I finally got my truck running after nearly a week. I figured I'd put up some lessons learned to help out others with the same issues.

Problem was the truck died while driving home. When I got it home, I found fuel in the valley and the fuel bowl was empty. I changed the fuel filter, and was able to get it running, but for only a few minutes, then it died again. The fuel bowl was empty again. I figured the fuel pump was shot.

I changed the fuel pump and replaced all the rubber hoses. I also pulled out the schrader valve out and replaced it with a fuel pressure gauge. The fuel system was completed drained at this point, so I filled the fuel bowl with diesel kleen. It still took a long time to get the truck started - about 15 attempts. In the middle of all this, the tach stopped working. I replaced the CPS. Still no tach. It turns out that if you run your batteries down, the tach won't work, not sure why. I had the truck jumped to my Bronco, but one of the clamps stopped making a good connection. I figured this out after replacing the CPS (good thing too because the old one was melted on the end).

The truck ran for about 5 minutes, then died again. This time I was able to watch the fuel pressure hold steady at about 50#, then die off. The fuel bowl was empty again. I checked the fuel tank selector and could hear it working, and the fuel gauge would change when I switched tanks. I disconnected the fuel supply to the fuel pump and disconnected the fuel line from the selector valve and blew it out with compressed air. I got some junk out, but not much. I then blew air through the selector valve to each tank. On the back tank, I heard a pretty loud "something" go through the lines and then make a "thud" in the tank. Nothing from the front tank.

I was finally able to get the truck started - it took even longer this time (from filling the supply hard line). It ran for about ten minutes on the front tank. When I switched to the rear tank, it ran for about 3-4 minutes, then started dying. The fuel pressure dropped to about 20#. I switched to the front tank again, fuel pressure came back, and started running right again.

So now it runs, runs good, but I still need to drop the rear tank and clean it out. I have seen a lot of fuel pump and related posts lately, so I hope this helps some of you guys out.

 

Good catch on the blockage. Glad you got it running! I'd be interested to see what you find in the tank when you clean it??

 

Thanks Cuda. It was a very frustrating project. It seemed liked I was throwing money at symptoms for a while, but at least there was something wrong with the things that I replaced. The most important thing that I wanted to get across was that you can lose the tach signal when your batteries are low, and start thinking that the CPS is bad when that may not be the case. I guess the lesson I really learned was that when you have enough new parts installed and you still have the original problem, you have to think outside the box.