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Fuel Pressure Questions

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  #1  
Old 05-16-2008, 10:58 AM
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Default Fuel Pressure Questions

Ok, here it goes

When i start my truck up the fuel pressure reads around 14 PSI, however, starting late last fall into last winter my FP gauge needle has started to jump around slight between 1-2 PSI and also, when i WOT the truck now, my fuel pressure quickly drops to 9-10 PSI whereas last summer it stayed steady at 14-15 @ idle and never dropped below id say 13 @ WOT.

Is this caused by needing to put a new fuel filter in it (does WS need replacing at the same time?) or is my FP sending unit going south. When im on it at WOT my truck isnt very smooth in the upper RPM band either, it seems as though the truck is almost cutting out sporatically by 100-200 RPM, just enough to somewhat feel a drop in performance when in the truck. Would that indicate a dirty/clogged fuel filter or a VP problem.
 
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Old 05-16-2008, 11:31 AM
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Simple things first - do the filters on the FASS and or truck first. Record the differences. Next, check the pressure gauge with another one. If no change than your VP is going south on you.

Don't forget you can remove the screen on the inside of the tank as well. I haven't done that yet and may never do it but you can if you think it will make a difference.

You may also want to plumb the FASS the back of the existing cannister and run 3 filters like I do. Much better for the VP.
 
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Old 05-16-2008, 06:51 PM
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ok, the only other thing that kinda makes me wonder.....is when i went to drag race my truck a couple weeks ago i was gonna try one run with my MAP unplugged just to see if any diff. was there and when i got on my truck with the MAP unplugged my truck fell on its face multiple times, lost smoke and power then came back in. Would that also be an indication of pssible VP failure?
 
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Old 05-17-2008, 03:46 AM
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Are you running a draw tube? If not, the module pickup could be clogged up from debris or a bad load of fuel.

The 2000-2002 are some of the most restrictive modules. I hear of more pressure complaints, even after an install due to this reason. Just a thought.

Dave
 
  #5  
Old 05-17-2008, 10:12 AM
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Originally Posted by CumminsCrazed
ok, the only other thing that kinda makes me wonder.....is when i went to drag race my truck a couple weeks ago i was gonna try one run with my MAP unplugged just to see if any diff. was there and when i got on my truck with the MAP unplugged my truck fell on its face multiple times, lost smoke and power then came back in. Would that also be an indication of pssible VP failure?
Zach:

We've had this conversation before - unplugging your MAP is a not a BIGE mistake its a HUGE mistake as your trucks ECM needs that information to run properly. I don't care what others tell you but you are wasting fuel, money and causing major issues with your VP and ECM.

 
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Old 05-17-2008, 05:18 PM
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even to just run once down the track?

also, ive never heard of a draw tube for our trucks.....
 
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Old 05-17-2008, 08:53 PM
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Yes and yes.

Drop the tank, pull the guts there is a tube and a screen.
 
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Old 05-18-2008, 11:07 AM
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that sounds like a PITA !
 
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Old 05-18-2008, 11:30 AM
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It may be just as easy to pull the box off. It's personal
preference I guess.
 
  #10  
Old 05-18-2008, 11:53 AM
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It is far easier to drop the tank actually. The bolts in the bed are legally not allowed ot be reinstalled so unless you have more lying around run the tank low and put a chuck of plywood under use a jack and lower it down - really easy.
 


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