Engine/Transmission (1998.5 - 2002) Fuel pressure regulator questions

[Wyatt 1]

Does anyone have any pictures that has to do with installation of a fuel pressure regulator? Also I have read about relay or something of this nature being installed in conjunction with the FASS, I will be installing one very soon and would like to do it right. Thanks Henry,

 

[rweis]

I put a fuel bypass regulator on mine. Reasons:



1. I have the OEM lp on the frame and did not want it to run against a head pressure when the VP demand was low.



2. I wanted the Lp to run as safely, smoothly, freely as possible using as little current as possible and not to stress the motor to pump nylon connection.



3. Recently learned that the lp can cavitate when low demand and the lp is running "normally". Bypass assures a constant flow of fuel THROUGH the lp.



4. Keeps the "flipping" internal check valve ball SEATED!!!!!!!!!!!!!!!!! A major source of lp failure is check valve not reseating correctly, breaking through the seat, not sealing, damaging the seat and therefore leaking through the seat.



5. Allows me to set the psi the VP sees at the inlet to what I think is an optimum 12-14 psi (see DTT threads on RASP bypass psi settings). I set mine to 12 psi. (The lp check valve opens at 14 psi. )



6. Bypasses excess fuel back to the tank vent and fuel is constantly recycled through RACOR 690T filter to keep fuel clean.



7. Because I thought it was a good idea. Probably the most important point.



Bob Weis



Sequence: Tank, RACOR 690T (in bed pocket driver's side), lp (on frame), Mallory 4307M (bypass regulator) (on frame), fp gauge (right at OEM ff inlet), OEM ff, fp gauge (right at VP inlet), VP

 

[Wyatt 1]

Thanks for the rundown, I was under the assumption the regulator had to be in the engine compartment for some reason??? On the frame, you are talking about close to the pump and away from the engine compartment, correct? Makes sense, and you are running two guages, one at the OEM ff, what, where is that?

 

[rweis]

I have a 2002 and the stock (OEM) fuel filter is the fuel filter up on the engine driver's side (where the lp used to be). I take one fuel psi reading before that filter. I take the other fuel psi reading just before the VP. That way I can see the difference of fuel psi going into the stock filter and on the other side of the stock filter and that will tell me if the stock filter is plugged up and needs to be changed. Plus I see exactely what the VP is seeing at the fuel inlet to the VP.



One thing I did find about reading fuel psi at the VP inlet is the internal pumps of the VP create a very high frequency pulsing to the gauge at the VP inlet. I tried an 18" snubber line made of AN-4 and that sensor only lasted about 4 months before failure. I then tried a needle valve on that 18" snubber line and that sensor failed in about another 8 months. The sensors were the Westach solid state sensors which Westach replaced without any hassle at all. Then I tried an 120" wrap of AN-6 that wraps irregularly around the air horn then the sensor. The thought here was I would try to totally dampen the VP pulse through excessive length, irregular turns, and shear volume (120" x 3/8" dia ~ 13. 25 cu "). So far the excessive length has worked.



I also think having the bypass regulator which has a port back to the tank vent line allows any VP pressure pulse that gets back through the stock filter a place to go. With the bypass regulator the fuel system is no longer a closed system but has a vent back to the tank.



Just some thoughts,



Bob Weis

 

[Wyatt 1]

OH now I see says the blind man. I knew it had to do with the filter, just one of those days, brain fart!! So basically the first guage and second guage together work sort of like a filter minder, for your fuel filter, while also providing the necessary info for the VP which doesnt like low fuel pressure. Does it matter where you mount the regulator, before or after the filter?

 

[rweis]

I would not think it would matter where you mounted the regulator.



I mounted mine back on the frame because it was easier to get the return line back to the tank. I had more room back on the frame and was not fighting for space to work in like I thought I would have to do if the regulator was up in the engine compartment.



Yes the two fp gauges are like a filter minder.



Bob Weis

 

[Wyatt 1]

I will look and see the best place for me but it helps when you know what works and for good reason, I appreciate your patience Bob, thanks for the help, I will start my install of the twins and everything else in about a week, I will try to post some pics, have a good day

 

[rweis]

Twins, that should be fun!



Bob Weis