Deuce won't idle

[WantOne]

I've tryed to figure out and fix the problem by reading TM's and multiple posts here on SS, but so far have not been able to fix the problem. There does seem to be multiple threads with similar issues.

Truck is a 71 M35a2, non-turbo. I've only had the truck for about 9 months and it's been pretty much trouble free. I did change the fuel and oil filters a few months back.

A few weeks back I purchased a winch. Drove it up to the shop and it sit there for 3 to 4 weeks while I got was working on it.

Finally got it all bolted back together and went to move it. It starts up, but then won't idle. You can keep it running if you keep your foot working the throuttle, but anytime you let off the pedal it dies. Will start up, but then die again.

From my research it sounded like I had a fuel issue. I went through and pulled all the fuel filters back off, replaced the rubber gaskets that seal the canisters. Used o-rings on the top of the secandary and final since the rubber that was there was just about gone. Blew air through lines to make sure no blockage. Pulled pump from tank to make sure the pickup wasn't clogged.

The only thing I found was that the copper line from the primary across under the radiator was damaged, but did not appear to be restrictive. Rubber hose that connects to this copper line and up to IP was pretty badly cracked, but doesn't appear to be leaking. Couldn't find anyone to make one, no one had the fitting that goes to the copper line, will have to find a source for this line.

After putting everything back together, loosend vent on top of secondaries and primed the system in less than a minute. Started right up, but still won't idle. Really wanted to take it to an event this weekend so I'm hoping to come up with a fix this week.

Do I have an HH problem? Should replaceing the HH be my next step?

Thanks for anyones help with my problem.

 

[sandcobra164]

Next step would be to pull the cover off the side of the IP and ensure the fuel cutoff rod is not sticking. Many threads to read about that issue. I don't have a picture but I'm sure someone will come along that does.

 

[WantOne]

So the fuel cutoff sticking would allow it to run, but not idle?

 

[maahes]

I had a similar problem, stalling when RPM dropped to idle. While my truck initially started without issue a dozen or so times after the stalling issue began, it developed into not starting at all without ether/silicone. Yours still sounds like it starts without issue so that's a plus.

I agree check the fuel cutoff, it could be stuck partially closed starving the HH when the RPMs are low, at higher RPM there is higher pressure at the injectors compensating for that stuck valve. (all my theory someone correct me if I am wrong as I am no Diesel mechanic)

My cutoff was not stuck, and I finally resolved the issue with a new HH.

My thread for reference if you want to compare notes: http://www.steelsoldiers.com/deuce/93262-deuce-failure-start.html

 

[WantOne]

Ordered the rubber hose from White Owl. While waiting for that I think I will change the fuel filters out again even though they are not that old. I'll also look at the shutoff.

 

[Floridianson]

You might try and increase main fuel adjustment a couple of flats at a time and see if she does any better.

 

[moriboy]

Sounds similar to what mine was doing a few months back. It would run just fine but would not idle. After going thru the entire fuel system, I finally figured out what it was....evidently there was a bit of water in the bottom of the tank. I ran the tank pretty empty and had immediate problems. I drained the tank, replaced filters, etc, etc. I could get her started, but just wouldn't hold an idle. I finally pulled the pump and discovered 2 of the 6 ports in the hh had water in them. Now I replaced the pump, but I am confident that had I got the water out of the original one, it would've run fine and I would have saved $700! Doh!

 

[WantOne]

Yesterday I went to NAPA and got new fuel filters and replaced them just to eliminate filters as an issue. Once I replaced them and bled the system she started right up and idled....YES.........NO.........as soon as I gave her some throttle she rev'd up and then went back to not wanting to idle, and dies if you don't keep your foot on it.

I'm hesitant to turn up the fuel since it was running fine, wish I had a spare HH to troubleshoot with. Hopefully I'll get the new rubber hose this week and see if that matters.

 

[kennys@wi.rr.com]

If your fuel shut off is sticking it will block just enough fuel to cause such an issue. I have also seen this problem happen due to the o ring on the fuel shut off valve. Also make sure the secondary filters are seated into the groove on their mount. It's amazing how often people replacce those filters and still don't get the can on right. All it takes is a small amount of air and it will caause problems. I know I did it myself a few times in a row, it can happen to anyone. Just some things I would be looking at if it was mine.

 

[WantOne]

While waiting for the new hose I'll look at the fuel shut off.

Have tried to make sure the canisters are seated properly as I've had them off and on several times now. Could still be an issue, but I have been careful to make sure they are seated.

Did order the JTonka spin-on's last week, hoping to get them any day.

 

[stumps]

Just because water was mentioned, and to be totally clear, there are 3 fuel filters on the deuce. The first is the primary filter which is a water separator/filter, and is located under the alternator.. Being in a hidey hole, it gets missed by a lot of new deuce owners. The second and third are side by side near the back left side of the engine. All three filters have water drains on them. For water to get into the injection pump all three would have to be flooded... something that should never happen if the truck is being maintained.

A common cause of lack of idle is a rusted up shut-off rod where it is exposed on the side of the injection pump. Because most people leave the fuel shutoff control in the safe "OFF" position when parked, the rod is exposed to the weather, and can rust. If that happens, the rod can stick before the fuel turns on all the way... The "ON" position is set by a little light weight spring that pulls the rod into the pump... The O-ring KennyS mentions is also another common problem.

-Chuck

 

[moriboy]

Yep, my mistake on the water, it happened on my recovery, but none the less it did happen. When one or more cylinders are not getting fuel, idle problems will happen....

 

[WantOne]

Was able to look at the throttle shutoff rod tonight. Pulled the cover, everything moves smoothly with no binding or sticking. Since issues related to this seem to be when the shutoff rod does not work smoothly I did not take it any further apart.

After putting the cover back on I tried to start the truck. It started, then died. Tried again and it almost died then reovered and idled right at 1000rpm. I then let it sit there and run for 15 minutes.

Tried reving the engine and it revs up, then then when coming back down it won't hold an idle and dies. Start it up again and can keep it from dying if I keep my foot on the pedal. If I feather it right it will again idle.

After letting it run a little longer I shut it down using the engine stop lever.

Wondering if I take it out and drive it some it would help, but don't want to get stranded, and don't like the idea of not finding something actually wrong. Always in the back of my mind that it could do it again.

 

[marchplumber]

I had an idle problem also. I had mixed fuel in the system. (part diesel, part gasoline) The FDC was/is still hooked up. Trk started and ran, but would die when you took your foot out of her too quickly. She started back up, but down shifting and turning were a real problem. Took her to a professional diesel mech. He found nothing physically wrong. We drained tank, filters, and fuel system. Refilled with fresh diesel, and she has run good ever since. I no longer mix fuels though. LOL I know of no "cause" but, that's what happened to me.
God bless,
Tony

 

[WantOne]

Update - Last night I got home late so thought I would just start the truck and see what it would do. It started right up, died. Started it again and it almost died, then idled. Does idle a little high, but that's because I turned it up a bit when initially trying to figure out the problem.

I let it fill the air tanks, then took it for a drive down the road. It seems to be almost dying when taking my foot off the pedal, but recovers.

So it seems to be getting better even though I really haven't done anything. Maybe I just got some gunk in there somewhere and it's working it's way out.

Just received my spin on fuel filters so will do that upgrade along with the new rubber hose once I get it. Considered bypassing the FDC just to see if that made any difference as well.

 

[rattlecan6104]

Did you say you used rubber O-rings for the canister nuts on the filters? If so they are not necessarily designed to be used on surfaces that are twisting together as this action tends to cut them, this is also why you never twist the canisters because you can cut the large O-ring that seals them to the filter head. Since you got a set of spin on filters this would essentially not be an issue for long. As far as the FDC, this is just my specific situation, but my FDC was bypassed and I had been running mixed fuels like it was going out of style. Usually every time I had a bad idling problem, or stalling problem, it has been air leaks getting into the fuel system... that or some @$$ hat pouring water into my fuel tank, my remedy for that was draining all the fuel and replacing everything with fresh diesel, a quick spray of ether, and off I went.

This was a long winded way of saying that I think you still have a leak that is introducing air into your fuel system somewhere.

 

[WantOne]

Received my new rubber hose from White Owl and installed it Friday night. When I removed the hose I didn't get any fuel out of the line which didn't seem right, I expected the line to be full of fuel.

I can't say it really made a difference, truck still almost dies, then recovers when you rev it, or let off the pedal when shifting, but it seems to be getting better.

Saturday I drove it to an event about 45 miles each way for a totol of around 90 miles. I'd have to say it does seem to be getting better.

Sunday I installed the new primary spin-on filter. Did notice that the indentations on the old filter just barely hit the cork gasket on top. Nothing in there to keep the filter centered. Maybe I was missing something else in there. No matter now with the new spin-on.

Was going to do the secondaries as well, but the rubber o-rings I replaced on top of the secondaries were torn up again. Washer was also deformed some. I'm going to get new o-rings and use new washers I had that are a little thicker.

 

[PsycoBob]

Aren't the secondary/final stock gaskets flat? I thought when I replaced mine that's what I used.

It sounds almost like your copper crossover pipe is the problem. Since you have a new hose on order, You can try cutting off the old rubber hose from the barbed ends- replace it with a 3-ft chunk that you can drop into a fuel can & try firing it up. Oh, clamp off the remaining end attached to the copper line, or pull the electrical plug from the tank pump.


Wait, you added a winch? Replace the copper line- you smooshed it. The rubber hose might be borked too, but that copper line's flatter than you think. Soft copper line can be had at Home Despot or Lowes. Try not to cry at the price.

 

[WantOne]

The comments about the o-rings not being designed for a twisting motion make sense, but I've not found what should actually be used for the secondary and final canister nuts. I'd had a couple of people tell me o-rings, but when you tighten them down the washer will turn and probably damage the o-ring. Maybe as long as it's not taken on and off it will be fine. If someone knows a source for a flat rubber washer/seal for these nuts please let me know.

PsycoBob, copper crossover line is damaged and apparently has been that way for some time. Didn't just happen when winch was installed. Will eventually replace but it appears this is something that has to come from a parts truck so will have to source one.

 

[Keith_J]

Sounds like you need to adjust the idle. If your hand throttle works, use that for preliminary measures to see if you can get a stable idle.

This injector pump is like all other mechanical pumps as it has a governor. When you smash on the right pedal, you command the governor to a higher RPM point by increasing the tension on a spring. This increases the spring force which must be balanced by higher centrifugal force from the flyweights.

Well, at idle speed, the spring force is a trivial quantity, it still must be balanced by a tiny centrifugal force. Since the entire linkage is inside the tail of the injection pump, it could be the external oil drain line is plugged. Or the linkage is gummed.

I would use the hand throttle, I've had to use it on a few.