[Eskimoman]

I have an issue relating to my '88 F450 diesel running out of fuel both when sitting for a couple of days and sometimes when driving down the road. First the truck: 1988 F450 (Super Duty) 7.3 diesel with dual tanks.
The problem: I first noticed it last fall when it began to get cold (Maine). After finally getting it started I made sure to plug it in every night problem solved, or so I thought!
Within about three weeks I'm out plowing and the truck acts like it's out of fuel - throw the switch - swap tanks and it continues on just fine for about an hour. Suddenly it acts like no fuel so I switch back to front tank, it pick up and goes on. I must have swapped tanks eight or ten times that day.
Finally about two months ago it stalled acting like it's out of fuel and would not start. I had it towed to my mechanic and he came back with there was no fuel from the low pressure pump up so he replaced the low pressure pump! Got the truck back and all appeared to be fine. I have started the truck a couple of times over the last two month, took a three or four mile trip down the road a week ago and all was well. I drove the truck about five miles last evening from my office to home and it ran great. Went out about an hour ago - truck fired right up and ran about a minute and a half then stalled! It is acting like it's out of fuel once again!!
Over the last year the low pressure pump has been replaced, the switch system on the frame rail back by the drivers' side tank ($500.00+), all of the fuel rail hoses, fitting, etc. on the top of the engine, fuel filter twice, the tank switch on the dash and who can remember what else.

The real problem seems to be that the problem comes and goes without any rhyme or reason. The mechanic seems to be just guessing and replacing the next part in line - I don't have the time or money to keep going like this! Is it possible that both sending units are bad in both tanks at the same time? What are the odds of that? I am open to anybodies ideas thoughts - anything short of just setting it on fire.

Thanks all for reading and any help you may offer.

Eskimoman

 

[Billrhowell1988]

You have probably already checked it, but have you taken your tanks down and looked inside of em? My fuel pickups shattered and were getting sucked into my fuel intake in the tank and i had to clean out my tank and blow air down the line from the tank valve( i dont know what its called) to get all the little pieces of out the line.. just a thought though.

 

[drinkypoo]

Is it possible that both sending units are bad in both tanks at the same time? What are the odds of that?

If you're using both tanks the odds are high. Mine went within months of each other but I was mostly using only one tank since the sender in the other one didn't work. They were cracked and gummy as if from chemical attack. This was around the beginning of winter fuel season. I would check them. It may be easier to raise the bed depending on the state of the hardware.

 

[ARIZHNT]

Mine too, I had to make new pickups with 3/8 hose clamped to the tube and a piece of aluminum screen on the end to keep out debris. V-cut the ends to keep the hose from bottoming out on the tank. Works great.

 

[lexxxel]

I drove the truck about five miles last evening from my office to home and it ran great. Went out about an hour ago - truck fired right up and ran about a minute and a half then stalled! It is acting like it's out of fuel once again!!

Eskimoman

sounds like an air leak. It starts and then stalls out. How much fuel is in the tanks?

Did you replace the return lines, caps and orings?

 

[Eskimoman]

Hi,
You know what - i don't think either of the tanks has been taken out and looked at since I have owned it (4yrs). Guess I know what I'm doing later this weekend.
thanks for the idea - I'll let you know what I find.

 

[Eskimoman]

Hi,
Now that I think about it the fuel gauges have never registered right. What happens is after filling both tanks each reads over the full mark. I have occasion to drive for five or six hours at a time and the gauge will slowly drop just below full then after a while suddenly to around half a tank. Then after driving for another hour or two suddenly drop to and eighth of a tank. I wondered if there wasn't a wiring issue somewhere due to the jerky movement as the gauge drops. Anything other than a full reading is never correct. It has read half a tank and I have run out of fuel so I never trusted it from the beginning. For the most part I always keep both tanks topped off at all times.

 

[Eskimoman]

Hi,
For the most part both tanks are never left with less than 3/4 of a tank for any length of time. I'm surprised - I knew that the gasoline tanks are pressurized when driving but had no clue that the diesel tanks are also pressurized - learn something new every day! I'm starting to think I need to start at each tank and replace the fuel lines and clamps to address a possible air leak.
Again, the problem has this come and go thing - you would think that after a year plus that whatever is wrong would has just let go and totally failed by this time.
Does anyone happen to know where I can get new or rebuild pick up unites for each of the tanks? The driver side tank is the standard Ford tank. The passenger side is a poly cube shaped tank and an aftermarket. Is there a Ford 19 or 20 gallon tank out there that would mount to the outside frame rail on the passenger side?? That would get read of the poly tank (about 15 gal cap.) and increase my total fuel load with a 20 or plus gallon tank.

 

[mbass777]

check Rock Auto they have gas tanks new cheap or at least I think there cheap