Farm Equipment - AC diesel cuts out

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AC diesel cuts out

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=190876
Printed Date: 18 Jul 2025 at 11:02am
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Topic: AC diesel cuts out

Posted By: RRF
Subject: AC diesel cuts out
Date Posted: 24 Sep 2022 at 8:50pm

Friend of mine has an AC 3400 engine hooked up to a piece of wood working equipment. Engine starts great and runs fine for a few minutes and then it shuts off. Can be restarted no problems right after and then it shuts off again. Like it is starving for fuel but there is plenty of good clean fuel supplied to the injector pump. Injectors have been rebuilt fairly recently. FWIW I know very little about diesel engines other than how they work in theory. Any pointers would be appreciated.

Replies:

Posted By: SteveM C/IL
Date Posted: 24 Sep 2022 at 9:41pm

Kinda sounds like the governor ring is going out plugging the return. Some say you can loosen the timing window to relieve fuel pressure and see if it keeps running.

Posted By: MACK
Date Posted: 24 Sep 2022 at 9:43pm

loosen two screws in timing window until fuel leaks out. If it is ok with fuel leaking out, return in pump is plugged. Time for a rebuild. MACK

Posted By: gleaner1
Date Posted: 25 Sep 2022 at 10:30am

The rebuild will cost almost as much as the motor is worth.
Remove the darn check valve, blow the line out to be sure its clear and call it a day.
Been there done that on a couple.

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ALLIS CHALMERS "The color is orange"

Posted By: allis1221G
Date Posted: 25 Sep 2022 at 11:15am

Had the same thing with 185, took little fitting off the top of pump little ball inside, fitting was pluged cleaned out and runs great.

Posted By: RRF
Date Posted: 25 Sep 2022 at 2:22pm

Thanks guys for the suggestions. From what I understand, there are 2 pumps on this engine. Other diesel hacks have talked my friend into purchasing an electric pump to bypass what he calls the low pressure pump that supplies what he calls the high pressure pump. That part is done and works fine. Separate new plastic tank, for testing, is ensuring a good clean supply of fuel. The pump you guys mention, is that where the timing window is and the ball that allis1221G refers to? Gleaner1 where is the check valve that you are referring to? And remember guys, I am a bonified greenhorn with the diesel engines. Thanks again

Posted By: DougG
Date Posted: 25 Sep 2022 at 4:43pm

Pump rebuild cost as much as what the engine is worth ???? Highly doubt that ! LOL

Posted By: SteveM C/IL
Date Posted: 25 Sep 2022 at 5:15pm

For the guys who don't fix their problems how do you handle other situations? Not correcting a pump issue doesn't make sense to me. Farmer fix and just roll on? Really?

Posted By: RRF
Date Posted: 25 Sep 2022 at 6:55pm

Hi Steve. If your comment is aimed at me, then all I can say is that I believe you are witnessing a case of the blind leading the blind. That is partly the reason I joined this forum. The hope is to get guys like you to steer us (me) in the right direction. I see this situation as an opportunity for me to get some exposure to the workings of diesel engines. All input is appreciated.

Posted By: MACK
Date Posted: 25 Sep 2022 at 8:27pm

Yes, it will run quite a while if you remove inside of fitting, but when it cuts the pins off governed rings it will stop in it's tracks then it will cost more for a rebuild . MACK

Posted By: shameless dude
Date Posted: 26 Sep 2022 at 1:02am

change the fuel filter

Posted By: SteveM C/IL
Date Posted: 26 Sep 2022 at 6:45am

Not you RRF. The guys giving poor advice. You ask what to do. They suggest a shortcut. The flush and go is for the guy trying to finish planting, hay or whatever until there's time to fix it right. MACK explains why the shortcut is a bad idea long-term.

Posted By: injpumpEd
Date Posted: 26 Sep 2022 at 7:22am

And make sure the return circuit to tank is open. Just because you knock the ball out of the return fitting in top of injection pump doesn't mean it's fixed. The real issue is the plastic flex ring inside the injection pump has broken down and the pump needs serviced by a competent pump shop. That job isn't for the average wrench turner. As for being more expensive than the engine is worth, I'm with Doug, how dang cheap is this engine? I'd buy it. DB/DC RoosaMaster/Stanadyne Pump rebuilds in my shop typically run in the 800-1000 range when off a running engine.

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210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers!

Posted By: Tbone95
Date Posted: 26 Sep 2022 at 7:40am

How is the engine configured to shut off? A mechanical pull to shut off fuel, or a solenoid? I ask, because you say it is an engine hooked up to wood working equipment, so sounds like this is a shop built thing, so could be anything.

Posted By: Clay
Date Posted: 26 Sep 2022 at 8:22am

If the plastic gov ring is bad, you can replace it with a new plastic gov. However, there is a metal replacement which will LAST. A little more money but well worth the expense.

Also, replace the parachute packing and possibly the bushing. This packing keeps the diesel fuel from contaminating the crankcase.

Should you decide to rebuild your own pump, be sure to thoroughly READ the entire repair manual first!!!

Send the pump or do-it-yourself, take plenty of photos before removing anything. A good power wash is necessary. FOD is death to an injection system.

Remove the two screws from the cover on the side of the pump. Line up the lines in the pump. DO NOT MOVE THE CRANKSHAFT after the pump is aligned. This is necessary to help assist the proper location of the pump when reassembled.

A rebuilder will disassemble the entire pump and evaluate all the parts. They keep everything clean as an operating room. Their test equipment is quite expensive and sensitive. This is one of the reasons why the cost to rebuild is in the $800-$1,000 range.

If you have any doubt, send the pump to a good diesel injection pump rebuilder.

Posted By: injpumpEd
Date Posted: 26 Sep 2022 at 10:35am

The EID is no longer available for the DC pumps, which a 3400 engine may be equipped with. I really never recommend doing these yourself if you have to ask how they work. Now, many guys are experienced in them, but when someone says he is new to diesels, I highly recommend having the rebuild done. I've seen too many come in the have been "rebuilt" and you'd be surprised what some will do lol!

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210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers!

Posted By: RRF
Date Posted: 26 Sep 2022 at 3:21pm

The fuel filter has been replaced.

Posted By: RRF
Date Posted: 26 Sep 2022 at 3:24pm

I'm not sure how the engine is stopped. I'll have to ask the owner. I know he did tell me when the key is turned to on there is a click heard in the pump. That makes me think there is a solenoid in the pump.

Posted By: SteveM C/IL
Date Posted: 27 Sep 2022 at 9:30pm

If it has a solenoid ,they have been known to fail intermittingly. It would have a hot wire going to pump. Very obvious.

Posted By: gleaner1
Date Posted: 02 Oct 2022 at 7:57pm

Around here you can buy running L2’s for about 2K.
Pull the engine and haul the rest to the shredder and you’ll be ahead $$
To pay to rebuild any pump or one of those old motors at current shop rates is way more than that.
And yes the flex ring coming apart is the real issue plugging the check valve, but heck if you can get another couple years out of it for no $$$ why not.

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ALLIS CHALMERS "The color is orange"