Deuce keeps getting air in fuel system

[Floridianson]

As I posted I am thinking the crack pressure is lower than 33/38 . Most of the time the TM's are a good reference but I do not hold them as Gospel.

Edit OK checked the crack pressure with the orifice blocked off. This needle and seat has no rubber and really is cheap but it does the job. The crack pressure is around 18 psi. to be noticed and 60psi. is fully opened.

 

[ivbeenrokd]

Okay, aside from cracks, and pressures, and valves, there was an interesting turn of events on the truck today.

I took it to the Knoxville Christmas Parade and it ran excellent, best it's run in years. Then, on the way home it started missing and died on the interstate. I started it back, drove another 1/4 mile and it died again. I started it back, it idled fine, drove a few hundred feet, and it died again. I left the pump running, cracked the bleeder screw, and no air, just fuel. I cracked the fuel cap and heard a decent bit of air. I thought maybe the vent line is clogged so I left the cap half on so it wouldn't hold vacuum. Started it up, drove an 1/8 mile and it died again. I limped on another few miles (because we weren't that far from our warehouse) but it got progressively worse. Finally at about an 1/8 mile out we walked and got a Tundra and pulled it to the warehouse. The pump is running and pumping fuel but not near as much fuel as usual is coming out of the bleeder valve on top of the secondary filters when I crack it.

This problem came on all of the sudden, it was running great and then boom, not running good.

Jeepsinker, I know what you're going to say: It's that piece of junk fuel pump! LOL. However, be creative, can you think of anything else? I've already ordered the parker but it's not here yet.

Is it possible the vent line is clogged puting more strain on the pump and has weakened/damaged the pump? Is there a different possibility?

Thanks,
John

 

[Jeepsinker]

Either the vent is plugged and you are pulling a vacuum on the tank until it won't pull fuel anymore, or your primary fuel filter is plugged, or, like I told you, that pump wasn't enough to begin with, and now it is failing. You may have also sucked a piece of trash up against the pump intake inside the line.

Mostly just sounds like the primary filter is plugged though. That is common.

 

[ivbeenrokd]

Either the vent is plugged and you are pulling a vacuum on the tank until it won't pull fuel anymore, or your primary fuel filter is plugged, or, like I told you, that pump wasn't enough to begin with, and now it is failing. You may have also sucked a piece of trash up against the pump intake inside the line.

Mostly just sounds like the primary filter is plugged though. That is common.

My thought on the filters was that it would likely be a little slow: Loss of power getting slowly worse. Can it actually cause a problem this fast?

 

[Jeepsinker]

Absolutely.

It runs for a bit, then dies, then restarts and moves a bit, then dies.. that tells me fuel is getting by the filters, but once you put a load on the motor it uses fuel faster than the fuel can get past the filters, then it dies. Let it sit with the lift pump running, and it catches back up and will run. Almost certainly filters.

 

[rustystud]

Your pump might also be the cause. I have had a gasoline pump fail after trying to pump diesel fuel. I don't know why either. The pump was brand new. It ran like gang busters for about 1/2 an hour then it just stopped pumping. It was still running just no fuel coming out. I don't know if it has anything to do with the "viscosity" of diesel fuel vrs. gasoline or what. Just something to check. Of course it could just be bad filters !

 

[Floridianson]

As said do all your filters. Then if you look over the TM's the one that is called troubleshooting the 465 there you will find the quickest way to find engine problems. After the filter change I believe it moves on to checking fuel pressures and on down the line till the problem is found. Even the TM say it is the quickest way to find problems as jumping around you could miss it.

 

[Blackbear]

I had a similar issue, it was the initial or what I call the third filter underneath, not the two up top. I would be curious that the pump would go out that fast. That filter element is a really short so all the junk drops, now that your pumping it might be full of tank trash etc.
Cheers,

 

[Floridianson]

No worries but Primary the one under secondary and final is closest to firewall.

 

[Blackbear]

Roger that.

 

[Floridianson]

We have the Grammar Police, The Attitude Police, The TM's Police plus parts name and NSN# Police. Will let you off with just a warning this time so smoke the tires and drive it like you stole it.

 

[ivbeenrokd]

I replaced all of the filters this morning (call them whatever you want, LOL), still have the problem. We'll see what happens when I get the pump.

 

[Jeepsinker]

Pull your in line pump out and see if the inlet has trash in it. While you have it off, blow the fuel line between it and the tank out.

 

[frank8003]

in tank pump police

We have the Grammar Police, The Attitude Police, The TM's Police plus parts name and NSN# Police. Will let you off with just a warning this time so smoke the tires and drive it like you stole it.

Don't forget the "proper parts police" and the "picture police".
Put a proper "immersed in fuel" in-tank pump hose on it with the new pump.
Assure the tank fill port gasket seals on re-installation.

 

[Blackbear]

Great pics, love that varnished look.

 

[frank8003]

My thought on the filters was that it would likely be a little slow: Loss of power getting slowly worse. Can it actually cause a problem this fast?

Faster than Yes

 

[frank8003]

Great pics, love that varnished look.

Pretty sure that pump was in the tank 1969 until 2012. I did not know there was an in-tank pump or that it was DEAD until soon after I got the truck I changed all the filters and it would not start at all. It was running on the main pump only until I broke into the system to change the filters.
I had created a new to me 13,000 lb. lawn ornament.

 

[Blackbear]

I had the same issue, runs great now, but still taking 3 solid cranks to fire it up, after it sits a few days. If it's warm it fires right up.r

 

[daytonatrbo]

Don't forget the "proper parts police" and the "picture police".
Put a proper "immersed in fuel" in-tank pump hose on it with the new pump.
Assure the tank fill port gasket seals on re-installation.

Holy smokes, my fuse was a 2A slow blow. I felt bad replacing it with a 4A slow blow. 20A is nuts, unless its SUPER fast acting.

 

[ivbeenrokd]

Well, here's the update. Pump arrived this morning (super fast shipping). I pulled the old inline pump and had a line made to take it's place. I pulled the tank and pump assembly and found the pickup had a bunch of junk in it so I think ultimately that was the real problem. I went ahead and installed the new in-tank pump, fired it up, and backed it out. I didn't have time to wind the winch back in and do a road test but I will do that tomorrow. My final conclusion is that the inline pump design works fine but I would do a bottom mount sump kit to do it right if I ever did it again. I would also try to keep the inline pump as close to the pickup as possible. Thanks again for all the help!

John