Thanks for all the great and patient info. There some other auto fora where nastiness is a virtue.

Now for the next question, my new '89 the light of my life got me reads "over full" on the front tank. I am assuming that this is the type of guage that reads high when "open", and thus I either have an open wire/connector or a bad sending unit.

1. how do I get to the tank? any access port like in cars? Please do not tell me that I have to drain the whole tank?
2. How much does a new sender cost. are there aftermarket at reasonable prices?
3. Is there an in-situ test that doe snot require disassembly?

 

Sounds like the level sensor is not hooked up, I knocked mine loose when I reinstalled the tank and got the same thing.

Easiest way to check it is the lay flat on the ground and have the light of your life drive it over you until you can see the front tank and the wires going into it, it will be on the driveshaft side.

A little harder would be to crawl under there and look.

The sender, I don't think can be bought without the whole pump assy.

 

my 87 does the same thing. im pretty sure mine is a ground but i cannot find where it grounds.all i found is 4 ground straps and i cleaned them.anyone know where it grounds too?it has 2 tanks

 

mine does as well but when almost empty it will read correctly thinkin its the sender

 

Replace the senders. I had to replace both of mine because of the same problems.

 

1. I see them on-line for $75 each. reasonable?
2. Do I have to drop the tanks to replace?

 

You will probably need to drop the tank(s) to replace the sending unit, and it has a wonderful metal locking ricng that is an top notch pain in the rear to get off, especially if your truck is a rust bucket. Your only other option (sarcastically speaking) would be to take the bed off which I came close to doing myself.

To add to this hunt for working gauges...my 88 F-250 doesnt read anything...no oil presure, fuel, temp, however...the volt meter works....I pulled the cluster out and tried to replace the clutster voltage regulator...but there wasn't one on the back side as in the cluster for my 84 F-150, anybody have a clue?...

 

You should drop the tank(s) at least a few inches on a jack. I took a chisel and hammer and tapped the ring counter clockwise to remove it. Going back together with it was a challenge since my o-ring unseated itself and didn't seal the tank. I had to drop it again to fix. Glad it's done, although it's not a difficult job if the tanks are nearly empty. I don't have to worry about rust here so it was relatively painless.