vanwill52

I tend to post only on things with which I have PERSONAL EXPERIENCE (because I feel the spectre of my old friend Bill D breathing over my shoulder?) I can say that I had a problem with algae in my fuel, even though I only park over extended periods with a full tank. I built my own fuel polishing setup. It removed quite a bit of contaminant. That was two years before the FASS installation. As I reported, in a short time after the FASS installation, I had to change a PRIMARY filter (the one on the FASS manifold). It had the same appearance as the problem I had experienced before "polishing" the fuel. I spent quite a bit of effort and money on my homemade fuel polishing rig, and it APPEARED to work...it trapped a lot of "black slime". After that, I thought I was home free. I used biocides for the fuel regularly. And yet, when I installed the FASS system, it clogged up a primary filter with the same "black slime" in a short time although I thought I had totally removed the contaminants with my fuel polishing rig. What I've taken away from the experience is that a fuel pressure gage located at the OUTLET of the secondary filter (the last one before the CAPS pump) is worthwhile even if you never install any sort of auxiliary fuel pump (FASS, Air Dog, etc.). What you get from the fuel pressure gage is an "early warning" that your filters are becoming clogged...BEFORE you starve the CAPS pump, experience power loss, and have to pull off the road. I've always changed my filters by date-in-service. Now, I only replace them when they show EARLY indications of needing attention. I like the fuel polishing capability of the FASS Titanium system enough to pay the premium for it compared to the FASS pump-only system. But I have neither quarrel nor condescention for those who choose the pump-only configuration. Either one will forestall an early demise to your CAPS pump. As I always try to say, YMMV, and it's your coach...do as you see fit. Thanks for this great group that is moving steadily to its beginnings, when it told you HOW TO do stuff, instead of YOU NEED AN EXPERT to do it for you. Van

Dave? I think the difference is that the model(s) that does not have the filters and manifold has an internal bypassing pressure relief valve. It recirculates the excess fuel from the output of the pump back to the input of the pump internally. At least I think that is what I read when I was deciding which pump model to buy. There is nothing wrong with doing it that way. You still have positive pressure at the CAPS pump inlet and will never starve it. You will also be pushing more fuel through the CAPS pump and back to the tank through the existing return line in the lift pump manifold. You just won't have "full-time fuel polishing (filtration)". The amount of fuel that the models with fuel filters is constantly filtering is quite large. In my case, it's over 90 GPH. I noticed that with all new filters when I installed the system, it took only a short time before the primary filter clogged enough to drop the pressure at the CAPS pump from 15 PSI to 10 PSI. If you have a remote fuel pressure gage, it is a handly indicator of when filters need changing.

I had the same experience of much faster engine turnover using a gear-reduction Denso to replace the Delco on an ISC-350 in a 2000 Dynasty. Measured the current and it was much lower inrush with the Denso and also significantly lower while continuously turning over. Spins over like a Honda. Will start in freezing weather without block heater and not even waiting for the "Wait to Start" lamp to extinguish, although that was only a test--I always wait for the "Wait to Start" lamp to extinguish. I think there is also a gear-reduction starter from Delco, but I know nothing about it.

Jim, I used the same supply line from the main fuel tank that fed into the original primary filter. IIRC, I used the same line originally going from the outlet of the primary filter to the lift pump (look it up, the connections are not intuitive) to plug into the outlet of the FASS pump. I know I did not have to have any additional hoses made. I only removed and discarded some lines from the original lift pump. So, the only line I had to ADD was the long 1/2" return line from the FASS pump to the tank. My tank had an unused tapping in it...probably for an Aqua-Hot option, which I do not have. I used that for my return line connection to the fuel tank. I'm sure you could tee into any other fitting, being sure that there was not any significant restriction. Let me know if any of this is not clear. Van

Jim, I'm going to try to attach some pix of the fuse block installation. I got the battery+ from the RRB (rear run bay). It feeds a continuous duty contactor that is triggered by an on-with-ignition source in the terminal block above the contactor. The diode is there as spike insurance, since some of the ignition terminals are used as inputs to the ECM. The output of the contactor (2 AWG) goes to the rear of the RRB and into the engine compartment and feeds a Blue Sea 10-circuit fuse panel. I've used the fuse panel to supply any number of loads, including my EGT gage, Fuel Pressure gage, FASS pump, and my externally mounted transmission cooler fan. Walt Heathcock gave me the trans cooler. I think it was from a Diplomat. I wanted to get the transmission cooling out of the engine radiator before my trip to Alaska in 2016. To accommodate having (8) T-145 size batteries (NOT T-105, the normal choice) I had to move my engine battery from the normal location in the battery bay. It was an 8D and too large to wrestle into the location shown in the last pix, so I put two 12V truck batteries in parallel behind the engine radiator. My house battery bank is approximately 1000 AH and is great for dry camping. I always thought that "sacred cow" about never mixing battery types had no technical validity. My mixed set has performed well for five years now. You can also see the Blue Sea ML-ACR installation between the battery trays and RRB. That was a great addition. It replaced the Solid State Isolator, the Lambert Charger, and the Big Boy. Now, if I ever chose to install a higher capacity alternator, it can be any garden-variety one--doesn't need to be DUVAC. Van

I'm not sure how well you understand 12VDC electrics, but adding a multiple fuse block SWITCHED ON BY IGNITION in your rear engine area will prove to be useful many times. HOWEVER, do not just connect to an ignition key signal and try to power whatever from that signal. Use that signal to power a contactor (relay) to power a fuse block that you install that can then be used for virtually anything. Let the contactor connect to a major battery +12VDC post and then power your fuse block from that contactor. I've installed such a fuse block and have since used it for my FASS pump, my external Allison cooler fan, my EGT gage, my fuel pressure gage, etc. It is invaluable IMHO to have a multiple fuse block available in the rear engine compartment to power any number of devices that you only want to be powered only when the ignition key is "ON". BTW, I have little experience with the BIRD system, but compared to the Blue Sea ML-ACR (first introduced to our members by electric/electronic/WiFi/electronic shitter) expert Paul Whittle, the BIRD is an unnecesarily complicated system that the ML-ACR condensed into one SIMPLE inexpensive device, which has a no-BS lifetime warranty, is easily installed, easily UNDERSTOOD, and works WITHOUT GLICTHCES. You mention a "FASS relay". I'm not sure I that was included in my Titanium FASS installation, but I understood it was a high-amperage device and required a supply capable of supplying its needs. My installation has been problem-free, and with a cockpit-mounted fuel pressure gage measuring fuel pressure at the INLET TO THE CAPS PUMP, I have an "early warning" indicator of when I need to replace fuel filters. Although I do not strongly advocate the FASS brand over any other brand, I like the feature of constantly filtering a large volume of the contents of my fuel tank...and a cockpit-mounted fuel pressure gage that alerts me to a filter becoming clogged long before it causes me to pull off the road at reduced power;

As David said, many are not dimmable. Internal voltage regulation circuitry causes them to dim only slightly before beginning to flicker and then turning completely off.

When I removed my valves to replace them, the piping from either side collapsed inward. It had to be spread apart to get the valve to slide in without disturbing the seals. After several tries, I made a "spreader" from threaded rod and wood to hold it spread apart. Also, on my 2000 Dynasty, pulling either valve to dump the tank put enough strain on the pipes to cause them to move quite a bit. Thinking this might one day become a problem, I added braces to the two valve assemblies to keep them firmly in place.

Jim, although FASS has filters with their brand on them, the website has a cross-reference to common filter types. And you will only be changing them when they actually need it, if you have a pressure gage to warn you. JD, perhaps I was not clear, but the ball valve I installed on the original fuel line from the tank, the one that normally went to the inlet of the PRIMARY filter. If you install the ball valve anywhere else, fuel will still drain back to the tank when you change filters. Van

Perhaps the FASS folks have changed their installation instructions since my installation. What you have posted is different than what I had with my Titanium 095 unit, which included two filters and the pump mounted to a manifold. I ended up with THREE fuel filters--TWO on the FASS unit plus my existing secondary filter. My secondary (final) fuel filter is now a 2 micron one. Why not use as fine a filter as possible? Two micron filters might have over-burdened the original CAPS inlet-section gear pump's ability to suck fuel from a tank 25 feet away. But now there is positive pressure there at all times. I eliminated the original PRIMARY filter and mounted the FASS pump in its location. Someone may correct me if I'm wrong, but my understanding was that the OEM return line from the CAPS pump through the manifold atop the lift pump returned a modest amount of fuel to the tank from the CAPS pump. That small line stays intact after the FASS installation, but is not capable of handling the much larger flow from the FASS pump, at least without triggering some kind of fault code from the ECM. I questioned the need for the separate dedicated return line for the FASS pump, but a call to tech support and a conversation with a savvy tech convinced me it was required. I think the FASS pump is a simple high-capacity gear pump with a pressure relief valve to divert excess flow back to the fuel tank. If you let the FASS pump exhaust its excess fuel through the existing return line, you would cause the pressure in that line to increase, decreasing the pressure differential from inlet-to-outlet of the CAPS pump...the very pressure that you are trying to INCREASE. Better to let the CAPS pump stay pressurized at the 15 PSI of the FASS pump. Also, if you run a separate dedicated return line from the FASS pump to your fuel tank, you can measure the pressure at the inlet of the CAPS pump as a reliable indicator of when your filters are becoming clogged before they actually begin starving the CAPS pump. I had to drill and tap a 1/8 NPT hole in the top of my secondary filter housing to mount the gage sending unit. Many coaches already have a tapping in the location that merely needs to have an existing plug removed. And let me repeat that I installed the FASS pump as an "insurance policy" for my CAPS pump, and not for any performance reason. Raising your CAPS inlet pressure does nothing to increase the HP or torque of your engine, any more than raising boost pressure will. I did plan to (and later did) install an Ag Solutions "chip" and thought the FASS pump would be a good idea for an OEM installation that might already be straining the capabilities of the CAPS pump's original delivery system. I would suggest that you use this opportunity to add a quarter-turn ball valve to the INLET of your FASS pump. You can close this valve when changing filters, and even if you are on a hill nose-down, all the fuel will not drain back into the tank. Van JD, sorry, but I just noticed you are installing the "pump-only" version of the FASS system. There must be some internal bypass fluid circuitry on that model and perhaps it does not need a dedicated return line. As long as you maintain a positive pressure to the inlet of the CAPS pump, you have accomplished the objective of trying to get max life out of your CAPS pump. In the pump-only version of FASS, they must be expecting to exhaust all unused fuel through the original return line. Van

Ken, My choice between the FASS and competing systems was based purely on the fact that the "always on" FASS pump bypasses a great deal of fuel through the filters constantly. YES, it does require a dedicated return hose to the tank. NO, you cannot use the existing return line from the lift pump. It's like having a fuel filtration system operating fulltime. I had a serious problem with algae in my fuel tank several years ago and even put together a homemade "fuel polishing" system to clean my tank. It worked, and got me going again. I installed the FASS system to help permanently keep that algae and other contaminants from causing future problems. And initially I changed the TWO primary filters TWICE very soon after installing the FASS system. Since having the algae problem, I always cut open my fuel filters to see what they have "trapped". I'm glad to see "bikedavem" (sorry, don't know your name) commenting that adding the FASS (or any other) system made no perceptible difference in performance. Any perceptions of increased performance are purely between the user's ears (kind of like curing wandering with different shocks). But you are POSSIBLY increasing the life of your CAPS pump by pumping through it under pressure a great deal more fuel than it needs, thereby giving it uninterrupted lubrication and cooling. Another benefit of the FASS (or other brand) system is that IFF you install a fuel pressure gage at the inlet to the CAPS pump (OUTLET of the secondary fuel filter), you will have an "early warning" system to let you know a filter will soon need changing. I no longer change filters based on time or mileage. I replace them when the pressure at the CAPS pump falls from 15 PSI to 10 PSI or lower. Van

I always love it when someone is told, "Oh, you can't do that yourself! You need an expert to do that!"...and they do a bang-up better job than they could have paid for ANYWHERE. How many times have so many of us turned to a so-called expert for advice? And how many times have you realized only a few minutes into the conversation that YOU could be advising THEM, instead of the other way around? I think many of our forum members have great depth of knowledge in any number of areas...and perhaps more importantly, a "can do" attitude. Recently, Paul Whittle (aka "Pooper Paul" or "Shitter Whittle"...the electronic toilet circuit board man) was at my house and discovered a gray-water leakage problem was due to a FAULTY PVC fitting in an ungodly place to get to, much less repair. Long story short, Paul made a first-rate repair to a problem that appeared almost impossible to fix. We both agreed that either of us would have been willing to spend whatever it cost to have SOMEONE ELSE fix this knotty problem. But, "who ya gonna call?" Some things can only be repaired properly by an owner who is MOTIVATED to do a first-class job. Years ago, this was the "go to" forum for DIY. It seemed to slip towards a forum that told you every reason you should NOT try to repair something yourself, including why it was too dangerous. I never disregard safety, but I'm glad to see more and more posts with the "can do" attitude returning. Jon, I look forward to your future posts. Kudos!

I stand corrected about using the bleeder valve to fill a tank above the level of the supply tank. Yes, slightly cracking the bleeder on the tank to be filled would surely work. As far as pouring liquid propane at atmospheric pressure, I've only tried discharging it (from the LIQUID port) into an open dish, and it evaporated as quickly as it hit the pan. I could never accumulate liquid. Perhaps if I had used another container with a small neck, I would have gotten different result. Thanks for your input.

A common misconception about propane tanks (and aerosol paint "rattle-cans") is that the liquid is injected into the container and then enough gaseous vapor is pumped in to provide the "pressure" to expel the liquid until the container is empty. Propane is "liquified petroleum gas--LPG". Liquid propane cannot exist AS A LIQUID at atmospheric pressure, even if the temps are near 0*F--it will "flash off" just as Freon will at atmospheric pressure. The pressure in an LP gas tank varies with temperature, but at temps you might normally encounter, is in the range of 140-180 PSI. The liquid propane is not "injected" into the tank and then some gaseous compressor raises the pressure in the tank to some acceptable level. The pressure in the tank is due to the "vapor pressure" of the liquid propane. The vapor pressure is the pressure that will keep the gaseous propane in a liquid form at any given temperature. It may be a difficult concept to understand, but if you were able to "pour" a small amount of liquid propane into a large container (not possible) and then cap it, the pressure inside the container would rise to the vapor pressure of the liquid propane at that given temperature (as long as any propane in liquid form still existed). If you were then able to "pour" more liquid propane into that container without letting any pressure escape, the pressure in the container would not rise...it would remain the same. No matter whether a 50 gallon container has 2 gallons of liquid propane or 40 gallons of liquid propane, the internal pressure of the tank will remain the same. That is why you cannot gage how much propane remains in a tank by checking the pressure. The pressure is the same when it is totally full as when there is only a small amount of liquid propane left. The internal pressure is not the result of any gaseous fluid that has been PUMPED into the tank...it is the pressure resulting from the liquid inside wanting to evaporate until it reaches the pressure at which it can no longer evaporate, and must remain as a liquid. Perhaps to make this easier to understand, consider the propane tank that I filled my forklift tanks at my business. Our forklift tanks were about 5 gallon capacity. We filled them from a 250 gallon tank ON STILTS in our parking lot. We did not need a pump, as you might see when you have a grill tank refilled at a propane retailer. Why? Because the pressure in our 250 gallon tank (nearly full or nearly empty) was the same as in our (nearly full or nearly empty) 5 gallon) forklift tanks. We would just hook up the large diameter hose from the 250 gallon tank to the fitting on the 5 gallon forklift tank. The forklift tank is marked as to what it should weigh when 80% full (legal limit). You would place the forklift tank on weight scales, open the valve on the forklift tank, open the 250 gallon tank valve, and the liquid propane would flow by GRAVITY into the 5 gallon tank. All the while, the pressure in BOTH the 250 gallon tank and the 5 gallon tank are EQUAL. GRAVITY lets the liquid propane flow from the higher tank to the lower one. So, you might ask, why does the propane dealer always "pump" the propane into your tank? Because it is much faster than waiting for the slow flow of gravity, or in some cases, because the propane dealer's tank is below the platform at which he is dispensing, so gravity fill won't work. Perhaps now you understand why you cannot dispense propane from a 20# tank SITTING BELOW your RV tank, no matter how you connect them. The pressures in both tanks are equal, and you can't get the liquid propane to "run uphill". On the other hand, if you held the 20# tank ABOVE your RV tank, and got the SIPHON action going, you could slowly transfer the liquid from your 20# tank to your RV tank. I tried to make this as simple as possible. I hope it's understandable. Most mechanical engineers understand it without question, but it's sometimes hard to grasp for "normal" folks. 😁

I wanted to increase the AH capacity of my coach battery bank. I had four nearly-new T-145 (NO, not T-105) Trojans in my lower battery tray. A friend offered me his four nearly new Interstates in the same size as mine. I had an 8D in the upper tray for the engine and chassis. I welded up a new tray to hold two Group 31 batteries of approximately 950 CCA each behind the side radiator. I then made a new tray to accomodate the extra height of the Interstate T-145 equivalents to be the upper tray in my original battery compartment. (Hmmmm...wonder if someone will give us the "ad nauseum" lecture about mixing battery types/ages/capacities? I've run this setup for over five years (60K miles), including a trip to Alaska.) Even with a residential fridge and a propane furnace with 12VDC blower, I can survive an overnight of 30*F and have 65% battery capacity left in the morning. That resulted in approximately 1000 AH of coach batteries and over 1800 CCA for the engine. I have lots of 4/0 cable, a hydraulic crimper, and a large assortment of battery lug terminals. I ran the shortest possible 4/0 cables to the starter. Previously, I never had a case when the engine would not start...but it always seemed to me that it just BARELY started...turned over too slowly and too long in cold weather. After the new battery arrangement, a Denso gear-reduction starter, and the Blue Sea ML-ACR battery management device, the old ISC spins over like a Honda. It will start in 25*F weather without block heater or waiting for the "Wait to Start" light to go out. (Hmmmm...wonder if someone is going to give us a lecture about the grave harm done by starting the engine without waiting for the "Wait to Start" light to extinguish. 😄) I did not use AGM batteries for the engine/chassis batteries, but I did choose "Maintenance-Free" batteries and they are certainly nice in this installation. I could barely wrestle the old 8D into its tray when I was 66, six years ago. I would not like to try it again at 72. I think even if someone were not planning to relocate the engine/chassis battery, it would be worthwhile to replace the 8D with two Group 31 (or similar) batteries

I hope you do not have one like Tom Moore's 2011? Camelot. Hard to believe, but the side framing of the entry door was narrower than the step cover, as if the side framing was added AFTER the step cover was installed. I removed that one the only way possible--sawed off rivets and attachment points to remove it piece-by-piece. I machined new attachment points and made two-piece scissor arms to allow the step cover to be reinstalled by assembling it into the recess for the step cover. IIRC (if I remember correctly), I also made the front and rear cross supports to be disassembled and reassembled two pieces. BTW, Tom's problem was that his motor had burned out. The replacement motor from Grainger was inexpensive, but the process of replacing it was a booger. If your motor is still running you obviously have another problem. Based on my experience, I would think the gimpy setscrew on the motor shaft or the equally gimpy way the larger gearbelt pully was secured to the Acme would be the culprit. As long as removing the unit is not a nightmare like on Tom Moore's Camelot, the repair is not difficult or expensive. For the life of me, I'll never understand why Monaco replaced the super-simple air cylinder actuator with that Rube Goldberg, multi-part, Acme screw apparatus.

No offense taken. I do think the "Increase Power in ISC" thread has gone off the rails. Perhaps there needs to be yet another thread started debating this brake light issue.

This is one of those hotly contested subjects that has been discussed to death. Just as many knowledgeable people choose one way or the other. This thread can go on and on, or everyone can agree to disagree and move on. Otherwise, we'll hear all those explanations we've all heard dozens of times. Let it rest. Waste of time.

There are literally hundreds of threads on many forums about the headaches of "replacing" rather than "rebuilding" your existing alternator. Yours on your 1999 coach is a DUVAC style which must have a battery "feedback" terminal so that it can read the voltage "at the battery" rather than "at the alternator output". The solid state isolator causes voltage AT THE GENERATOR to be at least 0.7 volts too low to properly charge the batteries. Either have your alternator rebuilt or use the temporary methods suggested to get you home safely until you can take the alternator to a qualified repair shop. Install any replacement alternator without that remote voltage-sensing feature and your batteries will never charge completely. If you convert your coach to use the Blue Sea ML-ACR, you will eliminate the SSI, the Lambert auxiliary charger, and the Big Boy (battery boost) solenoid. Search this site for the several threads on making the conversion to the ML-ACR. Once installed, any garden-variety alternator can be substituted for your DUVAC model.

There have been at least two different manufacturers of the hydraulic systems for the generator slide. Mine is HWH on my 2000 Dynasty 36. It does not have external valves to change directions. It was simply a gear pump and two contactors mounted to the motor reversed the polarity to the motor to drive it in or out. There are no external valves. I don't think that system has ever had the problem with "creep-out". I have repaired the leaking cylinder with $15 worth of seals. If you have the system with the lockout valve, if the piston seal itself was leaking (internal leakage from one side of the cylinder to the other) might it still creep out even if the lockout valve was functioning properly? I have no experience with that model. If you have the system with a lockout valve, and it is a very expensive part, I would think you could insert an inexpensive solenoid valve in the "out" line to sidestep your problem. Power the added solenoid valve from the motor of the hydraulic pump. Just speculation--I've never done it.

Disclaimer: I have not done this, nor have I ever contemplated it. (Shades of Bill D looking over my shoulder and asking, "You've got personal experience with that, right? Otherwise you would not be posting?") 😁 But here goes my OPINION (not substantiated by experience, Col. Duckwitz). My 2000 Dynasty with ISC-350 was originally equipped with the "wax valve" type main radiator fan control. When replacing it, the instructions clearly said (and many with EXPERIENCE have stated) that unintentionally reversing the hydraulic lines to the wax valve would result in the radiator fan running WOT all the time. Based on that, I would OPINE that a one-way (either OFF or ON) solenoid valve in one of the lines to the wax valve would cause the fan to run WOT. Perhaps someone who has actually done this will chime in.

Hmmm...we seem to be overdue for the safety lecture... 😃

I know it's common to gain some power on rear radiator coaches by replacing the fan with one which uses less of the engine's power. I'm not aware of any similar way of improving side-radiator coaches, but it's possible.

I installed the Ag Diesel Solutions device about two years ago on my 2000 Dynasty 36 with ISC-350. There was a modest increase in power but nothing dramatic. I have been running it for a couple of years now without problems. There was also an EXPECTED increase in EGT. I controlled the EGT by raising the boost. Raising boost alone absolutely does NOT increase power one iota in an engine already running properly. Should you choose to install the Ag Diesel product, I suggest you install an EGT gage FIRST. You will be surprised at how high the EGT can get in totally stock condition, so establish a baseline before you increase the fuel delivery. There are several EGT gages available now which do not require 35 foot runs of Type K thermocouple wire. They have an interface module that receives the millivolt signal from the thermocouple, amplifies it, and feeds it to the gage head along ordinary coppper wire. Also, prior to installing the Ag Solutions device, I added a FASS fuel pump, the Titanium model with two fuel filters. This mod has NOTHING to do with increasing power. It was simply insurance to hopefully extend the life of my CAPS injection pump. The CAPS injection pumps include a gear-driven pump as its "primary" section. That gear pump sucks the fuel from your fuel tank through a very long hose and supplies the fuel to the injection side of the pump. There will be (of course) a negative pressure (vacuum) at the fuel entry to the CAPS pump. Cummins says their CAPS pumps can tolerate as much as Negative 5 PSI at the entry to the CAPS pump. There are quite a few documented cases that point to failures of the ($2000-$5000) CAPS pump being due to inadequate fuel flow THROUGH the pump. In theory, the gear pump supplies considerably more fuel than required for injection, and the excess is returned to the tank through a manifold in the stock lift pump and a hose from the lift pump manifold to the fuel tank. By design, this excess fuel is used to cool the CAPS pump. When fuel filters become clogged (or any other condition restricts fuel flow) the amount of fuel available to cool the CAPS pump is reduced. When filters are so clogged that you experience power loss from the engine, the amount of cooling fuel has become zero. The FASS (or any other brand) fuel system supplies a POSITIVE pressure to the input section of the CAPS pump and insures there is always excess fuel passing through the pump, thereby cooling and lubricating it adequately. Is this NECESSARY? Obviously not. Look how many CAPS pumps have survived high mileage with no problems. But I think the evidence supports the fact that frequent, repeated fuel starvation can cause problems for the CAPS pump. The FASS (or other) pump prevents fuel starvation. Lastly, the FASS pump "bypasses" a very large quantity of fuel (approximately 95 gallons/hour) through a dedicated return line to the fuel tank after passing it through its two fuel filters, so your fuel is being constantly "polished" (filtered) any time the FASS pump is operating. Along with the installation of the FASS fuel pump, I installed a fuel pressure gage. My reason was initially that I simply wanted to see that the FASS pump system was working properly, since if it ceased functioning, the CAPS pump would have to suck even harder to draw fuel through the long line AND the internals of the FASS pump. But there has been a really useful side-benefit to the fuel pressure gage. During normal operation, even under WOT (wide open throttle), the fuel pressure is 15 PSI. If it ever drops, even to 10 PSI under WOT, there is a fuel filter that needs changing. So now I only change filters when necessary, not on a time-based schedule. Also, the FASS pump becomes a "priming pump" so that it is not necessary to pre-fill fuel filters, even though that is a habit for me that I do not care to change. Before asking questions, it will help you to read the several posts in the Cummins Engine forum on iRV2. There is a lot of good information that will help you if you are considering modifications like these. Of course there is a lot of BS there from over-enthusiastic, non-technical types, and you need to be able to separate the wheat from the chaff. Example: 1) Someone replaces their ignition switch and now the coach runs better, idles smoother, and has more power. 2) A new low-restriction exhaust system has increased power noticeably. 3) Adding the FASS pump alone has increased power of the engine noticeably. 4) A self-proclaimed "expert" warns that increasing boost can cause a DIESEL engine to burn pistons due to "lean mixtures". 5) Increased boost pressure has resulted in dramatic power increases.

I did this on my coach. I measured the voltage drop before adding the additional relays and it did not seem to me that it would make much difference...and it did not. I suggest you measure the voltage drop before making this modification. The voltate drop was less than 1 volt in my case. In cases where there is significant voltage drop it would likely help. It did nothing to help me.