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Old 05-10-2017   #8
Hog
 
Join Date: Jul 2010
Location: Woodstock, Ontario, Canada
Posts: 1,271
Default Re: New option for fuel pump replacement

Quote:
Originally Posted by 5ABI VT View Post
Glad to hear you figured it out was it a hesitation like mine ?

I'm also going to take everyone's advice on the stainless clamps and do that for sure . I will feel happy to find a broken plastic clip but not expecting it!!
Here's a clip I made last year and while I have had other symptoms of my clutch being worn in this case it can be felt and my rpms aren't slipping and rising which is a common clutch -slip symptom but I can feel and hear the delay in acceleration when hitting the next gear and it has made me suspect the pumps. I have changed plugs, wires, coils, injectors, o2 sensors and the map sensor. This video was taken after it all. Leads me back to the beggining ..

Around 14-15 second mark in the video.

https://youtu.be/bH7F59FKPEU
If you were able to view your WOT fuel pressure I'm thinking it would be ramping up during those periods when you are getting back on the throttle after you upshift.
As soon as you go WOT the ECM would be commanding very high pulsewidths, with all 16 injectors firing the fuel system is fighting to supply them with fuel and it takes a moment to get the fuel pressure back up.
Throwing some powershifts would eliminate your issue I'm guessing as the throttles remain open and there is no ramping up to full power. You would be looking for just under 52 psi at all times, IIRC the OEM regulator is set at 51.8psi for LT5.


A fuel pressure gauge taped to the windshield would tell the tale.


Cutting open fuel filters is a good idea as well. It doesn't take much to start to plug these high pressure fuel systems. I had a 66psi OEM GM system that woudnt rev over 4500rpm at WOT, I was surprised what was in the filter.






Mr Haibeck says that you require 51psi plus or minus 1 psi at WOT 3000-7000rpm. If you see less that 47psi of WOT fuel pressure, reduced power and knocking and possible codes can result. He agrees with talking her for a spin with the gauge taped to the windshield, he does make a good point to use a passenger though. The fuel pressure should snap up to 51 +/-psi (from around 43psi during normal driving when engine vacuum is high) when you stand on the throttle, then you know the FPR is working, or if you are at idle and you disconnect the vacuum supply to the FPR, you will see 51psi or so.
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