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Stock Fuel Pressure

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Old 06-09-2004, 12:13 PM
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Stock Fuel Pressure

What is it?
 
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Old 06-09-2004, 12:58 PM
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39psi with vaccumm line removed from regulator.

-Dale
 
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Old 06-09-2004, 01:07 PM
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Whats it at idle in drive with the vacuum line on?
 
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Old 06-09-2004, 01:32 PM
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That will vary depending on how much vaccumm you are pulling at idle... Depending on the cams used it can be all over the place...

It will definetly be less than 39psi though

Its best to just pop the vaccumm line off and check / adjust it.

-Dale
 
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Old 06-09-2004, 02:07 PM
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What will the pressure rise to when at full boost and WOT?
 
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Old 06-09-2004, 02:37 PM
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Originally posted by racetested
What will the pressure rise to when at full boost and WOT?
That depends upon the boost. A truck making 8lbs at full boost will have less pressure than a truck making 30lbs. Some trucks at WOT are not making full boost so at WOT so it is hard to say what the fuel pressure would be at WOT.
 
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Old 06-09-2004, 02:40 PM
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Originally posted by Dale-01L
That will vary depending on how much vaccumm you are pulling at idle... Depending on the cams used it can be all over the place...

It will definetly be less than 39psi though

Its best to just pop the vaccumm line off and check / adjust it.

-Dale
How are you suppose to adjust it? the Lightning's do not have an adjustable regulator.
 
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Old 06-09-2004, 02:51 PM
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Originally posted by easterisland
That depends upon the boost. A truck making 8lbs at full boost will have less pressure than a truck making 30lbs. Some trucks at WOT are not making full boost so at WOT so it is hard to say what the fuel pressure would be at WOT.
I may be thick headed here but I am under the impression that a forced induction motor increases fuel pressure as boost rises to supply enough fuel through the injectors. This would be done because less vacuum is present at the regulator and it stays shut to allow less fuel to return. Or does the L have the injector duty cylce change instead?
 
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Old 06-09-2004, 02:53 PM
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Originally posted by jarmstro
How are you suppose to adjust it? the Lightning's do not have an adjustable regulator.
You can't unless you go aftermarket fuel rails or 97 f150 rails, and get an adjustable regulator.
 
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Old 06-09-2004, 04:22 PM
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I don't know if how accurate my autometer is but thats the one I use at idle it is between 28-32 pis and WOT 50-54 all stock fuel system
Slick
 
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Old 06-09-2004, 04:31 PM
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Originally posted by racetested
I may be thick headed here but I am under the impression that a forced induction motor increases fuel pressure as boost rises to supply enough fuel through the injectors. This would be done because less vacuum is present at the regulator and it stays shut to allow less fuel to return. Or does the L have the injector duty cylce change instead?
The motor directly doesn't increase the fuel pressure the regulator increases the pressure usually 1:1(for every pound of boost pressure increases 1psi). The computer controls the duty cycle and that can be changed with a chip or reflash.
 
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Old 06-09-2004, 04:39 PM
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My 03L and my 01L both have / had fuel pressure gauges on them all the time once I installed my lower pulleys. The fuel systems where untouched (stock pumps, lines, injectors) and both trucks where making just shy of 15psi unless it was very cold out.

At idle you should be seeing 32/33psi, My current truck goes to about 54psi at WOT and stays there. Both trucks were holding A/F ratios in the low 11's BTW.

Bob
 
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Old 06-09-2004, 05:14 PM
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I am pushing 16lbs boost with my KB. Stock 42lb injectors, dual 255 pumps.

Idle = 38lbs

Light throttle = 40-42 lbs

WOT = 64 lbs

All on a lunar electric (not direct line) gauge.

D-Day

 
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Old 06-09-2004, 06:16 PM
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03 Lightning with a 4 lber

I show around 30 @ idle and around 50 at WOT

Also using autometer FP gauge
 
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Old 06-09-2004, 06:47 PM
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32 @ idle
52 @ WOT
cruising @ 70...around 36-38

Autometer electric

stock Fuel system..
 


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