Pulled a 1987 out of a hole

[captain720]

Got some work done on the truck, new brake booster line, some new fuel lines. Valve cover gaskets are getting replaced, old ones leaked really bad and I do not want to rebuild my starter and dump oil right onto it. Gasket was so bad it shattered when I touched it. It was much much cleaner under the valve covers than I expected, no sludge at all and only a couple of very very tiny rust spots. Pretty good for a truck that sat axles deep in mud for 8 years.

 

[captain720]

I even found a sticker under all the grease and dirt. It seems the factory painters did not do a good job at all? Both valve covers have many many drips on the paint but judging by the stickers and what not it seems to be factory.

 

[IDIBRONCO]

It looks pretty normal under your valve covers. Surprisingly, these engines don't seem to build up much sludge as long as you keep up on the oil changes. The biggest cause of "sludge" that I've seen in when the valve guides go out on a 7.3.

 

[captain720]

Well I made it around the block! Than she died, got the valve covers on, got a minty new starter put in, replaced the fuel lines to the water separator and I prefilled the water separator to pump line and she fired and idled for about 10 minutes no problem than when I went around the block she ran fine but was down on power and when I parked it she died going into the parking spot. Havn't been able to trouble shoot that yet but it's always a good time. Have not been able to get to a computer for photo updates but wanted to share that.

 

[Big Bart]

Captain,

Many have had good results on sitting trucks by filling the fuel filter with atf. (I would replace the fuel filter at the same time.) Let the truck idle a few minutes to get the atf into the pump and injectors. Shut off the truck and let it sit overnight. Many have suggested that helped clear the injection system and the truck ran better.

Maybe just put on a new lift pump and rubber line to take that out of the equation. Up your reliability going forward.

Also 8 year old diesel should work but maybe time to replace it or dilute it with some fresh diesel. Your pushing the shelf life of #2. If any bio in it could be problematic.

 

[captain720]

Captain,

Many have had good results on sitting trucks by filling the fuel filter with atf. (I would replace the fuel filter at the same time.) Let the truck idle a few minutes to get the atf into the pump and injectors. Shut off the truck and let it sit overnight. Many have suggested that helped clear the injection system and the truck ran better.

Maybe just put on a new lift pump and rubber line to take that out of the equation. Up your reliability going forward.

Also 8 year old diesel should work but maybe time to replace it or dilute it with some fresh diesel. Your pushing the shelf life of #2. If any bio in it could be problematic.

Thanks for the thoughts! I have done all of that yes, the in tank fuel is about 50-50 old and new at this point. I did sea foam instead of ATF. Is ATF that much better?

 

[Big Bart]

ATF has detergents and such that seem to work well in these systems. Many a member has seen improvement so I am sold.

Back in the day a common practice on a diesel service was running a quart straight through on a German diesel vehicle. (Not sit overnight, just let it idle for 20 minutes and do it’s thing.)

Sea foam to me is more of a dissolver for gas related issues. Just my two cents on Sea Foam.

 

[IDIBRONCO]

I did sea foam instead of ATF. Is ATF that much better?

I'm not going to go into the use for Sea Foam discussion. All I can say is that you get more ATF for less money than you do with Sea Foam.

 

[captain720]

It absolutely will not under any circumstances pull fuel from a tank, I bypassed separator, pre filled all lines, it almost ran for a second and than just sucked straight air. I have no visible leaks. Is that tank switcher? Should I just rebuilt the whole fuel system? Is it a tank pickup? Both tanks are FULL almost overflowing. I am at a loss

 

[NeverHave-I-Ether]

Bad air leak in the system somewhere. I would completely redo the fuel system, it's 30+ years old at this point, the lines are rusted out on the inside anyways. I would run an entire new fuel system with hose and hose clamps. Rip out the old fuel lines from tank to pump.

Hosing lasts long time, cheap, doesn't rust, easy to install and modify. New fuel senders while your at it, then use 5/16 hose from the pickup/return to the fuel selector. #4 Hose clamps. I would also put in some valve shut off on the positive fuel line on the pump side of selector, comes in handy.

Never-Have-I-Ether

 

[Big Bart]

If both tanks are full it is not the tank pick up. The bottom part is plastic and comes off over time. Now it only runs to 1/8 of a tank and sucks air.

The fuel tank selector valves are notorious for failing at this age. Sometimes they stick in the middle of the travel so you get no fuel. Perhaps bypass to just one tank to test.

You could have a leak sucking air at the selector valve or the fuel lines from it to the tanks or the selector valve to the lift pump.

Your lift pump could also be bad. But if you have air in the lines hard to test it.(Is it sucking air due to a leak downstream, or is it not creating suction because it is not working.). But if the diaphragm in the pump is bad it could be your air leak.

Did you try to run a line from a gas can to the lift pump? Truck runs you have a air leak in your lines to the tanks or a bad fuel tank selector valve. Truck does not run you have a issue with the lift pump or perhaps the fuel filter.

Your challenge is it’s a néw truck to you, it sat 8 years, you do not know it’s history. So you have to start with a long list of what it could be, test those items on the list, and cross them off one at a time. At some point you find the issue. We have seen this movie many times here on Oilburners. Stay confident and know cooler heads prevail.

Sounds like you have a clear line so you can see air bubbles. Just know that even when it starts and the air starts to clear the truck is likely to start, run briefly, and quit. It may do this 3-6 times. Then idle erratically till the air purges out. Some have stated they had to bleed the injector lines before they could get theirs to start.

 

[captain720]

Truck runs mint off a can and the whole system has negative pressure in it when I let something go (pull a line anywhere and it sucks air in before letting fuel leak because the brand new lift pump sucked so hard it made a vacuum) so I think the tank switcher is the next thing to bypass for testing purposes. Rebuilding the whole system shouldn't be too bad, I've build them before just never with a tank switcher before. Too bad the tank switchers are mounted in such a weird spot sandwiched between tank and frame rail on these.

 

[Farmer Rock]

Truck runs mint off a can and the whole system has negative pressure in it when I let something go (pull a line anywhere and it sucks air in before letting fuel leak because the brand new lift pump sucked so hard it made a vacuum) so I think the tank switcher is the next thing to bypass for testing purposes. Rebuilding the whole system shouldn't be too bad, I've build them before just never with a tank switcher before. Too bad the tank switchers are mounted in such a weird spot sandwiched between tank and frame rail on these.

The fsv on single cab trucks is so fun to replace. You'll want to at least drop the mid tank skid plate. Amazon has replacement fsv's for under $60.
The rest of the low pressure fuel system is easy. Just be sure to replace whatever is left of the shower head pickups in the tanks..
Since your running a factory lift pump, you'll want to siphon the lines toward the engine, or pressurize the tank to help prime the lines when you get that far.


Rock

 

[captain720]

I finished the video about the valve covers if anyone wanted to see more of that.

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[Big Bart]

Truck runs mint off a can and the whole system has negative pressure in it when I let something go (pull a line anywhere and it sucks air in before letting fuel leak because the brand new lift pump sucked so hard it made a vacuum) so I think the tank switcher is the next thing to bypass for testing purposes. Rebuilding the whole system shouldn't be too bad, I've build them before just never with a tank switcher before. Too bad the tank switchers are mounted in such a weird spot sandwiched between tank and frame rail on these.

Good for you. Now you know its between the lift pump back And the tank.

To your point its not able to suck fuel like it’s clogged and creates a strong vacuum. Likely you fuel tank switch valve is stuck half way blocking off the fuel line. Perhaps one tank pick up is clogged.

You could try if it’s set to say the rear tank switch it to the front tank. Same issue then likely the selector valve is likely stuck between tanks. (but could be the line between the pump and selector valve is clogged.) Hit the switch a couple of times but end with the other tank. Same issue blow out the line from the lift pump to selector valve. (Cross that off the list.). By-pass the selector valve to one tank and test. Runs replace the selector switch.

Seems to be options out there.

1) I have one of these, just need to put it in. Hear it works but have not confirmed. Not sure if this will plug right in or require a little wiring.

https://www.amazon.com/6C3Z9189A-6C3Z-9189-F5TB-9F271-AA-Lucky-Seven/dp/B08B3VCZVG/ref=asc_df_B08B3VCZVG/?tag=hyprod-20&linkCode=df0&hvadid=463359003998&hvpos=&hvnetw=g&hvrand=4202665337129825117&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9031537&hvtargid=pla-967053999799&psc=1

2) Others have had luck with this one. Some put filters in front of the pump. You have to some wiring to make it work.

https://www.oreillyauto.com/detail/c/standard-ignition/fuel-delivery/fuel-pumps---tanks/fuel-tank-selector-valve/9ec07a2b1867/standard-ignition-5-terminal-fuel-tank-selector-valve/std0/fv5k/v/a/5318/automotive-truck-1986-ford-f-250?pos=1

3) This one is more and has mixed reviews. I have not heard of anyone on this site using this style.

https://www.amazon.com/Reservoir-Selector-Compatible-1989-1997-F1UZ-9B263-B/dp/B08LG1Q5FF/ref=asc_df_B08LG1Q5FF/?tag=hyprod-20&linkCode=df0&hvadid=475692271572&hvpos=&hvnetw=g&hvrand=4202665337129825117&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9031537&hvtargid=pla-1040227769166&psc=1

If needed you can pick your poison as they say.

Let us know what you come up with next and send some pics.