Pump shimming

[Ramsmoker]

If I have the potenceometer mod will shimming the fuel pump do anything or is this mod a duplicate.

[super_stroke]

what does the potenceometer mod do? and do you mean shimming the regulater? shimming the fpr (fuel pressure reg.) is supposed to increase the fuel pressure to the injectors from aroud 55psi to 60-65 psi. depending on what your truck likes. it makes the truck run smoother and quiter. plus make throttle response crisper.i havent done it yet but want to when it warms up.

[00powerstrokin]

how do you do that? what do you shim

[Ramsmoker]

I have the potenceometer now and I know it raises the fuel pressure. It has 2 ranges and a rotory dail to fine tune it. I bought mine from dfuser.com. What I wanted to know was the exact function of shimming the HPOP and if it is done to to raise the fuel. If thats all it is this electronic method is far better.

[super_stroke]

ok, i getchya. your talkin bout the 18k power module right? that basicaly tricks the comp. into thinkin oil pressure to the injectors is low. so it raises oil pressure, in turn it gives the fuel an added little "umph" into the cylinders. glorified version of the 10k mod. im not sure if that does the same thing as shimming the fpr or not. im thinkin not.

[Ramsmoker]

Well after the Christmas holiday i've had time to install my permanet under hood fuel pressure gauge. I don't know what the limits are but I started from the way mine was,57psi and worked my way up to 130psi where the fuel pump stalled. It didn't blow any fuses but I had to jumpstart it with a external wire. Past 100psi was very little change but from the standard upgrade at 70psi to 100psi is huge. I didn't leave it there except to test drive but boy was she smooth and quiet.

[LarryLuana]

I have owned my '99 for 6 years, and done a lot of upgrades, and changes to mine(see my sig for some), and will tell you what I know from experience.
I experimented with shimming the fuel regulater, and did the "bb" trick, and ended up with the longer stronger spring, and my fuel pressure went from 55 lbs to over 100 with the "bb" trick, and did not like the way it ran, and was told that was too much fuel pressue, and could cause damage so went with the longer spring, and got my fuel pressure at 75 lbs, and has been that way since aobut 4 years ago without any problems, and truck runs great.
As far as the 10K mod as they call it for the pressure of the HPOP I tried a few different resistors, and found the best setting was with a 5.6K ohm resistor, and kept the pressures in the safe range. On the dyno I had a gain of 45 horsepower, and lots smore smoke out the exhaust . That has been one of the cheapest noticable improvements($10) I have. Now you have to use a relay tied into your throttle sensure under your throttle pedal as the truck will idle very rough, and load up on you like running too rich or use an on/off switch so you can turn it on, and off when you want that little extra like I do when I turn on my propane as the boost also goes up, and drives my propane harder for more power.
Hope this helps some.

Larry

[overl0rd]

65 PSI is International's spec for the pressure, Ford says 45-60 is OK. I think optimum pressure is around 70.

I ran the 5.6K for a while but scrapped it in favor of a potentiometer. I got a 0-10K pot and ran a 3.9K resistor inline with it so it doesn't damage anything (I don't know if too low a resistance would, dfuser says no but I'm still skeptical) so effectively it's adjustable from 3.9-13.9K.

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Last edited by overl0rd : 01-07-2006 at 09:49 PM.

[DieselDan]

So how exactly is the regulator shimmed or bigger spring put in??

[LarryLuana]

On the right side of the fuel filter canister(looking at it from the front when you stand on the bumper or ladder) the fuel line(metal tubing) goes into the regulator which is held on with 2 bolts. Take this off carefully, and there is a piston inside with a spring, and just change the spring, and put back together, and check for leaks.
I am sure someone can give you a better explanation but it was 4 years ago or so when I did this so if you need bettee instructions just ask, and am sure some will chime in with help.
Since I put mine in never had a problem(100,000 miles), and did notice it was more responsive, and ran much better.
Sorry I cannot tell you where to get the spring but it was made for just this purpose, and was one of the aftermarket dealers but don't remember who
Hope I have been some help.

Larry