Is my tank selector going out again!?

[chaselee]

Backstory: When I bought my 96 CCSB powerstroke 2 years ago it was bone stock everything. Shortly after getting it, it started running really bad. I took it down to my buddy (local diesel performance shop) and he told me that I had 0 fuel pressure. They dropped both tanks, cleaned 22 years of rust and crap out of the tanks, blew the lines and all was well.

Not too long after that I started modding. Bigger injectors, bigger turbo, Irate E-fuel, and Super duty intercooler with Irate piping, Hydra tunes etc..
About 2 weeks ago I started hearing my fuel pump getting loud, not only getting loud, but also making a surging noise, but I was busy and had no choice but to drive the thing until I got a day off.

Thursday I took it in to him to have it looked over and once again he told me that my pressure really low, oh and I had burned up my fuel pump. I was excited as you can imagine. he said I had some restriction again so he backblew the lines and rigged up a SD fuel pump to get me by til the new parts came in. Upon his recommendation I ordered both new tanks, new sending units, new in tank plastic pickup screen thingys, and a new Walbro 255 fuel pump from Irate.

Today my front tank was getting low so I switch to my rear...no change in fuel level, so I semi-panick thinking that somehow, someway, just maybe I hadn't filled the rear tank. Keep in mind, when I stop for fuel, I ALWAYS fill both tanks..run the front first until almost empty, then switch to the rear. Once the rear gets to 1/4 repeat the process.

Swing into the fuel station, fill the front tank, move to the rear and it only takes 6 gallons, which was super puzzling to me as I never partially fill my tanks. fire the truck up and switch back to the front tank and it reads full like it should.

Ive already replaced the tank switching valve on the frame rail once, maybe about a year ago, but amongst all my other problems it seems to be acting up again, as it seems to be only reading the front tank.

Sorry for the book, but I figured a little history was necessary in this case. Any words of wisdom from the OBS Gods is appreciated. Ive already spent $800 on parts this week, I sure don't want to have to buy another $300 switching valve. Thanks!!

 

[JCart]

Hey Chaselee, no god here, but some suggestions and thoughts...

Might have fine bits of Keerap in the tank switch valve, that is preventing it from switching completely over to rear tank.

Regarding tank size, might not be for everyone but I like extended range. For the rear you can get an F26E, exact same dimensions as stock only 7” deeper = 38 gallons, can hang the spare under there too. Did this on my 97 CCSB and worked awesome. On my sig Tan truck this summer installed a poly 132 litre (32 gallons) tank from I think SD CCSB (was hard to tell as I picked it from a frame only truck). Used the fuel pick up that came with it, did the hutch mod and had to swap plug wires. Also had to change the front mount a little, used a combo of stock and SD tank straps, works excellent.
Cheers,
j

 

[chaselee]

Hey Chaselee, no god here, but some suggestions and thoughts...

Might have fine bits of Keerap in the tank switch valve, that is preventing it from switching completely over to rear tank.

Regarding tank size, might not be for everyone but I like extended range. For the rear you can get an F26E, exact same dimensions as stock only 7” deeper = 38 gallons, can hang the spare under there too. Did this on my 97 CCSB and worked awesome. On my sig Tan truck this summer installed a poly 132 litre (32 gallons) tank from I think SD CCSB (was hard to tell as I picked it from a frame only truck). Used the fuel pick up that came with it, did the hutch mod and had to swap plug wires. Also had to change the front mount a little, used a combo of stock and SD tank straps, works excellent.
Cheers,
j

Thanks for the info. I've already bought my tanks, just waiting on them to arrive. Same as factory, just poly instead of steel.

 

[JCart]

Cool cool... poly works for sure, on mine I pulled out the inner fuel hose and plumbed in a larger air vent line. Hooked vent line into the steel elbow, fills way faster now and no fuel spills on box side.
j

 

[chaselee]

Alright boys I've really got some weird sh!t going on!! So for the past 2 days I've been under the assumption that I'm just running off of my front tank and my selector valve is toast, because Everytime I switch to my rear tank the guage never changes knowing full well that I topped off the rear tank just a couple days ago. So this. On the way home from work my "front" tank gets down to about 1/4 tank, I stop to fill it up, and it's full...slap freaking full!! Put the nozzle in the rear tank and it takes almost 12 gallons! Does anyone have any idea WTF is going on!?

 

[Gnathv]

Sounds like selector valve is stuck. Pulling from rear tank and returning to front tank. Probably pieces of old pick up causing it. You can blow air pressure through switching valve from output side back to tanks, it may clear. There are valves on eBay for $60 that several people have used and had good results.

 

[Bugman]

I'd take the valve off and clean it along with checking the wiring to the tanks senders. Sounds like part of it is switching and part isn't. If it was pulling from the rear and returning to the front you would have a pretty good diesel leak once the front overfilled.

 

[chaselee]

I just tried to blow back into each tank. Got a small amount of gurgling from the front tank, but nothing from the rear. I called around and the cheapest I could find a selector valve locally was $400 and it wasn't even motorcraft, it was standard. So I went on Amazon and ordered 2 of them for $65 each. Now I'll have a spare. Only hope now is that my valve will continue to let fuel trough for another week til we can replace the tanks, senders and selector valve. Wish me luck!