IP question

[IDIBRONCO]

Here's the short of it. Last weekend, on my way back from Colorado, my truck kept running out of fuel to the engine. I know all of the things to check and plan to go through the entire supply side from the tank to the factory filter. I will be installing my Holley blue and a different, better quality, non POS fuel pressure gauge. On the way out, Friday evening, it ran fine for most of the way to where I stopped for the night. I didn't start having any symptoms until I was already in Colorado. I first noticed that I was losing power at higher RPM. Then I started losing power going up hills. I finally managed to limp into Byers, CO and slept in the truck for the few hours I was able to (a completely different story). The next day, I went into Parker, CO and barely made it back to Bennett, CO before stopping at a parts store. I thought that maybe the factory fuel filter was getting plugged. I had noticed that if I shut off the engine for a while, it ran better for a while afterward. I replaced the factory fuel filter, re-engineered part of the supply side by bypassing a damaged part of the steel line that ends up feeding the lift pump. I ran out of fuel once, but go the engine started and limped the 2 or 3 miles into town to the parts store. After replacing the filter, bypassing the damaged part of the steel line (picture to come later), and then bleeding the air out of the IP, it ran great again. It started acting up again, but I managed to limp home, but the four hour drive from the night before took about 6.5 hours. The truck ran fine on short, 20-30 miles drives around here before I left for Colorado and it ran fine on a 15 mile drive yesterday.
My question is this. Is it possible that the IP can be worn in a way that it can't supply enough fuel when it's hot, after running for several hours? It's a Moose Jr. I have no idea how many miles are on it since I have no working odometer in the truck. I'm thinking that there's about 60,000 miles on it, but that's just a guess. I have no hot start issues at all. It starts with maybe 1 second of the starter cranking when the engine is at operating temperature. It was dark for most of the drive to Colorado and definitely quite a bit cooler. I'm just wondering if there's a chance that I need to look at replacing the IP. Since this is going to be a pretty involved ordeal, I'm going to wait until my vacation next month to do all of this. I happen to have a steel fuel line that's still attached to a Super Duty cab that I'll use to replace the damaged one that's on my truck now.

 

[KansasIDI]

Here's the short of it. Last weekend, on my way back from Colorado, my truck kept running out of fuel to the engine. I know all of the things to check and plan to go through the entire supply side from the tank to the factory filter. I will be installing my Holley blue and a different, better quality, non POS fuel pressure gauge. On the way out, Friday evening, it ran fine for most of the way to where I stopped for the night. I didn't start having any symptoms until I was already in Colorado. I first noticed that I was losing power at higher RPM. Then I started losing power going up hills. I finally managed to limp into Byers, CO and slept in the truck for the few hours I was able to (a completely different story). The next day, I went into Parker, CO and barely made it back to Bennett, CO before stopping at a parts store. I thought that maybe the factory fuel filter was getting plugged. I had noticed that if I shut off the engine for a while, it ran better for a while afterward. I replaced the factory fuel filter, re-engineered part of the supply side by bypassing a damaged part of the steel line that ends up feeding the lift pump. I ran out of fuel once, but go the engine started and limped the 2 or 3 miles into town to the parts store. After replacing the filter, bypassing the damaged part of the steel line (picture to come later), and then bleeding the air out of the IP, it ran great again. It started acting up again, but I managed to limp home, but the four hour drive from the night before took about 6.5 hours. The truck ran fine on short, 20-30 miles drives around here before I left for Colorado and it ran fine on a 15 mile drive yesterday.
My question is this. Is it possible that the IP can be worn in a way that it can't supply enough fuel when it's hot, after running for several hours? It's a Moose Jr. I have no idea how many miles are on it since I have no working odometer in the truck. I'm thinking that there's about 60,000 miles on it, but that's just a guess. I have no hot start issues at all. It starts with maybe 1 second of the starter cranking when the engine is at operating temperature. It was dark for most of the drive to Colorado and definitely quite a bit cooler. I'm just wondering if there's a chance that I need to look at replacing the IP. Since this is going to be a pretty involved ordeal, I'm going to wait until my vacation next month to do all of this. I happen to have a steel fuel line that's still attached to a Super Duty cab that I'll use to replace the damaged one that's on my truck now.

I had a similar experience once, with what I believe was a very worn out original pump, on a parts truck.

Would be interesting to see, if when it acts up, dump cold water on it, and see if that changes anything… I don’t remember the science behind it but that’s the ‘old Indian trick’ that I’ve heard for diagnosing this caliber of problem.

Moose seems to still make a good pump, at least in my limited experience. How old is the pump? Do you use any lubricity additives in your fuel?

 

[frankenwrench]

KansasIDI basically said what I was going to. Once tolerances get too loose, the pump acts up when hot. Cool/cold water poured over the pump will tighten these tolerances temporarily to get to a better spot to break down or simply loose power again and alot of more experienced members here used this method to diag a worn ip. Read up on alot if them back in 2017 that were older threads even back then. If memory serves correctly, one could grab an ice chest and water to "limp home" and rebuild/replace ip.

 

[IDIBRONCO]

How old is the pump?

I put it on back in January of 2015.

Do you use any lubricity additives in your fuel?

Opti Lube Simmer blend and I use it religiously.
The thing about the water trick is that I've only heard about it for the hot start issue, which I didn't have. The IP is the last place I'm going to check because I doubt that it's the problem, but I'm just wondering.
One more thing that I didn't add is why I'm starting at the tank first. When the fuel supply symptoms would get bad enough, I would stop along the side of the road, unhook the new fuel line from the filter right before my emergency e pump (which is where I connected the bypass), and then I could blow the fuel back out into the tank, reattach the rubber hose, and drive down the road again. I got fast enough at it that it was really only a 2 minute job from engine shut off to engine start. If I drove around 70, I could drive for 15-20 minutes. If I backed down to around 55, I could drive for about 45 minutes. I'm starting at the tank because I suspect a shower head pieces issue. I'm only trying to figure out if the IP could act this way because I don't want a bunch of "try this" responses. If all else fails, then I'll try swapping on another IP.

 

[gandalf]

From a quick read of what you've said, my best guess is that your showerhead is plugging up. It sounds as though you have a bunch of crap floating around in the tank, eventually plugging the intake. How long has it been since you've had the tanks off the truck? Cleaned the tanks? I'd take a serious look there.

 

[Lumberjackchuck]

From a quick read of what you've said, my best guess is that your showerhead is plugging up. It sounds as though you have a bunch of crap floating around in the tank, eventually plugging the intake. How long has it been since you've had the tanks off the truck? Cleaned the tanks? I'd take a serious look there.

I experienced the same symptoms, and they went away when I switched tanks.

Dropped the tank that was suspect and it was full of rust, my fuel filter was full of rust, shower head was broken off, and fuel lines clogged up.

Ended up replacing both tanks and all the fuel lines and that fixed everything

 

[Rdnck84_03]

I am also thinking it is something blocking flow. Possibly something getting sucked up again the pickup, or if you have any rubber fuel line it could be the inner lining disintegrating and blocking the line.

James

 

[Bart F-350]

I thought also at the showerheads.
eventually to clean the tanks I used a cement mixer and attached the tanks on it with a few shovels of gravel in there, that did the job, clean as new inside!
Off course, don't forget to give it a good flush!

 

[Laine D]

This happened to me when my selector valve was sticking but you would have noticed one take getting more full

 

[Old Goat]

A Cement Mixer to clean the tanks, that`s a new one....HMMM

When I bought the 86 10 yrs ago, the guy I bought it from said
he didn`t use the rear tank, and guy he bought it from didn`t either.
New to these IDI`s and from what I read the problems with the
FSV etc... was afraid to try using the rear tank.
Finally after 5 yrs and reading about the 38 Gal rear tank, dove in
and replaced rear tank and both Senders.
I was amazed at how clean both tanks were, no dirt, rust, Algee etc...
just some broken Shower heads. Truck was 33 yrs old at the time.

IDIBRONCO, as I remember you also just run the rear 38 also?
Yeah Iam sort of betting on the IP too.


Goat

 

[Ruffnek7tree]

I had a similar problem back in March, it was cold outside.. ran bled lines until the batteries were dead a few times, couldn't hardly get it to start.. one 10° night and leaving it a couple of weeks at a farmers house, I towed it home.. mine had good fuel flow the whole time, new e pump, so idk what it was..

Right before I was gonna replace the pump, I thought, give it a try for kicks and screams, bled it, fired right up... I'm at a loss as well.. but this time when I take it on a 1400 mile round trip, I'm gonna at least take my new pump with me lol..and maybe switch out the fuel tank somewhere

 

[IDIBRONCO]

Zombified thread, I know. Due to some personal issues that have nothing to do with this forum, I didn't tackle this until this evening. I drove the truck inside where I work, I lifted the driver's side of the bed up, and, after I pulled out the sender in the front tank, I was staring (dumbfoundedly) at a completely intact shower head. I "knew" already that this was the problem, but I was wrong. Since it was out, I did replace it with my set up of two strainers on a T. Now it's back to square one-the guessing game. I have two theories. The first one is that the mechanical lift pump is getting weak and just can't supply enough fuel over a long period of time. This may seem to be right since there was practically no fuel that ran out of either fuel line when I removed them from the sender. The part that doesn't seem to go along with that is the fact that the issue is MUCH worse when I transfer fuel into the tank from the rear tank while the engine's running. Even if I do the transfer while the truck's idling in the driveway, I can barely drive 10 miles. No problems if I transfer fuel while the engine's off, although I haven't transferred fuel and then started the engine to drive away. That leads me to my second theory. The showerhead that was on the sender had a rubber "flap", for lack of a better term, that was at about the same height as the bottom of the return line on the sender while the showerhead was attached. Even though the flap appears to only move outward, I wonder if it was starting to be defective and draw in air bubbles slowly, as the engine ran. The fuel transfer would probably put more bubbles in the tank due to the fact that it runs into the filler neck. That could explain why the issue gets worse when I transfer fuel. I guess that the thing to do is to go drive it tomorrow to see if I magically fixed the issue by replacing the showerhead. I doubt it. If not, I guess the next step will be to install my E pump. One last thing, despite the apparent lack of fuel in the lines, the truck just started right up and had no issues with air at all.

 

[IDIBRONCO]

Update: there was an air issue. I went out and drove around 4 or 5 blocks just because and the engine died right as I pulled into the driveway. It took three times of using the starter and letting it sit in between, but it started back up. I'm assuming that I just didn't let it run long enough for the sit to get into the IP before. Tomorrow may be interesting.

 

[KansasIDI]

Update: there was an air issue. I went out and drove around 4 or 5 blocks just because and the engine died right as I pulled into the driveway. It took three times of using the starter and letting it sit in between, but it started back up. I'm assuming that I just didn't let it run long enough for the sit to get into the IP before. Tomorrow may be interesting.

Do you have a fuel pressure gauge? Or do you have a way to temporarily rig one up at least?

 

[IDIBRONCO]

All I have is a POS Glow Shift right now. It kind of worked for a few days. I do have a better quality one. I think it's an Autometer, but can't remember right off (getting old sucks and don't let anyone tell you different!). I saw online reviews that said that the sender can't be mounted to a diesel engine because it can't take the vibrations for very long. If I go E pump, I will have a that gauge mounted in a remote location, between the pump and the engine. I'm not going to cut the feed line from the mechanical pump to the filter so that's not an option. I o think that I still have a broken/damaged feed line in my garage. if I can find it, I can mount my gauge and see what happens.