My guess is fuel delivery issue...

[Loco_Hosa]

Hey yall, Im still very new to Deuce ownership, so my guess is that is something stupid, but I wanted some input and suggestions before I go and muck it up worse.

• If you do not want to read the whole explanation, but you have something to contribute, then skip to the Bold section.

Yesterday I completed the first oil change on my truck, along with forum member Barneyszoo (Phil)s help, and then we filtered the old oil and dumped it into the tank that was about 1/3 of the way full of Diesel. We all fixed all the lights on the truck, so I decided to take a bit of a test drive this evening. Now its giving me fuel issues.

This was the first time I drove the truck after dark, with the headlights on. Started fine, but then was sputtering a little bit on a small hill. (2000 RPM, 5th gear) At first this was not a big concern, but it got progressively worse. When we got off the freeway it died at the light, and didn't want to start back up. Shortly after that we had traffic lights on small uphills and even in low range 1st it wouldn't move, and would die when I tried to change gears.

When I arrived at my destination I let it sit, the engine cooled, and it drove to the freeway just fine, but it wasnt long before on the slightest hill it was sputtering and struggling to maintain 50mph. My thoughts went to the fuel being too thick from the WMO, didnt seem like we had enough to make the difference, but just to be sure I pulled over and added 5 gallons of unleaded fuel, I was 100% that would thin it out enough. On flat surface streets it would accelerate to speed just fine, but when I got back on the freeway I had to fight to keep speeds of 45-50, and you could hear the turbo spool up after each time the engine sputtered.

I did finally get it home, and I noticed that if the fuel pressure was given a chance to rebuild pressure, for example keeping my foot out of it and the engine in gear as I gradually slowed to a stop, the engine wouldn't die when I put the clutch in. This is a new problem, when I drove the truck to my house (70 miles) we had to go over a mountain pass and I had no power troubles at all.

The upside to all this is that I got a lot of good practice downshifting and double shifting (I think that's the term) and my roommate got a kick out of the fact that when I was loosing power in fourth, instead of going to third I went to low fifth, which made the next downshift easier and kept me more in the power.

To sum it all up, progressively worse throughout the evening, the truck seemed to be having issues maintaining fuel pressure. This resulted in failure to idle when leaving the freeway, and surging power. Refused to start on a hill.

I have theory's:

• The WMO made it too thick, or has clogged something up.
  • I added 5 gallons of unleaded to combat this, with no success.
• The electronic fuel pump is not getting enough power with the lights on.
  • Ill drive it tomorrow in the day light to see if there is any difference.
• The fuel pump/fuel filters/injection pump is clogged or failing.
  • I have not done fuel filters yet, does anyone have the Napa parts number for them? How much are they? Can you point me to the section of the TMs that deals with servicing the fuel filters?

These are my best guesses, but before I get my ass stranded or throw parts at it I wanted some other more informed suggestions.... Thanks all.

 

[wsucougarx]

Primary Fuel filter NAPA 3511
Secondary Fuel Filters NAPA 3512 (need 2)

I think I paid $6 for the primary and $9 each for the secondaries

Now I'm sure you know this. The primary filter sits under the alternator/generator and the secondary/final sit at the rear of the engine on the driver side. Just an FYI just in case you didn't know. The primary fuel filter is shorter than the secondary/final filters.
Not much in the way of servicing them. However before you change out the filters I highly recommend you drain your fuel filter housings, put back pressure (using an air compressor) on the fuel line starting at the final/secondary fuel filter housing to get all the old fuel/gunk out of there, completely drain your tank and clean it with kerosene. Get as much garbage out of your fuel system before replacing filters.

Once you get your new filters installed you'll need to purge the air out of your fuel lines. On the top of the final/secondary fuel filter HOUSING there is a pressure relief screw/bolt. Simply open the bolt/screw, turn on your master switch and wait for fuel to come out of valve. Tighten bolt/screw and attempt to start her up.

Hope this helps. Let me know if you have any questions.

 

[glcaines]

You almost certainly have clogged fuel filters.

 

[LowTech]

I too would say filters if they were not changed w/ the oil.
The other thing that doesn't get mentioned much is the hose from the in-tank to the top plate. I've had to replace the hose clamp on them for both of our truck. Full details here, Surging

 

[gimpyrobb]

Start with the filters.

 

[Heavysteven]

Filters ditto

 

[bill2444]

Whenever there is a driveability/power problem with older mechanical diesels, check fuel filters first. Then air filter second.

 

[kennys@wi.rr.com]

As stated already change the filters. Try to avoid using unleaded, it has a drying quaility to it the IP and HH do not like, try kerosean next time you want to thin oil. If the filter change doesn't work, pull the fuel pump out of the tank and check the hose from the pick up to the pump. There is a recent issue with these going bad or the hose clamps giving out and then sucking air. Another thing to try is crack all the injector lines loose at the injectors and bleed them out. If all this fails you may have to clean the injectors, I can't help you with that one, but do a search and you will find a wealth of info on it. If all else fails you will need to look to the injection pump itself, let's hope it doesn't get to that point.

One question I have, is your FDC bypassed?

 

[Loco_Hosa]

FDC, as far as I know, is not bypassed.

I pulled the filter housings and caught the diesel in a "Drip tray" (Might have been a cake pan, dont judge me) and the primary filter housing had no water in it, but was FULL of heavy grit, almost looked like gravel (Will post picture) so I am rather sure I have found the problem. Napa was closed by the time I got it all apart today, so tomorrow I will go pick up the new filters and a spare primary. I dont have the resources to drop the tank till I drive back to WA, so I just have to hope for the best till then.

Im about 90% sure that replacing the primary will fix it, and one of the secondary's were coming apart, so I look forward to seeing how she runs after Im done.

I just cant believe the size of the grit that made it past the fuel pump....

 

[kennys@wi.rr.com]

How are you filtering the oil before you put it in the tank? Whatever it is it needs to be filtered better.

 

[tm america]

i started having a similar problem with my truck down at haspin and the ride home was horrible. MY truck would act up every half hour or so mostly on hillls or when taking off from a stop.. as i would hit the throttle to accelerate, it would fall on it's face like i pulled the fuel cut off... First thought was change the filters so i did ran fine for 30-45 minutes then it did it again ... Then it was fine for the rest of the time down there.. But when i hit the road home i noticed it would do it every big hill once i laid onto the throttle.. I would let off the hit it again same thing three or four times,,Then if i laid into it easy it was fine.so i pulled over and changed the filters again and cleaned the filter cans.. Same thing? So i pulled over the pulled the intank pump out screen was getting some hair or lint on it so i stuck my arm in the tank .The bottom of the tank felt nice and clean no grit.. so just to be on the safe side i didn't run it back through the screen ..
And with all of this still no change ...my next step is to change the ip and put my other turbo back on there.. I"m pretty sure the problem is in the fdc or governor,,, Maybe mine my be the accelerator arm or something like that,,,But it never felt like the filters were getting clogged it never had a hard time getting up to 2600rpm. it would just fall on its face like i pulled the fuel cut off out the let it go .. It wouldn't die out just did nothing.. >i hope your fuel filters take care of it.. If not maybe we are chasing after the same issue

 

[Loco_Hosa]

How are you filtering the oil before you put it in the tank? Whatever it is it needs to be filtered better.

I had only added 5 gallons of oil to a part full fuel tank. I filtered it with a paint strainer, (I know, not a perfect solution) but this grit I am guessing is from the truck sitting for a long period and gathering sediment in the tank. I can tell you that the oil I have added to the system is NOT responsible for even a fraction of the grit I found in the filter housing.

Ill update tomorrow afternoon

 

[LowTech]

I dont have the resources to drop the tank till I drive back to WA, so I just have to hope for the best till then.

You don't really have to drop the tank. There's a plug in the bottom. If you take the pump out (which you can do on a cargo bed) to check the hose, you will have access into the tank.
I drained, filtered, refilled, drained, filtered, refilled a few times. Leave the last bit in the bucket every time it gets poured.

After running 5 gals through it a few times, and using a scraper inside the tank to loosen all the grit and help it to the drain, it was pretty clean. Can't get past the baffles but it will help loads. I did find a small collection of things inside, old pump shims, fill-tube filter pieces, grit, rust.

 

[gimpyrobb]

In the picture of your grit in the fuel, it looks like you might have one of the fiber-reusable filters. If you haven't thrown it away, don't!

 

[LowTech]

In the picture of your grit in the fuel, it looks like you might have one of the fiber-reusable filters. If you haven't thrown it away, don't!

Dang, I had one of those once . . . `course it was caved in on one side, maybe I should have saved it and tried to straighten it.

 

[Loco_Hosa]

Alright, after getting the new filters today, I think the old primary filter was doing next to nothing. It looks like at some point someone didnt have the correct filter, and used one with a much smaller inner diameter, and the piece that was supposed to sit under the filter and over the spring was discarded and replaced with a washer that *Almost* covered the opening on the bottom of the filter.

The problem is that the piece that should sit under the primary filter is gone, and without it the new filter will not stay in the center.

Is this a piece I can get at Napa? Or will I need to find someone that has upgraded to spin on filters and try and rob it from their pile of spare parts?

First picture is of the filter I took out and the filter I am putting in. Notice the inner diameter. Second shows how the old filter was mounted, although is upside down. Third is of the piece I am missing, the spring is there to show how it was oriented. I "borrowed" the one in the picture from the secondary filter housings.

 

[Barneyszoo]

Also if the tank has not had a full tank of fuel it will develop rust above the level of the fuel if it sits for awhile, then when you add fuel it nocks it loose. Diesel fuel colects moisture.

 

[cbvet]

I would suggest the cheap & simple spin-on primary filter as "designed" by BillW on this site.

 

[cranetruck]

If you can find them, there is another choice for the primary filter, used on the 1969 m656 8x8 series trucks, shown below. No filter element to replace, just turn the handle to clean and drain...

 

[Loco_Hosa]

Well, after getting a hold of DUG's old secondary filter housings I was able to rob the pieces for the primary fuel filter that I had needed. Had to drill out the center just a touch, but the truck is running great now. I did buy a spare fuel filter, and a crescent wrench so I can change it on the road side if I need to.

Thanks for the help!