FASS Fuel System Install

Topic: FASS Fuel System Install (Read 2826 times) previous topic - next topic

Re: FASS Fuel System Install

Reply #25 – May 29, 2024, 11:19:16 am

Quote from: dsd – May 29, 2024, 10:01:23 am

So I too think running the return through the ECM fuel cooler will add additional cooling for the ECM. When I asked about the fuel cooler I was asking about a fuel cooler outside of your CAC. You can look through the outer louvers and see if you have one installed. The ECMs need all the cooling they can get and running at higher power settings, hotter outside temperatures and less total fuel in the tank will see higher ECM operating temperature. You will see the fuel tank temperature rise quite high. There was a changeover when they started adding the fuel cooler and I think your build was near that time. If you dont have one, I would add one on my coach. ECM failure is not fun at all.

I dont know where the ECM is, but that blue hose in the photos above goes to the fuel cooler outboard of the CAC. I tried to get a photo of it, but it came out poorly and was worthless. The blue hose goes to a finned 3 tube aluminum cooler, and then there is a black fuel hose from the cooler that looks to be the return line back to the tank.

Re: FASS Fuel System Install

Reply #26 – May 29, 2024, 11:43:30 am

The ECM is right before beside the tee you put in for the Fass system in your first picture.

Re: FASS Fuel System Install

Reply #27 – May 29, 2024, 02:24:37 pm

Quote from: oldguy – May 29, 2024, 11:43:30 am

The ECM is right before beside the tee you put in for the Fass system in your first picture.

Copy. So with that being the case, I believe my TEE was installed downstream of the ECM, and the return flow from the FASS unit itself isn't contributing to any additional flow through the ECM.

I am not familiar with all the plumbing of this fuel system, but I suspect that the lift pump itself WILL increase return flow through the ECM unit seeing as it is a constant volume pump. Any unneeded fuel at the injection pump is presumably sent back through the ECM and fuel cooler to the tank, and this "surplus" fuel has to be a much higher volume that the previous system since it was operating under vacuum/suction, and now will have positive pressure from the lift pump.

I may be incorrect, but my assumption is the old Winn/Racor setup was not a lift pump. The little pump for air purge only operated when commanded from the little control unit. I never heard a pump or saw operation of that unit key on /engine off, unless I commanded an air purge.....

Re: FASS Fuel System Install

Reply #28 – May 29, 2024, 02:37:00 pm

Curious where does the cooling fuel for the ECM come from is it before or after the injection pump, when I plumbed mine, I capped the lift pump and ran directly the injection pump, is the ECM getting cooled this way

Re: FASS Fuel System Install

Reply #29 – May 29, 2024, 02:47:44 pm

Quote from: fatheeler – May 29, 2024, 02:37:00 pm

Curious where does the cooling fuel for the ECM come from is it before or after the injection pump, when I plumbed mine, I capped the lift pump and ran directly the injection pump, is the ECM getting cooled this way

I just want to note that you and I have different engines, so our fuel systems are likely very different. My photos only pertain to the M11 engine and my coach is a 2000 year model.

Re: FASS Fuel System Install

Reply #30 – May 29, 2024, 03:40:16 pm

One thing I need to input at this point now that different engines have come up. Scott (dsd) and myself have found out that sometime during the engine upgrades they changed the routing of the fuel flow. To expand on this our '97 M-11 and several others that I am aware of the fuel comes from the fuel tank, through the primary filter, to the ECM cooler, then to the 2ndary fuel filter, and on to the engine fuel pump. All unused fuel is returned to the tank, some coaches straight to the tank and some went through a cooler mounted in front of the CAC.

Scott has found (he can expand if I am mistaken) some coaches the return fuel to the tank goes through the ECM cooler after it passes through a cooler that is mounted in front of the CAC.

So to be sure what set up you have you will need to do some snooping around on your exact coach.

Mike

Re: FASS Fuel System Install

Reply #31 – May 29, 2024, 06:31:47 pm

Mine runs through the cooler in front of the cac then back to the tank, can't find any info on this online
Thanks
Mike

Re: FASS Fuel System Install

Reply #32 – May 30, 2024, 04:54:04 pm

Had a long talk with tech support today. He was in no hurry to rush me off the phone, it was nice to have someone knowledgeable about the product not shooing you away so they can take the next call. Made me feel even better about my purchase.

The primary reason for my call was that the installation instructions call for a 30amp fuse on the positive lead to the lift pump motor, but a 10amp is supplied. It was confirmed that 10amp is correct for this model.

Second question was about misc operations of the coach with Key on/Engine Off. He suggested pulling the fuse if I intended to have KO/EO for an extended period. Probably not a big deal, but there are a few times where I turn the ignition key to on position without starting to do something with the coach - like extend or retract the slide. Little bit of a pain to remember to go back and pull the fuse, likely not necessary for the slide procedure. He said running the pump without the engine running is not an issue as long as there are no other issues with the fuel system, the fuel will just be circulating back to tank. I think a good upgrade to this system would be a some kind of relay with a timer (unsure if anything like this exists) that gets power only when the engine is running. After 10 or 15 seconds of no engine on signal, it would kick the lift pump off.

He strongly recommended carrying spare proprietary FASS filters (which I don't have). Bad fuel can cause clogging and added draw from the motor and blow the fuse. He did say it is a fail safe draw thorough system, so the engine should still run if the lift pump loses power - the injection pump would pull fuel through the FASS system. We didn't get into the details of this. I'm crossing my fingers on the spare filters, I didn't buy any at time of purchase. I've put 30,000 or so miles on the coach and have yet to have any bad fuel issues.....FASS does have a list of recommended cross referenced filters, though they say only use them short term until the correct filters can be procured. They have a great Distributor finding application on their site, I call the 5 closest to me this morning to try to get my hands on some spare filters and no one stocked them.....

Will report back on my thoughts of this upgrade over the weekend once we arrive to the destination.

Re: FASS Fuel System Install

Reply #33 – June 02, 2024, 05:28:02 pm

I cant say for sure it was all due to the FASS because there are a couple of variables that changed, but I just drove from SoCal to Southern Idaho and i didnt touch 3rd gear once. Typically i would hit every large grade and have to shift down to 3rd to keep the rpms up and temps down. Now i can pull those same hills in 4th. I guesstimate fuel mileage to be between 7 and 8mpg pulling 9k enclosed trailer at 60-65mph average speed.

I would do the FASS again in a heartbeat.

Re: FASS Fuel System Install

Reply #34 – June 07, 2024, 06:49:06 pm

Quote from: evantwheeler – June 02, 2024, 05:28:02 pm

I cant say for sure it was all due to the FASS because there are a couple of variables that changed, but I just drove from SoCal to Southern Idaho and i didnt touch 3rd gear once. Typically i would hit every large grade and have to shift down to 3rd to keep the rpms up and temps down. Now i can pull those same hills in 4th. I guesstimate fuel mileage to be between 7 and 8mpg pulling 9k enclosed trailer at 60-65mph average speed.

I would do the FASS again in a heartbeat.

I'm glad you're pleased with your FASS. However your results are pretty much what should be expected from your motorhome size and engine. In the absence of actual side-by-side test results of any FASS installation I still believe you could have saved time and money and had equivalent results by simply replacing the old Winn system with a Parker/Racor 790R30. I remain very pleased with my installation.

Re: FASS Fuel System Install

Reply #35 – June 08, 2024, 10:59:59 am

I've had my FASS system running now for a bit over 2 years. I would highly recommend spare filters as I would for all the filters on the coach. I always get mine in the Multi pack from Amazon. Considering the price of any types of fuel filters, to buy the Fass ones in a multi pack is not that expensive.
.
Amazon.com: FASS Titanium Series Fuel Filter & Water Seprator Pack Combo Of...

I would also recommend a Fuel pressure gauge on the dash for monitoring the system. I put one in during my FASS install and on a recent trip darn glad I did.

My Fass system normally produces in the range of 15-18 psi (running/idle). About a year ago I started to notice that during running I was more down around 10 psi, so figured to replace the filters prior to a 2 week outing. I cut them open and the primary filter, which is nothing but pleated very fine stainless had quite a bit of black slimy stuff embedded in it ( well over 50% of the surface area. As this was my first set of filters, and the condition of the tank was unknown at that time, I was not surprised by the find. I also cut open the second filter which is a moisture separator, inside it looks like a K&N air filter, some sort of fiber between two looser stainless mesh layers. if it had any in it near impossible to tell. After new filters back to the 15-18 range.

Move forward to this year, about 3k miles later. We left for a long weekend, left house and about an hour out, those same pressures were reading 18 idle and about 5 psi running. I pulled over, swapped in a new set, all went back to normal 15/18.

When we got back from the trip performed a similar autopsy of the filters. Primary fuel was near spotless, secondary also spotless. There is no way in hell any particles are ever going to be seen on the second filter, and in my opinion, wet fiber is wet fiber regardless if water or diesel is making it look wet. I Only assume I Must have gotten a large amount of moisture from somewhere and the secondary did its job. Which in turn caused the pressure drop. I never blew a fuse, but at least I was still supplying positive pressure to the CAPS pump.

Keeping positive pressure to the CAPS injection pump is the main benefit of a FASS or Airdog system.. The tiny 30 second lift pump is the main reason behind most CAPS failures, and one of the most non proud moments in Cummins history. Ask any Cummins tech worth their weight in salt, they will all tell you the same.. Having the extra fuel polishing and air removal of a FASS or Airdog system, is just an added benefit.

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Re: FASS Fuel System Install

Reply #36 – June 08, 2024, 08:34:10 pm

I installed a fast pump 30,000 miles ago and in the last two trips I have noticed my pump has fallen off 2 PSI. my alarm point used to be at 12 and now it's at 10 at full load. ordered a new pump and will install it and see if the pump has deteriorated over that time. Idling pressures are both the same but full delivery pressure is 2 PSI lower.

Re: FASS Fuel System Install

Reply #37 – June 08, 2024, 08:41:42 pm

Have you changed the fuel filter?

Restriction in either of the filters could account for the PSI drop as well as a pump issue.

Re: FASS Fuel System Install

Reply #38 – June 08, 2024, 09:00:36 pm

Yes, have replaced the filter several times way more than I needed to. I'm kind of excited to see if the new pump of the same make and same model will give me the same result.

Re: FASS Fuel System Install

Reply #39 – June 08, 2024, 09:02:55 pm

I don't see any problem as positive pressure is all we're actually looking for with this caps system

Re: FASS Fuel System Install

Reply #40 – June 08, 2024, 09:05:38 pm

I wonder if they have a pressure relief valve.

Re: FASS Fuel System Install

Reply #41 – June 08, 2024, 09:20:22 pm

Maybe in the original lift pump design . I remember that fass and cummins told me they would not put more than 19.5 pounds to caps pump

Re: FASS Fuel System Install

Reply #42 – June 08, 2024, 09:21:04 pm

Suction side

Re: FASS Fuel System Install

Reply #43 – June 09, 2024, 09:14:28 am

Quote from: evantwheeler – June 02, 2024, 05:28:02 pm

I cant say for sure it was all due to the FASS because there are a couple of variables that changed, but I just drove from SoCal to Southern Idaho and i didnt touch 3rd gear once. Typically i would hit every large grade and have to shift down to 3rd to keep the rpms up and temps down. Now i can pull those same hills in 4th. I guesstimate fuel mileage to be between 7 and 8mpg pulling 9k enclosed trailer at 60-65mph average speed.

I would do the FASS again in a heartbeat.

Well finally got motivated enough to order a FASS system. Mechanically this was about the last expensive project. Although the ISM is CAPs free system I still believe its advantages mandated going that route. Ordered spare filters with initial purchase. Mike I really like the idea of viewing a pressure gauge during operation. I do know for a fact that currently my system operates under a vacuum. Fourdaysoff Jim also ordered a system and had mentioned that they were on sale and should be held accountable for me pulling the trigger on the purchase. If anyone has remote pressure indicator information a separate thread would be appreciated or I'll post what I find.

Re: FASS Fuel System Install

Reply #44 – June 09, 2024, 10:31:14 am

Quote from: opelgt327 – June 08, 2024, 09:20:22 pm

Maybe in the original lift pump design . I remember that fass and cummins told me they would not put more than 19.5 pounds to caps pump

I called 2 different Cummins shop during my purchase phase, both stated the CAPS pumps was rated at 24psi max on the incoming side.....countless FASS and Airdog pumps have been installed on CAPS systems over the past decade or so.

Re: FASS Fuel System Install

Reply #45 – June 09, 2024, 10:41:33 am

Quote from: dsd – June 09, 2024, 09:14:28 am

Well finally got motivated enough to order a FASS system. Mechanically this was about the last expensive project. Although the ISM is CAPs free system I still believe its advantages mandated going that route. Ordered spare filters with initial purchase. Mike I really like the idea of viewing a pressure gauge during operation. I do know for a fact that currently my system operates under a vacuum. Fourdaysoff Jim also ordered a system and had mentioned that they were on sale and should be held accountable for me pulling the trigger on the purchase. If anyone has remote pressure indicator information a separate thread would be appreciated or I'll post what I find.

Scott,

As for the remote pressure monitoring, I ordered this one to go with my install when I did it few years back.
Amazon.com: GlowShift Black 7 Color 30 PSI Fuel Pressure Gauge Kit -...

I would like to have had a dash matching Stewart Warner but they are way to proud of their gauges. This one has worked great. BUT, I really need to take the time to actually mount it in the dash, (there is room) but I need to remove all gauges, pull the bezel and drill as it is a tight fit.
At the moment I have it mounted to the bottom of the dash, but have to go out of my way to see it. The recent drop to 5 PSI made me realize I need to be able to more readily see it.

I used one of the spare Foretravel wires to bring the signal back to the dash from the Fass that I mounted above my starting batteries.

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Re: FASS Fuel System Install

Reply #46 – June 09, 2024, 11:48:06 am

Quote from: mkc1962 – June 09, 2024, 10:41:33 am

Scott,

As for the remote pressure monitoring, I ordered this one to go with my install when I did it few years back.
Amazon.com: GlowShift Black 7 Color 30 PSI Fuel Pressure Gauge Kit -...

I would like to have had a dash matching Stewart Warner but they are way to proud of their gauges. This one has worked great. BUT, I really need to take the time to actually mount it in the dash, (there is room) but I need to remove all gauges, pull the bezel and drill as it is a tight fit.
At the moment I have it mounted to the bottom of the dash, but have to go out of my way to see it. The recent drop to 5 PSI made me realize I need to be able to more readily see it.

I used one of the spare Foretravel wires to bring the signal back to the dash from the Fass that I mounted above my starting batteries.

DON'T drill the hole till your sure its not that 600V back lighting panels. Will kill it I too was looking at those already. Great mind think alike

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Re: FASS Fuel System Install

Reply #47 – June 09, 2024, 09:32:45 pm

Quote from: dsd – June 09, 2024, 11:48:06 am

DON'T drill the hole till your sure its not that 600V back lighting panels. Will kill it I too was looking at those already. Great mind think alike

HA....MOT already fried all of that by drilling a 1/2" hole straight through that ribbon. They installed a BlueOx steering stabilizer for the owner I bought from just a few month prior to our purchase. About 1 month into owning I kept smelling a faint burning on occasion. I finally caught the arcing one night while driving in the dark. Once home, I pulled the entire dash, The push=button for setting the steering stabilizer was the issue, or actually the high voltage lighting Ribbon that was shorting to ground. To boot, there were dozens of cheap scotch locks, loose wires, Several grounds just hanging, etc....according to PO supposedly MOT did several electrical items for them under the dash...This along with several other things PO stated MOT did, I have seen all I needed to see about the quality of work by that place. I may have bought our coach there, but if they were straight across the street I would never take my coach there for work.

Re: FASS Fuel System Install

Reply #48 – June 09, 2024, 11:20:45 pm

Quote from: mkc1962 – June 09, 2024, 09:32:45 pm

HA....MOT already fried all of that by drilling a 1/2" hole straight through that ribbon. They installed a BlueOx steering stabilizer for the owner I bought from just a few month prior to our purchase. About 1 month into owning I kept smelling a faint burning on occasion. I finally caught the arcing one night while driving in the dark. Once home, I pulled the entire dash, The push=button for setting the steering stabilizer was the issue, or actually the high voltage lighting Ribbon that was shorting to ground. To boot, there were dozens of cheap scotch locks, loose wires, Several grounds just hanging, etc....according to PO supposedly MOT did several electrical items for them under the dash...This along with several other things PO stated MOT did, I have seen all I needed to see about the quality of work by that place. I may have bought our coach there, but if they were straight across the street I would never take my coach there for work.

Whoops. That ain't right

Re: FASS Fuel System Install

Reply #49 – June 11, 2024, 09:08:42 pm

An off-topic exchange has been moved to its own topic Let's please stay on topic here - installation of the FASS system. Not opinions on the FASS system.

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