VP44 temp while running
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From: Tenn.
[QUOTE=XLR8R;1119423]
Clunk - will the VP44 allow fuel to pass through it back to the tank if the engine isn't running?
QUOTE]
Ooops, a revolting development! I just went outside to check the overflow (fuel return) rate on the free 25 second starter bump and only about a half a cup of fuel came out of the inlet line to the cheapo fuel cooler (return line back to the fuel tank) and the lift pump showed 15.5 psi. I guess the motor has to be running to let fuel in or out or through the IP because I get nearly 2 qts./minute return with the engine idling.
Clunk - will the VP44 allow fuel to pass through it back to the tank if the engine isn't running?
QUOTE]
Ooops, a revolting development! I just went outside to check the overflow (fuel return) rate on the free 25 second starter bump and only about a half a cup of fuel came out of the inlet line to the cheapo fuel cooler (return line back to the fuel tank) and the lift pump showed 15.5 psi. I guess the motor has to be running to let fuel in or out or through the IP because I get nearly 2 qts./minute return with the engine idling.
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From: Texas/Oklahoma Border
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From: Pattonville, Texas
If the engine is not running, but the lift pump is (key on), does the fuel flow through the VP44 back to the tank? The internal cam/rotary vane of the IP just provide the high pressure, so what happens, flow-path-wise, to the low-pressure fuel from the lift pump?
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From: Pattonville, Texas
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From: Pattonville, Texas
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From: Texas/Oklahoma Border
On piece of data I remember from previous testing done is that fuel temps at the tank, while operating, are remakably consistant.... in the 100*F to 110*F range ...... even under extreme OAT's of 0*F to 100*F. This included my personal data (using a FASS w/o a fuel heater).... and others using RASP's.
RJ
RJ
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From: Pattonville, Texas
On piece of data I remember from previous testing done is that fuel temps at the tank, while operating, are remakably consistant.... in the 100*F to 110*F range ...... even under extreme OAT's of 0*F to 100*F. This included my personal data (using a FASS w/o a fuel heater).... and others using RASP's.
RJ
RJ
We're seeing temps on the IPs approach 200*F
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From: The Plywood state FL
My understanding is that the seals inside the VP44s fail more often than the electronics due to heat soak... any techs who know care to weigh in?
Roland - I don't think airflow is significant in alleviating the heat soak. My testing shows that IP temps are much more sensitive to the fuel temperature and rate of flow than the ambient airflow or temperature, which is why the heat soak is so rough on them - no coolant (fuel) is being circulated.
WadeCool - the cummins isn't going to be washing the oil off the cylinders when it's warm outside!
Clunk - will the VP44 allow fuel to pass through it back to the tank if the engine isn't running?
smokindog - I've seen CP3 temps as high as 175*F, and the VP44 run even hotter; those temps are outside the design envelope of any non-hardened electronics, and on the ragged edge of the seal materials commonly used by OEMs.
Roland - I don't think airflow is significant in alleviating the heat soak. My testing shows that IP temps are much more sensitive to the fuel temperature and rate of flow than the ambient airflow or temperature, which is why the heat soak is so rough on them - no coolant (fuel) is being circulated.
WadeCool - the cummins isn't going to be washing the oil off the cylinders when it's warm outside!
Clunk - will the VP44 allow fuel to pass through it back to the tank if the engine isn't running?
smokindog - I've seen CP3 temps as high as 175*F, and the VP44 run even hotter; those temps are outside the design envelope of any non-hardened electronics, and on the ragged edge of the seal materials commonly used by OEMs.
Its the other way around the heat soak kills the eletronics thats why you always get the injection pump timing faliure code most of the time the truck will start cold but once it gets to temp and you shut it down it wont restart.
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Will the death of LP cause the IP temp to be higher. I pulled a fema camper from Baton Rouge to Arkansas, and it was really hot to the touch. Will it be better to let it idle for a while after pulling so at least fuel is going thru the IP to cool it?
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From: Pattonville, Texas
We already know that heat soak is the problem, electronics and otherwise...
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From: The Plywood state FL
Yes because the LP flows more fuel then needed so that the excess fuel carries heat away from the IP. Thats one reason why DC has us perform fuel flow test rather then being so concerned with actual pressure. Pump volume is most important on both fuel systems for cooling. Even still i would still want to have a fuel pressure gauge inside the truck to give early warning signs of a failing LP.
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From: The Plywood state FL
All i was trying to say is that i believe heat soak has more effect on electronics of the IP not so much the seals and internals. Id have to say 90% of the IP's ive replaced and ive replaced alot of them have failed eletronicly not failed mechaniclly.