Air Dog Installation

[Arkansas RV]

I have a 2000 model DSDP 35’ with the 8.3 330HP Cummins ISC CAPS engine. I have been researching the last year on how best to protect my Caps 8.3 Cummins from transfer pump leaks/malfunctions, restricted filtration, which can lead to premature failure of the main gear drive pump. Much has been written on using the FASS system to rectify these problems; this article is offering another approach which I feel is better suited to “Semi” type diesels rather than diesel pickup applications, although they will work.
The Air Dog pump that I am using is the AirDog 4G FPll-150 Universal. It’s universal as they don’t offer a specific pump for motor homes. This is a demand flow pump that delivers 150-170GPH at 18-23 PSI.
I mounted the pump where my PRIMARY filter was located. A second bracket was added below the original upper bracket, these are made of 2”x1/4” and 3”x1/4 steel plate. The Universal kit comes with all necessary fittings, hoses etc. The pump brackets from AD are all 1/4” x 4” steel plate. The picture with the cross setup is what the pump mounts to; it has 3/8 rubber spacers between the cross mount and steel horizontal supports. This pump DOES NOT REQUIRE a separate line back to the fuel tank. The demand feature only pumps the quantity of fuel the engine requires at any given RPM, extra fuel is recirculated via the pump thru the two filters, thereby allowing me to tee into the Capps return line at the transfer pump manifold to return air and vapor with a small quantity of fuel back to the tank. Both sides of transfer pump manifold are capped where fuel enters and leaves to secondary filter on the side of the engine. The only purpose now for the lift pump manifold is to return fuel from engine and AD pump back to tank. My transfer pump ( lift pump) was fine but wanted to avert future problems with leaks or malfunction. All fittings where 8AN, except between transfer pump manifold and secondary filter where they were 10AN fittings. So, inlet on AD is 8AN and outlet is 10 AN going directly to secondary filter. The AD has a built in sensor to monitor the filters for occlusions/ flow. It comes with a 5psi sensor but I felt 10 psi would be more practical as I didn’t want to wait till the filters were almost occluded before changing. As fuel pressure drops due to filter occlusion it will light a LED on dash as when a 10 psi drop has been reached. AD offers both a 5 & 10 psi sensor.
Since I’m anal about things I also installed a fuel pressure sending unit on top of the #2 filter mounted to engine and have it wired and installed at the dash near where the AD LED light is mounted. Hopefully the ten pictures will transfer to show details.
After 100 miles of driving, I’ve noticed the following: 1) increased power, much better at going up hills 2) smoother engine idle 3) improved throttle response 4) quieter engine and 5) somewhat better fuel mileage, will need to go on a longer trip to verify that. There are three pics that include a lot of data that I didn’t include in the article. At idle 23 psi, driving 30-70mph 20-21psi, climbing a long 6 degree hill 19psi. Thanks for looking!

[Arkansas RV]

These are the pictures for AirDog installation.
Also forgot to mention the use of a relay when disconnecting the transfer pump wires to fool computer.

[Arkansas RV]

Attachment: picture of total kit

[imnprsd]

Arkansas RV: So you started with a Cummins/Newmar 2-filter setup...

...and your OEM fuel flow looked like this:

Tank ===> Primary Filter ==> LPM (fuel supply side) ==> Secondary Filter ==> CAPS Pump.

...with the primary (20u filter) was mounted in a side cargo bay; and the secondary filter (10-micron with WIF) was mounted against the engine?

Then you installed the AirDog in the filter bay (in place of the primary filter) and now your fuel flow looks like this:

Tank ===> Air Dog ==> #3 Filter ==> CAPS Pump.

* And you cap-off both sides of the LPM fuel supply side... so no fuel will ever enter or leave the old Cummins lift pump.

So now that I understand all this, I have some questions:

1) What did you have to do in order to remove the old filter mounts and install those "flat" steel plates? Were those plates part of the AirDog kit?

2) Why did you decide to keep the #3 filter when you have 2 filters in the AirDog?

3) What trick did you use to find and pull down the ECM to Lift Pump wires? I understand it's often difficult to reach these.

4) Can you share a few pictures of your dash fuel pressure gauge and LED light?

5) How much did it cost for parts? How much installation time is involved?

Your efforts are much appreciated!

[Arkansas RV]

Imnprsd, I mixed up the filters some what. The original AirDog water separator is a 140 micron filter on the intake side with no plastic bowl to view the fuel. I replaced this filter with a Wix 33242 water separator with a 10 micron rating And it has the plastic bowl so you can view the fuel. The Second AirDog filter is a FF-200-MG that contains a filtering media that has a 6 micron rating. The fuel then is pumped to the original #2 filter that’s mounted on the side of the engine, which has now become filter #3 with a 2 micron rating
1) the original primary filter was mounted to a 2” x 1/4” plate welded to the chassis. The picture with the 4” x 1/4” steel plate in the shape of a cross is part of the AirDog kit. I added a 3” x 1/4” steel plate and welded it to the chassis lower down so there was an attachment point on top as well as the bottom. You can’t tell from the photo, but there is a 3/8” rubber bushing top and bottom isolating the AirDog mount from the chassis mount.
2) the third filters is a 2 micron Wix # 33422. I kept it in place as Recommended by AD because newer semi engines could have warranties voided without it. This didn’t apply to me but I deduced three is better than two and it was already there.
3) It was very difficult to get to the transfer pump wiring especially on this Spartan chassis We thought we would have to drop the starter but with four hands we got it done. We lengthened the wires to the computer to add a relay so computer would think the transfer pump was still there and won’t set codes.
4) fuel pressure gauge is a Glow Shift gauge made by MaxTow # MT-DV11_30. It measures fuel pressure from 0-30 psi digital and analog; no pics yet as I have not mounted them of this writing
5) the AD industrial pump was around $900 plus tax. It took us about two days to do the install. Most of the time was running conduit for Gauge wiring from sending unit, trigger wire for the pump relay and two wires for pump sensor.
Special thanks to Airdogdiesel.com ph # 877-463-4373 or 573-606-6078* lance Hess head tech for AirDog

[RockyCliff]

Arkansas RV
Thanks for the excellent info on the AirDog installation. I have a 2001 HR ISC on a Roadmaster RR8 chassis. I will be doing a positive pressure upgrade for all the reason you and others on this forum have advised and experienced. Like you I have not yet experienced the lift pump gasket issue or other signs of CAPS pump cavatation, but know I am on borrowed time.

My OEM fuel delivery set up is as yours and my plan was to do the upgrade exactly as you have described. I have not yet decided which system to go with, FASS or Airdog. Until now no one to my knowledge on the forum had shared experience with Airdog
I have a couple questions.
1. There is enough experience with FASS setups the we know the 15 psi positive pressure constantly to the CAPS pump is not an issue. However, while we know the FASS return flow requires a dedicated return to the tank and the AirDog return is minimal, do we know that adding the AirDog return teed into the CAPS return is not a problem? I don't have data or specs but historically Cummins has had issues with too much restriction on fuel return line.
2. I see you ran a new line from the AirDog to the engine mounted secondary filter but did you use your existing line from the fuel tank to the AirDog? Given the age of our coaches I am trying to figure out how to run a new supply line from the tank. From your photos your lines look to be of the same material as mine. It has been mentioned on the forum that pre 2003 fuel lines are probably being damaged by the ULSD.

Thanks again for all you have shared.
Cliff

[Arkansas RV]

Originally Posted by RockyCliff

Arkansas RV
Thanks for the excellent info on the AirDog installation. I have a 2001 HR ISC on a Roadmaster RR8 chassis. I will be doing a positive pressure upgrade for all the reason you and others on this forum have advised and experienced. Like you I have not yet experienced the lift pump gasket issue or other signs of CAPS pump cavatation, but know I am on borrowed time.

My OEM fuel delivery set up is as yours and my plan was to do the upgrade exactly as you have described. I have not yet decided which system to go with, FASS or Airdog. Until now no one to my knowledge on the forum had shared experience with Airdog
I have a couple questions.
1. There is enough experience with FASS setups the we know the 15 psi positive pressure constantly to the CAPS pump is not an issue. However, while we know the FASS return flow requires a dedicated return to the tank and the AirDog return is minimal, do we know that adding the AirDog return teed into the CAPS return is not a problem? I don't have data or specs but historically Cummins has had issues with too much restriction on fuel return line.
2. I see you ran a new line from the AirDog to the engine mounted secondary filter but did you use your existing line from the fuel tank to the AirDog? Given the age of our coaches I am trying to figure out how to run a new supply line from the tank. From your photos your lines look to be of the same material as mine. It has been mentioned on the forum that pre 2003 fuel lines are probably being damaged by the ULSD.

Thanks again for all you have shared.
Cliff

Cliff, the Air Dog line that tees into the Caps return line at the transfer manifold carries very little fuel and pressure, mostly extracted air, water vapor and very little fuel. Another thing I’ve read is deteriorating fuel lines on older coaches. My fuel lines were perfect and no signs of breakdown. In fact an experienced diesel shop owner/ mechanic helped me and he said he’s never seen any either and he deals with trucks 25-30 years old.
Second, The only reason I changed the line to the secondary filter was because it was 10 AN coming out of transfer pump to secondary filter, so I opted to run 10AN line from pump to secondary filter; AirDog sends both 8AN and 10AN fittings with their kits.
You might have noticed I run higher fuel pressures Than others that have done this upgrade. The AD is an industrial pump for larger diesels as noted in write up and it’s pressure is adjustable. I talked with an injection pump builder here in Arkansas who knows the Capps engines inside out And been in business 25 years plus and he said these engines can easily stand fuel pressures in the mid 20s. They test their rebuilt units at 35psi. He also mentioned to get rid of the transfer pump as it’s the weak link in the fuel system.

[imnprsd]

I would just like to echo what "Arkansas RV" and his "seasoned mechanics" said about old and rotted-out fuel lines.

I read about some owners who elected to replace their fuel lines, but to my knowledge these owners did NOT upgrade to a FASS or Airdog electric fuel pump. That said, I can only conclude the following:

* If there is any truth and value to replacing older pre-2003 fuel lines, due to a different rubber composition, it would have to do with these fuel lines being able to "suck-in" air... which would then render the CAPS Low Pressure Gear Pump with less than the -5PSI needed to pump enough fuel to the CAPS High Pressure Gear Pump.

Air = Bad
FASS or AirDog = GOOD!

* Now if you take that same fuel line and run an AirDog or FASS electric fuel pump, which filters out any air that may get induced by an old fuel line or leaking gasket, this point is now mute, because both of these pumps are designed to remove air in the fuel and return that air to the tank.

My guess is that these owners who replaced their old fuel lines did so on the advice of their mechanic who no doubt charged them big bucks to repair.

The owner then leaves the shop thinking they got his/her monies worth, because the engine is now running right. However, I would argue the better solution (for less money) would be to upgrade to either the FASS or AirDog electric fuel pump.

So, IMO, if there is any truth to air getting sucked into older fuel lines, to the best of my knowledge, not one of these owners reported fuel leaking out of those same, old fuel lines.

That said, I would pay no attention to old fuel lines if you upgrade to a FASS or AirDog.

I would add, that the money you spend to upgrade to a FASS or AirDog is protect your CAPS injection pump and ECM from premature failure; which if you have been following my other posts, this repair cost me $9,500 at a Cummins dealer in 2017; and my mileage at the time was ~73,000 miles.

And just so you know, when your CAPS injection pump blows... 9x out of 10 you also blow your ECM because the suppression diode designed to protect the ECM from "transient spikes" is not enough to protect the ECM when the CAPS Stator goes "haywire!"

What irks me through my whole repair process is this: Not once did any Cummins or Freightliner mechanic tell me about upgrading to FASS. And it was another 10,000 miles later I began to experience fuel delivery problems. (Short story: IT WAS NOT DUE TO BAD FUEL OR CLOGGED FUEL FILTERS.)

What a shame! ...And that my friends is why IRV2.com is so awesome! ...Because now you know what you need to do in order to avoid a premature CAPS & ECM failure.

To say it another way: With a FASS or AirDog upgrade pump, there is no reason your CAPS and ECM will NOT last the life of your engine!

The reason for this is that both FASS or AirDog filter out the air in the fuel lines and provide positive fuel pressure to your CAPS injection pump -- keeping it lubricated and cool -- especially under load!!!

The major difference between FASS-TS & Airdog-II-4G pumps has to do with the way they are designed, but from an installation point of view your decision to choose one over the other might have more to do with your willingness to run a dedicated FASS fuel return line to the tank, which the AirDog-4G does not need, according to "Arkansas RV." ...And I believe him. He is reporting great results.

On the other hand, FASS may do a better job filtering fuel over-and-over, because it is constantly pumping 95GPH and returning unused fuel to you tank.

FASS calls this "Fuel Polishing," but how do I really know if this is a benefit not? ...I guess I have to believe more fuel being filtered, more often, is better, but is it really?

The AirDog-4G is a demand flow pump and will not return very much fuel to the tank. ...But after 10,000 miles who cares! ...Because I would think by then you have a very clean tank, but maybe not? ...These bio-fuels contain a lot of "crap" for lack of knowing what I should call it.

My fuel tanks were in bad shape and I believe I had an algae problem. So maybe in these cases the FASS pump will be a better choice? You decide. I'm happy with my FASS-TS pump, and it really was not a big-whoop to install a fuel return line to the filler-neck of my tank. (See my thread on this subject.)

https://www.irv2.com/forums/f123/cum...mp-458337.html

On the other hand, "Arkansas RV" went with the AirDog-II-4G pump and he "T'd" into the CAPS fuel return line without any difficulty. So it's a coin toss at this point as to which pump might be better than the other. IMO.

[RockyCliff]

Arkansas RV,
Thanks for the quick reply and additional info. It's reassuring info on the fuel lines as I believe I would have to drop my tank to run new ones. I'll keep the forum posted on my decision and progress.
Cliff

[Meames1]

ArkansasRv ,
Thanks for posting this. I was on the fence between AD and FASS and this post confirmed what I have been thinking. My major concern was that on my coach running a new return line would be a huge project the way the basement was made. I liked the idea of not having to run a new line.
Your post turned me onto the industrial side of AD pumps. I ended up purchasing their setup for a Cummins N14 with remote filter after reviewing all their kits and the plumbing components. I actually "could have" installed the kit without buying any additional line or fittings. However, I decided to remove the #2 factory filter from the side of my engine and remote mount it next to the AD to make filter changes easier and not having diesel run down the starter while changing. That required a few feet of -10 braided hose and two fittings.
My setup is an ISC with all -10 lines to the #1 filter, to the stock lift pump, then to filter #2, and finally to CAPS pump. My return line on the stock lift pump manifold is -8, which is the size tee that the N14 kit came with and to the -6 adapter required for the AD return.
I will cap off the stock lift pump (I did have to buy the two caps), and install a relay to fool the computer.

Thanks again on the info.

[kenwyatt]

Great post . Have read a little about them but I have a 525 hp Cat and not sure if I may have the same issues but suspect and common rail system would. If you don’t mind sharing what did the upgrade cost you as it sounds like you were the labor. Give yourself $150 an hour and go get a FEW good steak dinners.

[Arkansas RV]

Originally Posted by Meames1

ArkansasRv ,
Thanks for posting this. I was on the fence between AD and FASS and this post confirmed what I have been thinking. My major concern was that on my coach running a new return line would be a huge project the way the basement was made. I liked the idea of not having to run a new line.
Your post turned me onto the industrial side of AD pumps. I ended up purchasing their setup for a Cummins N14 with remote filter after reviewing all their kits and the plumbing components. I actually "could have" installed the kit without buying any additional line or fittings. However, I decided to remove the #2 factory filter from the side of my engine and remote mount it next to the AD to make filter changes easier and not having diesel run down the starter while changing. That required a few feet of -10 braided hose and two fittings.
My setup is an ISC with all -10 lines to the #1 filter, to the stock lift pump, then to filter #2, and finally to CAPS pump. My return line on the stock lift pump manifold is -8, which is the size tee that the N14 kit came with and to the -6 adapter required for the AD return.
I will cap off the stock lift pump (I did have to buy the two caps), and install a relay to fool the computer.

Thanks again on the info.

Attachment 284639

Attachment 284640

Meames, you will be very happy with the setup. My 8.3 ISC 330 hp has come alive, not that it was a slouch. I thought about the remote filter for the block filter but chose not to. With this set up you won’t need to change the filters as often with the electronic monitoring system which was a plus for me.
Spoke with AirDog today and they will soon be a supporting vender on IRV2. The 150/200 series pumps support up to 650HP too

[Arkansas RV]

Kenwyatt, AirDog makes a specific Kit/pump for the Cat engines. Call one of the two ph numbers in my earlier post and talk with Lance, he is very knowledgeable On all the systems up to 650 HP. These pumps come with a 4 year warranty too.

[kenwyatt]

Thanks I will check into it