Hello, my name is ...and I'm an idiot.

[Nessmuk]

The plugs and injectors and pump must work. Not ran fine on the other tank. The only other possibilities are insufficient supply volume or surely low compression. I doubt the latter and don't think the first is likely as I have great filtration now.

 

[jrsavoie]

Have you tried fresh fuel in the other tank yet?

You said it ran fine off that tank previously.

Have you jumpered the lift pump and run about 1/2 gallon of fuel out the drain T? I usually run about 1/2 gallon or more out, into a glass pickle jar. note the flow, let it sit about 20 minutes and look for water bubbles or crud.

Have you pulled your fuel filter to check it? All it takes is one bad bit of fuel to plug it up. If your other tank was cruddy, that could be an issue.

My son had a bunch of bad bio in his truck once - 2 tanks. It ran fine out the other tank and the first tank eventually cleaned itself out

Where is your fuel pressure gauge T'd in at?

I believe there might also be a last ditch screen at the IP. Might be worth checking.

You can also pull the return line and run it to a container to see if that makes a difference. These are cheap easy things that I usually do when I start diagnostics and quite often, my problem is solved before I get done

 

[consaka]

I could see 1 or maybe 2 injectors being worn and sticking shut, but not all of them at the same time.

If you are questioning fuel quality, I always say trust your instincts- drain it and replace it. You can save ot in jerry cans and add back in 50/50 once truck is running if you want. Or hook up a jerry can feeding the lift pump. Just remeber you have to cycle the engine enough to replace the old fuel with new when trying to start.

Where would I start?
Pull the glow plugs real quick (ok 2 arent quick so skip them 2) and crank it over. You should have a fuel mist from the 6 you do pull.

Then a quick bench test on the glowplugs that are already out.

5 minutes to do that and you know that you have proper fueling and working glows. Want to spend another 20 minutes and really know where the engine life stands, pull the all 8 glowplugs before "mist test" and then do a compression test.

Nothing beats a compression test to let you gauge the health of the engine. White smoke out the exhaust should be the same as the mist test though. If you have mist and or white smoke then you know you have fuel in the cylinder and your no start problem is likely more related to glow plugs, timing, cranking speed or compression issues.
I love troubleshooting. Can't wait to hear what he finds out.

 

[Nessmuk]

Thought I'd try pumping out the bad tank and trying fresh in both tanks. I have a compression gauge somewhere, packed away.
My gauges are pre and post filters, just post fuel pump and pre injection pump. If it keeps it up I'll check the inlet screen, but it's hard to get at.

 

[jrsavoie]

Thought I'd try pumping out the bad tank and trying fresh in both tanks. I have a compression gauge somewhere, packed away.
My gauges are pre and post filters, just post fuel pump and pre injection pump. If it keeps it up I'll check the inlet screen, but it's hard to get at.

I'd save that for last then - if it runs good on one tank. Filter and inlet screen should not be an issue - Has to be the fuel in the other tank or something else related

 

[dangerousdave]

Sooo many of those over the years, the memories get stuck at the door all trying to come through at the same time.

I'll have to ask the wife- She seems to remember each mistake I make with such accuracy...

I'm luck my wife forgets almost as much as me.

 

[Husker6.5]

Could the problem be your tank selector valve is not opening up completely when switched to the "bad" tank, so you are trying to draw through a barely cracked open valve port?

 

[deejaaa]

if you suspect the valve, it's best to remove and test it. use a spare battery or power supply.

 

[consaka]

Could the problem be your tank selector valve is not opening up completely when switched to the "bad" tank, so you are trying to draw through a barely cracked open valve port?

Hmm if that was the case then his supply pressure would start normal and go to zero. When the engine was running. In fact the effect would be similar to a clogged filter which is that the engine would start but have no power. Or would run and then stall if it was bad enough. Least that is how it goes with my tractor when it runs on a plugged collapsed filter.

 

[Nessmuk]

Drained the passenger tank and refilled with fresh fuel. Added the new Walbro pump and it runs. The tank valves work too. I had to put the pump up top, as it didn't have room without moving the tank valves again and I've cut up my expensive fuel line enough already.
The primary, driver's tank won't pull fuel. It is either a pinched fuel line, or a plugged up sock?
I'll drain it and drop it and take a look.

 

[consaka]

Drained the passenger tank and refilled with fresh fuel. Added the new Walbro pump and it runs. The tank valves work too. I had to put the pump up top, as it didn't have room without moving the tank valves again and I've cut up my expensive fuel line enough already.
The primary, driver's tank won't pull fuel. It is either a pinched fuel line, or a plugged up sock?
I'll drain it and drop it and take a look.

Well that is some good news. I have seen plugged socks before. They slowly get something built up on them that closes them off. Brushed them off with a solvent and flushed it good and worked like new.

 

[Nessmuk]

It runs on both tanks!
Dropped the driver's side tank and blasted the sock with brake cleaner. Back together and it runs fine.
Now on to other things, oil leaks and maybe low pressure.