Hey, y'all. I'm posting this here since it's a diesel-related question but not something specific to my particular truck (1993 F-250 7.3 liter IDI).

I've had this truck about a month and have been doing a lot of work to correct problems that the PO left unaddressed. One of these issues is the the forward diesel tank had a locking cap on it for which the PO did not have a key. I don't have the full info on how long this tank has been unused, but the time period definitely measures in years.

Correcting this has not been a priority, as the truck had other issues, but I picked up a replacement fuel cap and one day when I was near a locksmith shop I had them remove the locking fuel cap. I have not put any diesel in this tank, but I did switch to the forward tank with the key on/engine off and the fuel gauge read EMPTY.

At the time of sale, when questioned about the locking fuel cap, the PO claimed he had once switched to the forward tank with the engine running, and that the truck continued running for a minute or two. I am uncertain how reliable that statement is.

My question, of course, is what the diesel gurus here recommend be done before returning this tank to use?

 

not an expert, but I would use it through a tank or so then change your fuel filters at a minumum.

Worked on a tractor once that had to have tank replaced, we found a matching tank on a non-running (with trees growing in it) similar model.

Water tested the tank, dried it out, fueled it up and used the tractor--
it still had enough stuff to plug up the filter on the second tank.
DID N'T leak though.

Oh and add an additive, case there's fungus.


my 2cents

Chris

 

Thanks for the reply, Chris. While you were writing that, I was outside dropping the tank, though. It's off now, and here's why:

Earlier today I drove to the Post Office (about a mile or so). Truck ran like usual. When I came back out, it would not start. Cranked fine, batteries seemed strong, but it would not fire off. Fuel gauge for the rear tank showed one-quarter full.

Remembering what I'd read hear about the pickup tubes in the fuel tanks failing and causing an apparent out-of-fuel condition at 1/4 tank, I had the truck towed about another mile to the gas station. I put $20 worth of diesel in it and it started right up. So, it would seem that my truck has another of the typical problems of these 7.3 IDI's (I've already replaced the Autolite glow plugs with Motorcraft, and I'm working through an E4OD transmission shudder now).

So, since I now consider my rear tank undependable, I decided to go ahead and drop the front tank and have it checked over. Hopefully I can get it remounted and into service quickly. Then I can tackle the issue with the pickup tube on the rear one.

Thanks for the reply anyway. I was beginning to think no one was going to answer my question.

 

Update: The midship tank is now mounted back under the truck, with everything reconnected.

The fuel pickup 'foot' was in pieces in the bottom of the tank, and there was 5 gallons of diesel in it - roughly 1/4 tank. I put a 3.5 inch piece of Gates 5/16 fuel injector line on the end of the pickup, with a v-notch cut in the end and 4x 1/8 holes drilled through the sides near the end just for good measure. Then I put 5 gallons of fresh diesel in it.

After driving back home from getting the fuel (using the other tank) I parked the truck in the driveway and hit the tank switch. I expected the engine to falter a bit, figuring there was likely air in the fuel lines to the tank I'd just reinstalled. However, it never missed a lick. The only indication that I had switched was that the fuel gauge dropped to E. (Checked the reading again with the sending unit disconnected and tank reads waaay above Full.)

So, my question is - did it actually switch tanks? Or is it just showing the input from the front sending unit (which is apparently dead) but still pulling fuel from the rear tank? I know I can drive far enough to burn up the 5 gallons I put in and see if it dies at that point, but is there any other way to tell?

 

Well, no replies, but it's been the Fourth of July holiday week...

Meanwhile, it appears from fuel usage that while the gauge switches to the front tank (dead sending unit) when I flip the fuel selector, the pump is still pulling from the rear tank. O'Reilly has a replacement fuel selector for under $100. Any recommendations or cautions about doing this switch-out?

 

Can the tank selector (the part mounted on the frame rail) be removed and cleaned, with any hope of it starting to work again? Or am I better off to simply purchase a new one?

Anyone?

 

At the cost I personnally would install a new one. From what I have checked it's less than $100 part

Chris

 

I would tend to agree with you, but I have to confess I'm an inveterate tinkerer, so I'll have to attempt to fix the existing selector before I commit any money to the job.

 

if it's like the one for F150 gas engine...just get a new one...Had to have mine in the F150 changed ('91) about three years ago..mechanic charged more for the trying to clean up and get to work (three hours shop time) than the install. (30 minutes to replace)Needless to say, I didn't pay for his clean-up efforts.Chris