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Replaced both pumps, now it idles rough

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Old 08-09-2004, 08:43 PM
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Originally posted by F. Flack
I also noticed the pressure goes up to (around) 10psi with the lift pump when I turn on the key, but drops back down to 0 as soon as the LP quits running (if I don't hit the starter).

Franklin
It drops back to 0 PSI because the pressure bleeds back into the tank through the return line.
Old 08-09-2004, 11:26 PM
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Haulin - Just as you indicated, for two days in a row the engine would miss after it was started and I was backing out of the garage. This was what triggered me to check the volume of fuel flow when I found the air in the fuel. I figure the source must be major for the FASS to not be able to remove all the air -- I also noticed the FASS motor sounded like it was straining to keep primed. Once the tank was full, the FASS was able to work properly and significantly quieter.

I haven't checked the banjo bolts, but will. When it first started, I thought it was bad fuel. However, I've put 790 gallons of fuel (plus Howes additive) through the tank since the VP/LP failure, with recurring problems -- using the new LP and the FASS. I won't rule out bad fuel, but would need more of an explanation to convince me.

I called DPP to get their ideas on the symptoms. He wants me to verify the FASS is working properly with an additional “isolated” test (they want me to make sure before pointing the finger elsewhere). He indicated they have found an issue with the pick-up assembly causing problems and wants to work with me to get it resolved. I’ll post again after I finish the testing and drop the tank to look inside (within the next two weeks if timing works out).

Thanks, Franklin
Old 08-09-2004, 11:51 PM
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Franklin I faught with that problem for months. When I knew that I had to do something about it was when installing the last engine I had trouble getting fuel to pickup. I cured it by going to the bottom feed, but I am sure it is not necessary to go that far. Makes me wonder if that is the real reason for the lift pump and vp44 problems on these trucks.
Old 08-10-2004, 06:03 PM
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I called Doug at ADT today and ordered their 1/2" stand pipe kit -- comes with all fittings and 1/2 fuel line needed to connect directly to the FASS ($75 includes shipping). When I spoke to Doug, he indicated he has had a "run" on these kits and needed to order more fittings. My first LP lasted 80k miles. The second one only 30k -- and I was told it was suppose to be better than the original equipment. After speaking to Brad at DPP and Doug, I agree that the pick-up assembly could be causing more issues than people realize.

I felt it was worth getting the complete kit instead of trying to find the individual components to build one myself (I.E. going bottom feed) -- I volunteer too much of my time for hunter education this time of year and don't have time to fabricate a skid plate to protect the port. I should be able to get the kit installed by the 23rd and will post what I find when I open up the tank.

Thanks, Franklin
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