NJTman

Ok, I'll post the facts then the suppositions...

Facts:

• Owned truck about 7 years Never broke down other than from IP leaking.
• I plow snow, therefore I'm in the cold weather 2.5 months out of the year
• About a year or so ago, I replaced the original 23 year old lift pump, as it's pressure was down about 2psi at wot.
• New fuel sending unit in 2015
• Fuel filter is Fleetguard FS1221
• New (CUMMINS) lift pump is from China, and it seems to be fine. At idle, it fluctuates between 7 to 8 PSI, and under WOT it runs about 4 to 6 psi.
• IP was rebuilt a few years back. Again said, never broke down other than IP
• I use Power Service white bottle each fill as directed. Yeah, some don't like it, but it's never been an issue, so MRA

Here's the problem.

• 2-3 months back, we had a snow storm Truck, as usual ran flawlessly. I decided to take an 8 mile ride to an old snow plow job I used to do because I was ....... uh.... curious 6 miles out, and the truck dies out on me. 18* F on a 50MPH highway and big wind block on the front of the truck (plow). get the truck running again by replacing the filter with new even though it had been changed only 2K miles previous. Ran great. No issues.
• Plowed snow on this past tuesday from 7 am to 12am the next morning. Truck never sputtered, hicupped, or anything unusual. Like a clock.

Yesterday...

• Need more salt.
• Head south to HD for a few bags. 14 mile trip.
• Had plow still on truck.
• Get to HD, load truck, get about 4 miles towards home, on a highway @ 50mph truck dies out. Exactly as previous. Stranded in 18* weather for 3 hours.
• Frostbite on toes was beginning.
• Wife shows up
• My 40 year of experience diesel mechanic buddy comes down from North NJ to help me out.
• Wife hands me new filter.
• Diesel buddy pulls filter off, and it's almost completely empty. he fills new filter with fuel. Hand primes pump (it worked when the filter was off although he's used to "BIG RIGS", and said my stream looked a little weak (he must have been talking to my urologist to come up with that one).Bleed the injectors, struck fires up immediately, and never skipped a beat.Runs fantastic again.

Stopped for pizza with him, wife, his wife, and trying to pay him back for his 3 hour round trip for a stupid filter being empty.

I ask my "40 years of experience with diesel rigs" friend this question:

"why did my truck break down under the exact same conditions both times? 18* weather, plow on front blocking radiator. Is the fuel filter freezing up because it's not being warmed by the airflow? ".

He looks at me and replies...

" In 40 years I've NEVER seen a fuel filter freeze up (he said gel up) unless the outside ambient temperature is 0* F or less. You dumped the filter, right ? What did the fluid look like ? was it clear as normal fuel or milky, yucky consistency ? "

I replied.... " It was clear as new fuel. ".

So the dinner goes down, and he says "you have a Fuel pressure issue, or an air issue. How full was your tank in both instances ? " I tell him that I had about 8 gallons in there this time, and I can't remember previously what I had.".
He says "Fuel pickup tube in tank good ? " I say yes, it was, can't see in there now, but I've run the truck down below 8 gallons before.

Tells me to check fuel PSI. Checked it on the way home, and it was running normal 7 to 8 psi. WOT 4 to 6 psi.

He says.... "Find out what the spec is for that lift pump. Sounds weak like your pee stream".


So, now what do I do ? He suggested putting in an aftermarket pump that would supply more fuel pressure. I could upgrade to the new cummins version, or as he suggested, an inline fuel pump just forward of the tank.

What say the gang ? What do I look for next, besides a fuel filter wrench, a 17mm wrench, a gallon container for diesel to keep in the truck, a bunch of new filters, and some hand cleaner and gloves for replacing the filter the next time, should it occur.

Free beer and hot wings to the guy(s) who figures this out with me

maybe368

Hey T, How are your rubber fuel lines? They can sometimes split lengthwise, for lack of a better wprd, without showing externally, kind of like an aneurysm. It seems that the problem is from the tank to the LP (Thanks Captain Obvious).IIRC, the VE dosn't need much pressure and is suseptible to leaks when over pressured and doesn't really need a lift pump either...Mark

Lary Ellis (Top)

You can tell when you got a bunch of old farts in the forums.....they all post with medical terms

Yeah I am guilty as charged

NJTman

Well, today, impossible to see. Wouldn't it be leaking ?

maybe368

Not necessarily, the aneurysm can open up to the inside, unfortunately, when it happens to people, the first sign usually is stroke or death, in the case of AAA, Abdominal arotic aneurysm. The fault could also change with changes in pressure. You could try putting a few PSI's into the fuel tank to see if there are any leaks, suction side leaks tend not to leak...Mark

maybe368

Yeah, even though I have been retired for 14 years, it's tough to forget 26 years of being a paramedic, besides, it makes you sound smart ...Mark

oliver foster

T-man,
I am thinking sucking air from:
Bad fuel lines
Bad fuel line connections.
Something from the fuel tank to the LP.

If it always happens when the fuel tank is low, it might even be a hole in the fuel sending unit itself. Which is exactly what my '91.0 is acting like. The '89/90's have the earlier tank and fuel pick up style which has metal lines inside it. I am picturing a pin hole has rusted in my pick up line. The '92/'93 [like yours] should have nylon fuel lines in the sending unit.
I am planning on dropping the tank next week and inspecting it.
I might swap it out for another spare '89/'90 sending unit I have...OR I just ordered a fuel sump kit that I might drill on the the bottom of the stock tank for a new fuel pick up location. Regardless new fuel lines and clamps will be happening on my '91.0.

Give me a ring if you want to problem shoot the old truck with me.

gyman98

I would say air leak on a supply line as well. You could use a compressor regulated to 10psi and pressurize the tank for 5 mins or so

deere country

I would say the same thing your buddy asked you about, the pickup/sending unit mechanism. The only way you can "know" if it's good is to take it out and look at it outside the tank.

The nylon lines they used on the 92-93 truck are nearlly always flawless and without any trouble. The only trouble I have ever seen them give is when someone adds something in or on the frame that chaffs a hole in them. If they are left alone I have never seen a problem with them. The only other two things would be the in tank pickup assembly or the seals inside the nylon fuel lines, again I have never seen them fail myself.

1STGENFARMBOY

I say you have a hole in your catheter.

NJTman

Well, that doesn't sound sexy. My girlfriend would be disappointed, and most likely tell my wife...


Not that it would mean anything to her....

NJTman

I've had the tank down several times. Never noticed anything unusual in there. Seals replaced each time. Clean as a whistle in there at least a few years ago...

deere country

Well sounds like your getting good at taking it out! I would come up with something to pressurize the tank and keep it pressurized over night. If you don't see anything wet from the tank to the lift pump then you know you need to pull it down again.

ofelas

1/ loosen return line banjo on ve and put 5psi air into he fuel tank for a couple minutes.

2/ check return line integrity behind filter mounting pad and on rear of block

3/ disconnect lift pump feed line drop into a bucket of diesel and idle for an hour or so.

Tape/extend line into a 5 gallon jerry can of fuel on the passenger floorboard or in the bed and roadtest for a couple hours.

NJTman

For all you picture fanatics....

Here's me being "broke down"....


and here's me using my butane torch I had in the truck to unfreeze a door lock on my storage unit for the salt bags. Being 18*, on the shore, with sweaty feet, that started to tingle and get frost bitten, I used the butane torch to heat my feet up while I waited the 3 hours sitting there for my saving diesel buddy, who'm I'm forever grateful to....

Note to self. "Dodge" emblem on glovebox ? Melts very easily when torch is applied....