babyjskustomauto
Registered User
hey guys this forum is great for information. usually a search will get me everything i need but im having trouble with something a little more specific so i thought id start a new thread. first a little history: last year i bought an 88 f super duty flatbed tow truck, it would barely start and when it would fire it blew smoke missed etc. compression test reveals good compression in all cylinders, truck has x74k on it (x being an unknown variable, dont have enough odometer slots) so figuring at best case scenario 176k i put a standard motor products rebuild injection pump as well as 8 rebuilt injectors plus a carter p4070 electric lift pump and motorcraft glow plugs on a pushbutton. fixed all starting and driving issues and was good for a while. I got stuck with it once before about 2 weeks ago and when i jumped out of the truck i couldnt hear the lift pump running, i knocked on it and it started back up and i was back down the road. I replaced the unit and put a metal inline filter before it because i think thats what killed it.
now yesterday as im driving i get like a "dead pedal." as im hitting the gas the druck is just decelerating and eventually stalls when it comes to a stop. this time i can still here the lift pump running, but symptomatically its exactly like last time when the pump quit. after sitting in the middle of the road for a few minutes i crank it for about a solid 30 seconds and it fires, drives me another mile or two then the same thing and im stuck again. then it happened one more time in front of my house, after resterting it the third time i pull it in my driveway.
when i replaced the defective p4070 i replaced it with a p4389 because its supposed to be identical to the p4070 except rated for diesel on paper (in case thats the reason my first p4070 failed.) I have it mounted down on the frame rail passenger side engine compartment front of truck. I have a piece of 3/8 soft hose going from the original mechanical lift pump steel line, into a 3/8 metal inline filter, into the pump inlet. To me im picturing a scenario where the lift pump is unable to supply to injection pump the volume of fuel it needs so the truck eventually starves for fuel and stalls. by letting it sit for a few minutes with the pump running it refills the system and the truck will start and run for a bit till it runs out of fuel again. Im also picturing a scenario where the injection pump is overheating and shutting down, and restarting after a few minutes of cooling down.
My plan is to relocate the pump closer to the fuel tank with a more formidable pre filter (maybe a spin on mounted on a head) and a pressure gauge so i can monitor pressure in the supply line. If my lingering fear of IP problems comes to fruition, however, im gonna be stuck in a 30ft truck with lots of lift fuel pressure and no IP. Rereading what i just wrote, i dont even know what specific question im asking, i think im just telling you guys where im at and seeing what you guys would do. most people on here describing IP failures are getting smoke etc, this is not the case for me my truck runs gret up until dead pedal and stalls, once it restarts it runs good again till it dead pedals and stalls again. i got it into my driveway, im afraid to pull it back out.
now yesterday as im driving i get like a "dead pedal." as im hitting the gas the druck is just decelerating and eventually stalls when it comes to a stop. this time i can still here the lift pump running, but symptomatically its exactly like last time when the pump quit. after sitting in the middle of the road for a few minutes i crank it for about a solid 30 seconds and it fires, drives me another mile or two then the same thing and im stuck again. then it happened one more time in front of my house, after resterting it the third time i pull it in my driveway.
when i replaced the defective p4070 i replaced it with a p4389 because its supposed to be identical to the p4070 except rated for diesel on paper (in case thats the reason my first p4070 failed.) I have it mounted down on the frame rail passenger side engine compartment front of truck. I have a piece of 3/8 soft hose going from the original mechanical lift pump steel line, into a 3/8 metal inline filter, into the pump inlet. To me im picturing a scenario where the lift pump is unable to supply to injection pump the volume of fuel it needs so the truck eventually starves for fuel and stalls. by letting it sit for a few minutes with the pump running it refills the system and the truck will start and run for a bit till it runs out of fuel again. Im also picturing a scenario where the injection pump is overheating and shutting down, and restarting after a few minutes of cooling down.
My plan is to relocate the pump closer to the fuel tank with a more formidable pre filter (maybe a spin on mounted on a head) and a pressure gauge so i can monitor pressure in the supply line. If my lingering fear of IP problems comes to fruition, however, im gonna be stuck in a 30ft truck with lots of lift fuel pressure and no IP. Rereading what i just wrote, i dont even know what specific question im asking, i think im just telling you guys where im at and seeing what you guys would do. most people on here describing IP failures are getting smoke etc, this is not the case for me my truck runs gret up until dead pedal and stalls, once it restarts it runs good again till it dead pedals and stalls again. i got it into my driveway, im afraid to pull it back out.
