Fueling & Injection Fuel Pumps | Injectors | Rails | Regulators | Tanks

Low pressure at WOT

Old Aug 26, 2011 | 11:57 PM
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Default Low pressure at WOT

I know I have an issue with the fuel pressure. I just need opinions as to where to start looking.

I replaced my stock pump with a Racetronix unit and the idle pressure is at 38psi. This is roughly the same as was with the stock unit, this is the reason I replaced it.

My concern is that as of recently, I went WOT a couple of times and the pressure drops to nearly 0-5 psi. i am not too familiar with fuel systems, so where to you guys recommend I start looking?
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Old Aug 27, 2011 | 07:42 AM
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You did change the fuel filter, right?? The voltage at the pump is correct, right?
If so, then take a look at the in-tank pump plumbing...
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Old Aug 27, 2011 | 11:08 AM
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I'm doing the fuel filter today and will verify the voltage........should be at 12, correct?

Thanks Old Geez......any other suggestions?
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Old Aug 27, 2011 | 03:09 PM
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Check the voltage at the alt..Pump should be not more than 1/2 volt less. You do have it hot wired, right??
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Old Aug 28, 2011 | 12:52 AM
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Filter is swapped and it helped some. Still loses between 15-20 psi under wot, however not as bad as before.

Didn't get a chance to check the voltage since I do not have a volt meter. I will check that in the morning. The pump is wired with the racetronix hotwire kit to the alternator. I wouldn't be surprised if the alternator has something to do with my problems since I can sometimes see the just under the half way point on the gauge.
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Old Sep 3, 2011 | 04:55 PM
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FOUND THE PROBLEM!!!!

After a TON of research, I thought I had the problem narrowed down to the fuel pressure regulator. I rushed down to the dealer to grab a new one, however they are $65 and I second guessed myself because I wasn't 100% sure if this would solve the issue.

Came back home and I pulled the fuel assembly out (thank god for the access panel) and double checked all of the connections. Everything seemed good except the line that keeps the bucket full seemed loose. I pulled everything apart and sure enough, it came loose from the bottom of the bucket that keeps it full.

Long story short the pump was sucking most of the fuel from the bucket at WOT which explains the pressure drop. Here is a picture of the connector I am talking about.

I hope this info is helpful to others because I was puzzled for a while.
Attached Thumbnails Low pressure at WOT-img_1612.jpg  
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