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Old November 18th, 2017, 15:03
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Ecomike Ecomike is offline
NAXJA# 2091
Join Date: Dec 2006
Location: MilkyWay Galaxy
Posts: 15,113
Re: New fuel pump, new regulator, still has fuel pressure issue..

I hear OEM (if it exists) and Bosch are the only fuel pumps worth a damn for our jeeps. How bad is the bleed off? There is a reason the ECU cycles the pump on for 3 seconds during the start up/pre start process. It is to restore fuel pressure as some bleed down from say 30 to 20 in about 20-30 minutes is normal. If it ain't broke don't fix it. But it does need to hold some pressure to avoid vapor lock on hot restarts, and gas vapor in the injector feeds....

I had issues with my saturn recently, the FPR is in the external inline filter on them, LOL. Mine would drop to zero in under 10 seconds when the power went off when I found the problem. And the operating pressure was about 7 psi below spec while running. May have been that way for 10 years, LOL. It got bad enough to finally throw a lean code this year which was the second clue that sent me hunting, the first clue was bad gas mpgs this year... The FPR in the filter was bad.

Originally Posted by Intellect View Post
WOW that was informative, i did a quick read, but ill sit down and digest it later. But the gist is i more than likely have two issues at hand. Which is good..ish? To here LOL.

The pump taking a minute to turn on happens VERY VERY rarely. So ill adress the bleed off issue for now. Im putting an inline check valve in and reporting back.

I ran another test, with a fancy gauge set I bought. Right after the fuel filter. And BAM bleed off. Im guessing faulty pump, which im tired of replacing, so check valve it is!

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