M35a2 Fuel issue

[nap159]

Hello all. I have an issue I hope you guys can help me with. My deuce, 1971 M35a2, Continental engine, has a fuel issue. It will not start. I replaced all filters, twice. I took the fuel tank out and cleaned it out. I have cleaned all the fuel lines. I have replaced the in tank pump. I have checked the fuel shut off position and cleaned and lubed it. I have checked everything I have found on the forums to check. I have no fuel going to injectors. I have fuel to hydraulic head. The FDC is bypassed. Is there a mechanical fuel pump on the injection pump? Please help! I am at a loss here and am ready to give up.

 

[cattlerepairman]

Have you taken out the hex plug in the center of the hydraulic head and verified that the plunger inside the head moves up and down?

Here is a useful thread: https://www.steelsoldiers.com/showthread.php?103256-M35A2-no-fuel-at-injectors

And another: https://www.steelsoldiers.com/showthread.php?57949-Deuce-not-getting-fuel-to-injectors

 

[nap159]

Yes, the plunger moves up and down, rapidly, while cranking.

 

[cattlerepairman]

Looks like it is time to try a different or new hydraulic head.

 

[DavidWymore]

Yes, the plunger moves up and down, rapidly, while cranking.

The key is how much is it moving up and down? Needs to be a good 1/4"-3/8", not just 1/8".

Put a pressure gauge in place of the fuel bleeder on top on final fuel filter.

 

[doghead]

It also must be rotating as the motor rotates.

The drivekey for the tappet shaft may have broken.

Search term "bowtie".

 

[gimpyrobb]

When you say you've checked the fuel shutoff position, did you check with the fuel shutoff cover removed?

I ask cause the actual shutoff lever operates independently of the cover.


You guys are jumping to expensive solutions pretty quick.

 

[fpchief]

Hello all. I have an issue I hope you guys can help me with. My deuce, 1971 M35a2, Continental engine, has a fuel issue. It will not start. I replaced all filters, twice. I took the fuel tank out and cleaned it out. I have cleaned all the fuel lines. I have replaced the in tank pump. I have checked the fuel shut off position and cleaned and lubed it. I have checked everything I have found on the forums to check. I have no fuel going to injectors. I have fuel to hydraulic head. The FDC is bypassed. Is there a mechanical fuel pump on the injection pump? Please help! I am at a loss here and am ready to give up.

Don't you say the words "Give Up". Fuel not getting to where it needs to be is possibly one of the easier problems to troubleshoot. Look at GimpyRobbs post!!! Also, x2 on putting a pressure gauge on top of the filter pack an x2 on checking the fuel shutof. Can you hear your in tank pump running? From what i have found, some of these will run great with the in tank pump inop, some won't run at all or very poorly.

 

[nap159]

I did check the shutoff lever with the cover off. It moves freely but does not go to 7 o'clock position. Stops at 6 o'clock. I tried manipulating it to 7 o'clock and cranking but with no different result.

 

[frank8003]

a good cheap quick installation of a gauge in the 1/8" NPT test port is good to tell if the in-tank pump is actually pumping. Put one atop the secondaries with a tee at the bleeder too, next to the #20 in the picture.


View attachment fuel system best picture.pdf

 

[gimpyrobb]

If you pull the center plug in the hyd head and turn on the power switch, you should have fuel come out.

 

[DavidWymore]

Pull an injector out and see how far the fuel shoots. Should be 3-4’. Careful, will pierce skin.

 

[whatadeuce]

you can also perform another check if fuel is getting to the hydraulic head. disconnect the fuel line that is connected to the hydraulioc head from all the filters , and turn on the in tank pump. you should see plenty of fuel pouring out of the disconnected line. if not, work backwards to find the problem. If plenty of fuel, then check that the " button" in the hydraulic head is present and connected by the special retainer to the top of the plunger. they frquently brak loose. and as already mentioned, make sure the plunger is travelling. If not, replace hydraulic head.

 

[dmetalmiki]

Post up if you found the 'cure'! We have the same exact problem with a members Deuce.
When I had that samr problem on the M54A2 after MUCH messing arround, I turnes out to be an air leak.
I am going to look at his (Our members) truck tomorrow, and "plumbing" for the first primary filter drawing air. I will post here IF that fix (On the filter) Works for us, then You might give that a shot as well.

 

[rustystud]

Did you ever check the "booster" pump ? Try pulling off the plug shown in picture two just below the socket on the left side. If there is junk in there then the pump needs to come off and be cleaned out. What can happen is the gears (shown in picture three) can get gummed up and actually break the input shaft. This pump "must" work to get the correct pressure and amount of fuel to the injection head.
The in-tank fuel pump will not be strong enough to overcome the injection pumps internal metered orifice for air bleeding and cooling.

 

[Wrenchstench92]

Did you ever check the "booster" pump ? Try pulling off the plug shown in picture two just below the socket on the left side. If there is junk in there then the pump needs to come off and be cleaned out. What can happen is the gears (shown in picture three) can get gummed up and actually break the input shaft. This pump "must" work to get the correct pressure and amount of fuel to the injection head.
The in-tank fuel pump will not be strong enough to overcome the injection pumps internal metered orifice for air bleeding and cooling.

Hello rusty. I have not been on here in a long time so I'll start by saying hello and how's it been? Hope all is well.

So I've been searching the **** out of the forums trying to get my deuce running again, and have been doing well so far. Pretty much I'm at this step now of removing the fuel supply pump on my IP. Now, what I wanted to ask was before I decided that the issue is the fuel supply pump, I did all the necessary checks first. Changed fuel filters. Check for leaks, none found. Have pressure from tank all the way to the fuel supply "booster" pump. So I wanted to ask a few questions before removing the pump because I see that I will have to remove the engine mounts and steering gear in order to get the supply pump off. So my questions are;

- I disconnected the fuel supply hose and ran my own hose into a container of new fresh diesel sitting on the floor under the truck. Would not start. Would crank and fire but soon as it fired once it would go back to cranking, will not start. Ok;

- I ran the hose up to the top of the engine bay and had a buddy of mine put a funnel into the line and fill the line with fuel. THIS TIME IT STARTED NO PROBLEM LIKE IT WAS NEW. Ok. Ran great soon as I hit the starter button it fired and idled nicely. So when I gravity feed it it runs fine. When trying to have the supply pump pull fuel it wants to start but will not run. So my question is if it ran completely fine via gravity feed, that means I have no issues in the IP itself right? I'm trying to verify that the culprit is the booster pump.

-next question is if I do have to remove the supply pump, and say I remove it and it is gummed up, will I have to rebuild the entire IP? I'm thinking if it's gummed up in there then crappy gummy stuff got everywhere. But again I'm a bit lost because as I said it ran great via gravity feed through that pump??

- Last question is, If it's gummed up and I clean it, if it's the case of the input shaft broke as you mentioned, are these available? I have tried looking and all I can find is an entire pump.

Oh one more thing. In the pictures above you mentioned to remove a plug and see if it's gummed up. I removed it from that and I don't have enough room in truck to see in there; stuck a pick in there gently and only was wet with some fuel no gummies. This is what I wanted to tell you, for that port I don't have a plug, there is a line coming out going to the starting aid injector in the intake. It's an electric pump there, and if I have the whole system connected and remove the line at the injector for the intake, and hit the switch in the cab, fuel comes squirting out of there??? So fuel is getting to the IP and it runs fine I know I'm repeating myself but if it runs fine with fuel going through the pump then it can't be gummed up??? I always used good fuel and even though it's a multifuel I havent run more than a 80/20 mix of diesel/ used oil.

Sorry for the long post rusty and who ever else is reading, just had alot of information to give about this issue. Thanks in advance guys

 

[gimpyrobb]

Sounds like your in tank pump is bad. I may have a fuel pump off an IP

 

[Wrenchstench92]

Sounds like your in tank pump is bad. I may have a fuel pump off an IP

Lol. I know the in tank pump is bad, I pulled it out of the tank it failed internally. I was told by a few guys I know that we're mechanics during the Vietnam era that told me the lift pump in the tank is not required and it only comes on cold weather issued trucks. One of them even has a deuce that he said never came with an in tank pump. I didn't believe him and he pulled his pump housing and there aren't any brackets going down into the tank to hold the pump like I looked at the casting it's just clean flush with out the mount. Yeah so what do you think gimpy? Does that sound right to you?

 

[rustystud]

I'm reading and rereading your post trying to figure out what you did. Where did you attach this "new" line on the injection pump ? Did you go through the filters ? Or did you go straight to the injection pump ?
Now since you where able to keep the truck running with this "auxiliary" fuel system that means your injection pump is working. It does sound as if the "booster pump" is the problem. Hopefully it is not to badly damaged. If it did take out the
booster gear shaft it might have also taken out the injection pumps drive gear. This is the gear that drives the boost pump.
Right now though lets just remove the booster pump and confirm if it is truly bad, then check for other damage later.

 

[Wrenchstench92]

Hey rusty, thanks for the info. It's 2:45 am here just got back with the wifey from a comedy show. We are shot and going to sleep. I will try to take out the booster pump tomorrow, I am going to have to pull the steering gear and engine mounts, correct?

Have a good night. Will be back on in the am