Pumpless!

[cbvet]

It seems to me that I recently saw something about a multifuel Deuce running without the in-tank fuel pump working.
Never really thought about it, as I figure my Deuce runs well.
Doing a little PM today, I wanted to drain the primary fuel filter. I'd guess it hasn't been drained since I got it 16 months ago. I know, I know.....
I opened the petcock & a small dribble came out, then stopped. I then remembered something on SS about switching on the power & let the fuel pump run. I turned on the switch & nothing happened.
Following the PS article, I checked the fuse. There was fuel inside the glass fuse!! Fuse was blown.
I put in a new fuse, hooked up the power, & WHAT'S THAT NOISE?
I don't think I've ever heard the fuel pump run before.
Do you suppose I really could have driven nearly 2,000 miles without a fuel pump?
I wonder if the truck will now have more power. I'm anxious to pull the old lowboy trailer with the bomber tug on it again & see how it does.
By the way. It had a 2.5 amp 250volt slo-blo fuse. Is that the correct fuse?
Another day In which I learned something. Okay.
Eric

 

[Recovry4x4]

See, paying attention in class can be rewarding. My tractor was without a pump for 6 months or so. As long as you don't open the fuel system the pump on the injection pump will move the fuel. Glad yours was just a fuse!

 

[houdel]

The -209 series manual specified a 2 amp fuse for the fuel pump; the -316 series manual specifies a 4 amp fuse. My local dealer has 2,3 and 5 amp fuses. I decided to split the difference and carry a pack of 3 amp fuses in my glove box.

 

[ken]

Usally when the pump gets dirty or clogged the load will increase and blow the fuse. I would pull the pump and clean the pickup screen with carb cleaner . Also clean out the voulte housing and impeller. Some have phillips head screws so you can pull the screens off, but some are rivited. Did you drain the filter after you got the pump running? Was it nasty? If so you may want to let the truck sit a few days and pull the drain plug on the bottom of the fuel tank and let any water/sludge out.

 

[cbvet]

With the pump running, I got a little more gunk, but not much.
In all I drained about 8 ounces of fuel, & got about 1.5 ounces of water.
I'll remember to listen for the pump running from now on.
I wonder though, if the pump is necessary. If the injector pump can pull up the fuel alright, then why have a separate in-tank pump?
I suppose a leak in the suction line could allow air into the system, whereas a leak with the in-tank pump running would leak fuel out.
Maybe just a case of over design?
Eric

 

[houdel]

Yes, the in tank pump is necessary. The injector pump, if primed, can pull enough suction to draw from the tank. However, hard starting may result, plus you are screwed if your fuel injection system is not perfect and you have/develop a small vacuum leak in the system (NOT an uncommon problem). Plus, what are you going to do when you change your fuel filters?. Every diesel system I have ever seen uses either a transfer pump or an in tank pump to keep the injector pump under positive pressure.

 

[cranetruck]

When the primary fuel filter is clean, you may get away without the in-tank fuel pump for a while, but it puts about 7 psi of pressure in the line before the primary filter.
The pump within the fuel injection pump ups the pressure to about 60 psi before filtering the fuel through the secondary and final filters.
The FDC also need a very precise pressure to operate correctly (about 21 psi).
The in-tank fuel pump reduces the stress on the IP fuel pump, particularly at high loads and dirty filters.

Like Lee says, I too think the in-tank pump serves a purpose.

 

[rmgill]

Eric, you don't check your fuel before each drive? Or at least every couple of drives? Also, when you find water in the 1st filter, you should check the second and final filters as you find water.

Though the PS Magazine doesn't say what to do if you find water in the final filter. Does this mean you've been squirting water in your engine?

 

[Pinkie]

ok so today I changed my filters, opened the bleed and cut the switch on, I waited about 1-2 minutes, didn't see anything. Unhooked the fuel line from the tank, cut the switch on, nothing. Tomorrow I am going to pull the pump assembly, clean, inspect (pump and fuse) and put it back in. I will report back on what I find. By the way I have been running my truck for about 4 months and I am sure it has not been working. I have been trying to troubleshoot a power issue and I started with the filters, which were very dirty, now I found the pump doesn't work. After I finish the fuel problems maybe by duece will get up and go!

Thanks,

J.R. (Pinkie)

 

[DDoyle]

Wanna see what effect the in tank pump has on the truck, drive down the highway at near max speed and flip the electrical master switch off - you will feel the truck shudder slightly as the fuel flow is decreased, and once momentum has disappated, you'll notice you are driving slightly slower. The same should be the case in any high-load situation, but in more 'normal" circumstances you won't notice a difference.

Best wishes,
David Doyle

 

[OPCOM]

How true this all is.. My pump did not operate today.. Hauling a M105-load of dirt and post-storm tree branches to the landfill today, "Chief Smoke" was more than a bit sluggish. I do regularly drain the petcocks, but no need this morning.. in any case after that was done, stopped at the supermarket to let my assistant go in and buy some chicken breasteses, and so I check did the primary fuel filter petcock. Only a slight dribble.. and when I opened it, the engine shuddered a bit. Shut off the engine, and went to the tank, no humming of the pump. dang it!! I'll check the fuse tomorrow.

 

[cranetruck]

Patrick, the TM calls for a 2 amp fuse, but I'm pretty sure I have seen a PS bit about using a 4 amp one. 2 amps may be marginal for an electric motor.
Some current drain measurements are in order....

Of course, check that #79 grounding wire, the only ground for the pump and level indicator, the tank itself is isolated from the vehicle frame.

As far as needing the pump, it's particularily important when the engine is working hard and with a questionable primary fuel filter. On my trip through California last Fall I had an incident at 55 or so mph on I-5, weight at about 21,000 lb. I suddenly lost power running on my "AUX" diesel tank, but when I switched to the "MAIN" tank, power was restored immediately. Later I found that the fuse had blown in the "AUX" tank pump circuit (but not after first buying a replacement pump....).

 

[gimpyrobb]

I wonder what Jdobins found out. When I changed my fuel filters, I could hear my pump kick on, but got no fuel. I ran pressurized air back toward the tank and saw bubbles in the tank, so I know it wasn't clogged. Still no fuel. I don't really want to take it apart 2 days before I'm supposed to leave for Aberdeen.

 

[houdel]

Probably the plate at the bottom of the pump fell off. They are crimped on and have been known to fall off. The pump motor spins, but without the bottom plate the pump gears just spin but do not pump fuel because the pump chamber is not sealed.

 

[OPCOM]

I got out lucky.. a bad fuse. Not that someone didn't try.. I found this 32V/20 amp fuse! Cheezwizz! that was not a smart idea.. The fuse looked decent, but sure enough it was open due to corrosion. I put a 250V 4 amp slow fuse in because I had one on hand.

Rather than listen to the annoying buzzer, I used a piece of wire to touch the 24V to the pump wire terminal inside the fuse cover. Pump ran.. I also powered it on 12V and noted that it ran but considerably slower. might be a good check to see that it can spin on 12V, and is not getting so worn that only 24V will run it.

So, yes what of Jdobins' pump? as costly as they are, it would be interesting to know what happened and how it may have been repaired.

 

[cranetruck]

It's important that a slow blow fuse is used, it can handle at least twice the rated current for several seconds considering the inrush current when the motor is first started.

 

[billymac61]

Funny I should read this today, just installed a new pump in my fuel tank. Didnt get much of a test drive but it did seem to have a little more pep. Mine has been bad for a year. Didnt know it till last week. That probley explains why my cold weather start heater didnt work, it does now.

 

[Pinkie]

I drove around for about 6 months without a pump but had an issue when I changed the fuel filters. I installed another pump and everything is fine. As long as the fuel system doesn't get opened you are good.

 

[mangus580]

Yeah... I changed my filters this weekend... NO pump
what a PITA

 

[rdixiemiller]

I found the hose popped off my fuel pump. The pump was working, but the engine was sucking the fuel up through the hose alone. Power increased with the in-tank pump hooked up properly.