fuel pressure test guage problems??

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Mar 20, 2006 | 01:36 PM

JR270

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Joined: Apr 2004

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From: Southwest, Virginia

fuel pressure test guage problems??

I was wanting to do the fuel pressure reg. mod on my '97 F-250. Thought that I would take a pressure check before and after to see if I had any improvement or how much improvement I got. Went to check the pressure at the sch. valve, and my test guage just bounced constantly when the truck was running (idle), from about 40-60 psi on the guauge. Thought that maybe I had guauge problems as it had not been used in a long time, so I borrowed a friends guage (identical guauge as mine), and it done the same thing, worse if the the rpm's on the truck is increased. Any suggestions?? Do I have a problem that I am unaware of or just checking the fuel pressure wrong? Does the deisel take a special guage? My guage said not to use on deisel engines but I thought since it maxed out at 100 psi and I should be running below that amount that my gauge should be fine. The truck runs great, starts easy, idles good. Thanks!!

Mar 20, 2006 | 02:08 PM

barebackjake

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Joined: Dec 2003

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From: STEPHENVILLE,TX!!!!!

thats about normal since its a mechanical cam actuated pump its gonna bounce so i take the average of what your getting.

i used to use a tire pressure gauge when i still had the oem fuel system on it. sounds like the one your using is fine.

Mar 20, 2006 | 05:50 PM

tjbeggs

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Joined: Apr 2004

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From: Silver Lake Dunes, MI

yep normal. the reason your gauge said not to use it on a diesel is they didn't want you to use it on engine that use an injection pump which have fuel pressure in the 1000's of psi range. but our injectors do all that work so they are just provided "low" pressure fuel