Construction and other equipment - fuel pressure question

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fuel pressure question

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=37692
Printed Date: 25 Jun 2025 at 12:36pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: fuel pressure question

Posted By: giz's hd-6ep
Subject: fuel pressure question
Date Posted: 21 Sep 2011 at 7:04pm

hello all, ran dozer for about 45 minutes other day and fuel pressure was on zero at idle when i rev engine it goes to almost 10 lbs .it runs good and smooth no misses but won't start without a shot of either even when it's warmed up .it hasn't been run in about 6 years ,wondering if it needs to be run a while to magically fix itself lol or is fuel pump shot .any adjustments i can do for more pressure ?? what should pressure be? also anyone have any issues with the low sulfur fuel does the additive work.

Replies:

Posted By: Coke-in-MN
Date Posted: 21 Sep 2011 at 7:35pm

use a trial gauge to be sure the one on tractor is good. be sure filters are clean and no restriction on intake side of pump. Starting can be a pump problem or a compression problem.

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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."

Posted By: giz's hd-6ep
Date Posted: 21 Sep 2011 at 7:48pm

yea was thinking about using different gauge after i posted what should pressure be ?

Posted By: CAL(KS)
Date Posted: 21 Sep 2011 at 9:31pm

check it out, low fuel pressure will ruin your injection pump. I have no idea on your machine but my HD16 is like 40-60 lbs fuel pressure per service manual.

Posted By: Mactractor
Date Posted: 21 Sep 2011 at 10:10pm

If engine has good compression, the pump is likely to be worn to where fuel shops describe them as not having enough start up pressure. The wear usually results from fuel not being kept clean enough. The American Bocsh PSB pumps are very sensitive to dirty fuel just like injectors in two cycle Detroits - the very reason they both use the same fine filtration. If your pump has to come off, find a fuel shop with experience in rebuilding the hydraulic heads on those pumps. They are not to be handled by any fuel shop that has no experience with them. Mac