HD5 fuel system
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Construction and other equipment
Forum Description: everything else with orange (or yellow) paint
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=137545
Printed Date: 02 May 2024 at 6:09am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: HD5 fuel system
Posted By: JC-WI
Subject: HD5 fuel system
Date Posted: 19 Apr 2017 at 8:59am
Yesterday, started the HD5 and it would run and then die... finally traced it to the rubber line coming up to the first fuel filter. It had gotten to just dripping for fuel flow. Also noticed the return line under the floor plate had about full turn twist in the steel line with a bunch of brass fittings ahead of it with a restricter in there just before connecting to the rubber flex hose going to the engine for the returning fuel... We replaced the main feed line rubber hose, and the final fuel filter, and cut out the twisted section of pipe on return line and slipped a section of rubber hose over the line and clamped it.
It now does not run out of fuel, but has the ability to fog anyone down wind.
Question - Do these engines have a restricter in the return line or are they suppose to be fully open? and should I remove the restrictor?
As for the fuel pressure gauge, it is not connected so do not know the PSI in the system though the gauge still reads 20PSI... Guess the gauge isn't functional anymore.
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He who says there is no evil has already deceived himself
The truth is the truth, sugar coated or not. Trawler II says, "Remember that."
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Replies:
Posted By: Ray54
Date Posted: 19 Apr 2017 at 11:38am
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The fuel restrictor was a original part of the fuel system. Been told they don't run without it,but never tried so cannot say for sure.
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Posted By: dadsdozerhd5b
Date Posted: 19 Apr 2017 at 4:47pm
check the air cleaner that it is not over full, has water in it or clogged. could be your fuel is old or filters still not clean. you mentioned you changed the final filter, what about the primary? they need a good flow of fuel and any remainder gets sent back to the tank. if it has not run in awhile it may just need to be run hard to clean it out or may be injectors clogging. is it just at idle or full throttle also? good luck.
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HD5B, HD5G, (2) FARMALL A's, CUB. DO IT RIGHT THE FIRST TIME, IGNORE THE LAUGHTER. FLANNEL IS ALWAYS IN STYLE.
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Posted By: wayneIA
Date Posted: 20 Apr 2017 at 12:40am
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The re-stricter is what gives you fuel pressure on your injectors to allow the engine to run. Without it the fuel would just free flow back to the tank and wouldn't give the injectors any pressure to operate. Mine smokes a lot when cold, once the engine warms up it goes away, or if you apply a load to the engine while it is cold the smoke will go away too (pulling a hydraulic lever and causing the system to hit relief pressure will do it). If I remember correctly the fuel system should have around 60 PSI when at full throttle. My crawler didn't have a fuel pressure gauge, so I just used an oil pressure gauge to be able to monitor it since I had to replace the rubber hose that came off the return orifice fitting and had to make a new orifice fitting and wanted to know I had the correct size hole drilled in it (the old line had odd-ball threads and had to replace the fittings to get to something standard).
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Posted By: JC-WI
Date Posted: 20 Apr 2017 at 2:24am
Thanks for replies.
I looked into the HD7, 10 and 14 book and see where it says fuel pressure to operate at 25-65 PSI at high idle... now it makes me believe that the twist in the steel return line was the restricter from factory, not somebody not watching what they were doing... was to uniform.
Book said the flow of fuel is used to cool the injectors, but still need the pressure to give the injectors adequate fuel charger.
Dadsdozer, the air cleaner was off and cleaned, the last owner left the bowl empty and did not put a gasket/ rubber washer and wing nut back on the pre-cleaner, thus had water in the bowl.
As for the filters, We had the primary filter out, and I would have put a new one in but parts store didn't have that filter listed in their books...
Worse, the filter that was in there had a wire handle on it to lift it out, and was rusty... Stuck my finger in the center hole and still had daylight, the holes for the wire handle were punched into the top plate and unfiltered fuel could flow through it there... made that way from the filter factory!
It is getting plenty of fuel now, starts and runs without wanting to stop. Had a good heavy load behind it and warmed the old crawler up to smoking off the old oil build up on the manifold. Still had smoke out of the ex pipe at all running speeds and under load, specially when over loaded. LOL...
Wayne, on the inlet line to first filter, I cut off the old rubber hose flush with the brass fittings and then bought hose large enough to fit over the old crimped sleeves and hose clamped it.
Next time I mess with this dozer, I will put a pressure gauge on to see what fuel psi it has.
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He who says there is no evil has already deceived himself
The truth is the truth, sugar coated or not. Trawler II says, "Remember that."
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Posted By: Coke-in-MN
Date Posted: 23 Apr 2017 at 1:32pm
I had to put a pulse restriction fitting in the fuel gauge line - as it would pulse gauge without the restricted diaphragm on original gauge - pressure is around 20 PSI running speed and it runs fine - return flow is cooling for the injector - as Detroit injection pressure is by the cam and rocker and not from fuel pump or injector pump like most diesels .
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Faith isn't a jump in the dark. It is a walk in the light. Faith is not guessing; it is knowing something.
"Challenges are what make life interesting; overcoming them is what makes life meaningful."
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Posted By: 1941jim
Date Posted: 09 May 2017 at 10:29pm
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Could have injectors leaking
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