate the help or advice!
Summary of problem and repairs so far
Truck randomly looses power - cannot build boost, throttle is unresponsive, entire truck shakes when this occurs. Event lasts a couple of seconds then goes away briefly for a couple of seconds then starts over again. This tends to happen 3+ hours into a trip. If we turn the truck off and sit for a while (30min+) we can get back on the road driving normally. I've replaced all fuel lines with new rubber hoses, replaced the fuel filter, lift pump, adjustable overflow valve and fuel pressure gauge. Fuel pressure does not drop when this is happening. It seems, based on what I've read, a plunger on the P-Pump may be sticking and my best bet is to replace the injector pump. Thoughts?
Fuel Issues Background - Long Read, Sorry!Bold part is still occurring.
On a road trip in 2020 (towing), the truck randomly lost power - lost/couldn't build boost, throttle was unresponsive - with a very shaky feel to whole truck. It lasted a couple of seconds then went away, truck accelerated building boost for a couple of seconds and then it happened again. This continued off and on for a bit until we pulled over and searched the internet for this problem. It looked like our lift pump was failing us. Ended up that the rear fuel filter was loose and letting in air (Serro added a second fuel filter pre-lift pump along with tank selecting valves). New fuel filters and over a thousand miles later it happens again. Swapped in an AirDog fuel system including supply line and thought the problem was fixed.
On the next long drive, it happened again. Decided to go back to stock with all new fuel lines (supply and return), new lift pump, new stock fuel filter, and remove the rear (pre-lift-pump) fuel filter. Added a fuel pressure gauge to watch what happens to fuel pressure when it happens again.
Next long road trip a year ago (not towing), it happens again 4+ hours into the drive. Noticed the fuel pressure on average seemed low. Pinched the return line to increase pressure and continued onward. Do not have many any more issues on the trip out. Ordered an adjustable overflow valve and replaced and adjusted before drive home.
Drive home is during a heat wave. Continue to have problems despite adjusted fuel pressure. Ended up waiting until the middle of the night when the temperatures dropped and continued the rest of the drive home without incident.
So it seems to be heat related and still fuel related. I believe a plunger on the P-Pump is sticking when things warm up and causing issues.
I appreciate the help or advice!
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