Hey folks. My friend has a 1985 F150 that recently broke down on the side of the road and I'm hoping someone can point me in the right direction regarding the problem.

It seems fuel related. After sitting or after the fuel pumps are primed it'll turn over, run for a few seconds, then die. I can hear the pump inside the tank running as well as the pump inline. We replaced the secondary fuel filter, but cannot find the primary. We also replaced the fuel pressure regulator.

I'm not very familiar with older fords, and because it's pre-ODB1 era we can't pull codes. I'd really like to help this fella out as he has kids, but am unsure what exactly to replace. Was told if the pumps (both electric) cut on, then they're fine.

It's a fuel-injected 302, but am unsure if it's tuned port or throttle body injected. Doubt it's an injector issue, but I'm out of ideas on this point.

Any ideas? The primary fuel filter bugs me. I couldn't find it. The truck has only been recently put back on the road after sitting. Thanks.

Edit: After skimming through all 38 pages, I've come across a few diagrams and ideas of where to look:

http://i608.photobucket.com/albums/t...ordfuelres.jpg
http://i608.photobucket.com/albums/t...FIfuel-sel.gif

He said his fuel gauge works intermittently. I'm guessing the fuel reservoir is clogged? I'm looking at that diagram and it doesn't appear to be an electrical issue. Else it could be that primary filter I just can't seem to locate. Going to try and bypass the reservoir tomorrow if I still can't seem to find the primary. (The secondary was a cylindrical insert).

 

The main filter is just in front of the high pressure fuel pump both located on the driver side frame rail under drivers seat.

There is also a 2nd filter inside the fuel reservoir / tank selector shown in the picture that you found. You unscrew the bottom part of the reservoir to replace that filter. This part is also on the frame rail next to the front tank.

I would disconnect the fuel lines (one at a time) from the selector and run them into a jar to see if they are actually pumping fuel. You will have to turn the key on and off several times as the fuel pumps only work for 2 or 3 seconds if the engine does not start. (Or bypass the fuel pump relay to keep the pumps on for the test).

 

I appreciate the reply, klricks. Was hoping you would chime in towards this dilemma. In addition to the aforementioned replacements, we replaced both fuel pumps. I must say, the quickest way to learn a vehicle is to break and fix things. Sadly, still no progress.

We took the supply after the reservoir off and nothing will come out until after we got the high-pressure pump sucking from a gas container. We've still yet to locate the metal canister filter, but I'll look for it in the morning. My friend's dad was under the truck most of the time so I never had a chance to look, but thought it would have been before the reservoir.

Is it possible the reservoir is clogged? We've replaced the filter inside. If so, since I understand it's a $184 part, and he's only using one tank; can simply I bypass it with 3/8" fittings? I'll check out the secondary filter beforehand. Thanks again.

 

I know my '86 has a fuel filter installed within about 12" of the high pressure fuel pump. It looks to be factory installed with the quick connects etc. Last time I replaced it I had no problem getting one from an auto parts store.
Here is a photo:
http://i608.photobucket.com/albums/t...PFP_filter.jpg

However looking at my '86 Ford service manual, it does not show this filter in any of the diagrams and does not mention it at all the fuel filter section. The reservoir filter is mentioned. So it may be something that is not on all builds?

If I understand you correctly you said in your last post that you replaced 2 fuel pumps.... so that would mean that you replaced the HP fuel pump and one of the in-tank pumps.
If you disconnected the 3/8" line coming from the tank at the back of the reservoir and run that into a jar or gas can it should be pumping fuel from the tank into your container. If not then there is an electrical problem at the dash tank select switch or in the wiring in-between the switch and the tank pump.
Another possibility is that the fuel line is blocked between the reservoir and tank.

Yes the reservoir/tank selector can be plugged up or not working correctly. Depending on whats wrong there could be several symptoms. Like return fuel from the engine being returned to the wrong tank etc.

If you want to bypass the reservoir and use only one tank then you would need to connect the 3/8" supply line to the HP pump and the corresponding 5/16" return lines would need to be connected together as well. I would add a generic fuel filter in place of the reservoir on the supply line only. You would also need to make sure the tank that you will use is always selected on the dash switch. Maybe bypass that with a jumper wire so it does not get switched off accidentally.

In my case I replaced the whole tank selector/reservoir with an aftermarket motor driven tank selector + added fuel filters and got both tanks working. It was annoying to have to fill up every 150 -200 miles when only 1 tank was working.
http://i608.photobucket.com/albums/t...TankSelect.jpg
.

 

just a thought on your problem.you said the truck has been sitting for awhile.whats the quality of the gas in the tanks.todays gas is crap compared to the gas using the mtbe additive.gas could be turpintine by now.