Moditis? Or what?
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Registered User
Joined: May 2006
Posts: 5,617
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From: Pacific NW, B'ham, Kalispell MT
Moditis? Or what?
So I got the FASS installed and noticed my truck seems just a tiny bit peppier upon acceleration....
Does higher fuel pressure improve the injection pumps efficiency enough to feel a little, or is it just in my head?
Does higher fuel pressure improve the injection pumps efficiency enough to feel a little, or is it just in my head?
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Joined: Jan 2003
Posts: 4,179
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From: The "real" Northern CA
Sorry SIXSLUG but if you noticed a performance increase upon installing a FASS then your VP may not be very healthy. This isnt to uncommon for guys who install an Airdog, FASS, Raptor, Fuel Boss, etc. while still running the factory VP, and chalked up as just in your head. But really this is because the old OEM timing piston and sleeve wears over time as the OEM lift pumps dont supply the adequate fuel pressures, and also because the factory VP's used some inferior internal components like the brass timing piston sleeve. So as the timing piston and sleeve wear, it becomes harder to achieve optimal fuel timing and performance goes down.....usually unnoticed. Then when you supply the 15-20 psi of fuel pressure with a good fuel pump, now the low pressure side of the VP is carrying more weight and the timing piston achieves better fuel timing. In saying all that, your VP may last for quite awhile so dont run out and get one just because of what I said. 
Thread Starter
Registered User
Joined: May 2006
Posts: 5,617
Likes: 168
From: Pacific NW, B'ham, Kalispell MT
That is kind of what I was worried about!
The intank pump was supplying 8 psi and down to 1 or less at full throttle, which I don't often use, for the past few months.
I now have 16-17 at idle and no less than 9 at WOT, so the FASS is doing its job.
I dreaded dropping the fuel tank, but it was a piece of fruit cake to do, no fun, but figured i would save a lot of time over removing my tool boxes/canopy and rack from the bed to go that route...
A stock fuel module with no pump and it was ready to go back in...
We'll keep an eye on the vp for now.
Thanks!
The intank pump was supplying 8 psi and down to 1 or less at full throttle, which I don't often use, for the past few months.
I now have 16-17 at idle and no less than 9 at WOT, so the FASS is doing its job.
I dreaded dropping the fuel tank, but it was a piece of fruit cake to do, no fun, but figured i would save a lot of time over removing my tool boxes/canopy and rack from the bed to go that route...
A stock fuel module with no pump and it was ready to go back in...
We'll keep an eye on the vp for now.
Thanks!