loss of fuel pressure

[dripley]

drove home yesterday, 350 miles with no issues, everything normal. i knew i had run the tank pretty low but should have had a couple of gallons left. went to my son's house this am and backed down his driveway. while ideling the engine appearred to run out of gas. with a low tank and steep down hill grade i could not see it being something else. we got back later with 5 gallons of fuel, put it in the truck and bumped the starter. fuel pump ran but no fuel pressure. i figured the slope was enough that the fuel wasnot deep enough to get to the pmp. went back and got 5 more, no change. went back and got 5 more no change. we pulled the truck out of the drive way and got it pointed down hill, still no fuel pressure. the pump is running but picking up no fuel. neither of the 2 filters on the AD had much fuel in them and i drained some from the FWS and found more dirt particles than i expected to see. i removed the FWS and sitting on top of the filter was a bug about twice as big as a house fly, how that got there is still beyond me. the second filter had some fuel in it but not much. it seems that every thing is pointing to a clogged filter, but every thing was working fine and then the engine shot down like it ran out of fuel. the other thing i noticed while checking the filters is an opening just to the left of the fuel supply and return lines that as i remember had a plug in it and now is open. i stuck my finger over it and tried to prime the pump with no success. there is another plug on top of this part of the pump and that plug is in place. one of these is for a pressure gauge, but i dont know what the other is for.if it is not a clogged filter is there something i am over looking? have not bought spare filters yet so i cant try that until i get some(not smart i know, but feel free to take your best shot).

[Mopar1973Man]

Ok the water/fuel seperator is a suction filter so if the drain is open by chance during the pump running it will suck air through the drain so be sure you drain is closed tight. I would open the line at the VP44 and allow the pump to prime to there into a bucket. If you have to use a blow gun and a rag and put a bit of air pressure to the fuel tank to help prime it. But typically AD pumps have been good about dry priming...It might be time to contact AD and see what they got to say too.

[jlwelding]

A few years ago I bought my first AD100 and it would not prime with dry filters. Probably along the same thing Mopar is saying. I had to fill both filters and had line disconected at vp and when it primed it sprayed fuel everywhere. Also when I change filters it will syphon fuel from tank when there is no air in the line, so kinda makes sence that air could be the problem.

[RJC2]

Let us know what happened. I am wondering about this one myself.

[dripley]

when i checked the filters they were both tight and the drain on the fws was tight but i did loosen it with my fingers. i could not find any thing on AD's site about the plug at the fuel outlet and return, but it appears to be missing. i could feel no suction on it while trying to prime it, but i dont think it should be open.when i installed the pump it had no problem pulling fuel from the tank with dry filters. i had to do it 2or 3 times before i had it set up the way i wanted it, but the filters were full the last couple of times. i guess i will try again tomorrow and hope i can find a suction leak somewhere. i dont think i can find any filters before monday.

[RJC2]

I don't know how closely related the AD165II and the AD100I is, but I just had a discussion about the port for the pressure sending unit with Eric at Vulcan yesterday. It was the one on the top of the base plate that is used for it on the 100 model. There weren't any open ports on it anywhere. I know many of these units are much alike, (like the AD100 & AD150) only different motor speed or gearing, you probably already know all of this but I thought it might help.

[thracing]

if you are sucking air its going too be somewhere between the tank and the pump,as for the filters it will make no diff if they are full or dry the pump will prime its selfdos the pump sound like its running hard or free?free its air, hard its a pluged filter if you are finding bugs and dirt in your fuel system chances are she ran low and pluged its self solid

[dripley]

i am thinking clogged because of all the dirt that came out of the fws, but how the bug got on top of the fws is a mystery. it is about 3/8" long and a 1/4" wide. it was completely intact. i did not have any tools with me last night but am headed that way shorltly with some.the port at the outlet and return is still amystery. i could not find anything about it last night, but it does appear to be missing a plug of whatever sort was in there to begin with. i will let yall know what i find.

[jshmohr]

I know I have a Fass not a AD but same pricipals. About a year ago I had the same problem and I fought it for a couple of days, finally I took a full 5 gallon fuel can and took the supply line off at the fuel tank and sumerged it into the fuel can and then tried to prime the pump and bingo. Found out the stock fuel pickup was sucking air inside the tank. So then had to order the draw straw, installed that and primed right up but had allready junked the VP in the process:banghead: but fixed the pickup problem, good luck:thumb1:

[dripley]

got to the truck and still no pressure even with it facing down hill. took off both filters and the filter screen. the screen was clean. the filters were near half full,so i filled them up, reinstalled them and bingo i have pressure. loosened some injector lines and she is running again. i dont rember having to fill them when i installed it, but maybe i did. hopefully this never happens again but if is does and i put 15 gallons in the tank i think i will save a quart for the filters. appreciate yalls helpit turns out the plug in the other port was still in place. did not have good enough light to se that yeaterday, i reckon.

[RJC2]

When I did my install the directions said to fill the primary filter before installing it. I just filled both to be sure and all went well. I am glad your up and running. Amazing how the bug got in there.

[dripley]

i put 15 gallons in yesterday and just filled up and put 20 gallons more in. just ran it out of fuel. have not done that in 5 or more years. just goes to show that the in tank pump replacement kit that came with the ADII works very well.the bug still amazes me. i wish i had taken a picture of it. completely intact and sitting on top of the fws. it must have gotten in the filter before i installed it. there just no way for that thing to have been sucked in there with the fuel.i am:hyper::hyper:.