Hohn installs Wildcat Max Flow fuel system...
01-30-2004 | 09:49 PM
#1
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From: Cummins Technical Center, IN
Hohn installs Wildcat Max Flow fuel system...
The product: Wildcat Diesel max-flow fuel system
The results:
- starting problem went away. It fires first time, every time now.
- Can't pull FP below 11psi-- EVER. Idles at 17psi, cruises at 14-15, and WOT is 11-12psi. This is a GREAT product!
- Truck runs a lot better-- smoother acceleration, slightly quieter idle. Smoother on the hwy.
The install:
1. First I removed the intake horn and the intercooler pipe so I would have a little better access.
2. Open the water drain to empty the fuel filter canister. Have a receptacle handy.
3. I disconnected the banjo at the VP (17mm, but 11/16 works, too), and removed the Fitch Fuel Catalyst that I had plumbed between filter and VP.
4. Into the VP44 inlet, install the -8 adapter that is tapped with a 1/8"NPT hole in the side. Here's a tip: if you can't get the tapped hole to line up into a useable position when the adapter is tightened, you can take a washer off the old banjo fitting and it will act as a spacer-- BINGO! perfect alignment and no leak.
I then installed my aluminum AN adapter into the max-flow fitting and connected it to the -6AN line that runs to my FP gauge.
5. Now you need to make the braided line that will run from the VP to the filter. I was lucky enough that the line right out of the box had on end i could use, so i didn't have to cut it to put the end on. Otherwise, tightly wrap with electrical tape (strapping tape works, too-- I used it) the area near the end where you are going to make your cut.
Cut the outer braid ONLY with a dremel cutoff wheel (right through the tape). Take a lot of time to do this, because the teflon (plastic) inner line will melt if you aren't careful. Melting the inner part will make putting the end on almost impossible and you'll have to recut. I went slowly and had no problems.
Once you have the outer braid cut, cut the inner plastic hose using something very sharp- razor, box cutter, etc. I was able to use my Klein loppers and it made a nice clean cut.
Now slip the collar part of the fitting over the freshly cut end BEFORE you remove the tape. THEN remove the tape.
The brass ferrulle goes outside the clear inner hose, but UNDER the braid. As you slide the ferrule on, notice that there are grooves cut inside it. Be careful not to slide the ferrule down too far, or you won't be able to get the end on. Look to see where the end of the clear part is inside the ferrule. If the end is past the groove closest to you, it's on too far. Take a pliers and pull the ferrule off a little bit. You want the end to be in between the two grooves insde the brass ferrule.
With the ferrule in position, you can now insert the fitting end into the hose. You should use the STRAIGHT fitting, since we are making the connection to the VP44.
With the fitting end firmly seated, bring up the collar and screw the fitting together. Use two wrenches to tighten it. The two parts should almost butt up against each other, so make it good and tight (but don't play He-Man or you can strip the fitting).
You are DONE putting the end on the hose!
6. Connect the hose end to the fitting at the VP. Now you can see how much hose you will need to run between the VP and the filter bottom. Make sure to leave enough room for a nice smooth arc in the line-- the line has to approach the VP at a gentle angle, like an airplane flying in an approach pattern.
Mark the point where you will make your cut.
7. Disconnect the fitting at the Vp so you can cut the other end to length.
8. Cut the line and install the ends as described above. You will use a 90 degree hose end for all but the last connection (rubber line to tank, working towards the back of the truck). You should now have an assembled line of proper length for the filter-to-VP connection, and some leftover braided hose.
9. Now is a good time to dismount the Fuel filter housing. It's just TWO 10mm bolts.
10. Remove the four banjos-- two on the filter, two on the lift pump. There's no need to remove the lift pump, you can do all this from the top side of the engine. When removing the LIFT PUMP INLET banjo, do NOT let the loose end hang low-- you will create a siphon and end up with a diesel shower and/or empty tank. OR you can just clamp off the rubber line from the tank (there are some places where you can clamp it off, even though most of it has hard plastic underneath.)
11. Install the Max Flow -8 adapters where the banjos were.
12. Connect the bottom of the filter housing to the VP with the hose you made.
13. Measure how much hose you need to the short length from the lift pump to the filter. Remember, you want a soft loop in the line. If you cut it to exact length, you have no room for error (if you goof up an end), and it will be VERy difficult to make the attach the braided hose, since you will have to fight the stiffness of the braided. I routed my hose behind (or, to the driver's side of) the three metal lines that run there (they look like brake lines). This gave me a nice angle to my hose ends.
14. Assemble the hose you will use to connect the lift pump and the filter just like you did the first hose.
15. Connect the filter and lift pump using the hose you just made. This is where you will be glad to have dismounted the filter housing. It's worth mentioning that it's hard to get a 7/8" wrench to move around back there. I solved this by cutting an old wrench down so it was shorter than a regular stubby. It saves so much headache that I would recommend buying a cheapie just for this purpose. The end result you want here is a 7/8" open end wrench that's only about 5" long. You don't need much leverage for the fittings.
16. With the LP connected to the filter, and the filter to the VP, you are ALMOST ready to remount the filter.
17. Before you remount the filter, you need to connect the rubber hose to the LP inlet. This is where you will use the supplied rubber hose and the brass barb hose end from the wildcat kit. Slide the barb fitting into the rubber hose end as far as you can make it go. It will settle into the collar on the hose end.
Now, connect this brass hose end to the -8 Max-flow adapter you installed in the lift pump inlet. Feed the rest of the rubber hose back down the transmission tunnel on the driver's side.
18. Now, make sure all your fittings are tight and remount the filter housing.
19. If you have an inclined driveway, you are in luck. Position the truck so the front is higher than the back. This is to prevent a diesel shower as you disconnect the line from the tank. Also, make sure your fuel fill cap is loosened.
20. Now you need to crawl under the truck. Find the end of the hose that you connected in step 17.
21. You might want to save the hoseclamps from the stock fuel line plumbing up near the VP. You will need one for your new line from the tank
22. Slide a hose clamp over the end of your new line (from step 20)
23. Remove the stock fuel line (to the lift pump) from the clip on the frame. It's the one closer to the frame.
24. Cut the OEM line about 2 inches from where the hardline and rubber line meet. Guess what? NO DIESEL SHOWER! Slide the new hose over the hardline and tighten the clamp.
25. Double check all your connections for tightness and reassemble all the stuff you took off for access (intake horn, etc..).
26. Prime it, start it, check for leaks. Mine took a LOT of cranking to get all the air out. Don't burn out your starter!
Miscellaneous:
- Don't use thread sealant. These fittings don't need it, and it's just one more thing the VP can ingest.
The hard starting problem I had before is likely due to my shadetree install of the Fitch Fuel Catalyst. I relocated the canister so it's just before the lift pump, instead of just before the VP. I think i had a bad connection that was letting air into the fuel system, so it would lose prime every time i shut it off. This isn't a surprise since I had adpaters to adapters and the plumbing was really sloppy.
Now it starts and runs like a dream and I couldn't be happier!
Feel free to ask anything I didn't cover. i tried to mention it all (sorry it's such a long post).
This is a GREAT BOMB.
Justin
The results:
- starting problem went away. It fires first time, every time now.
- Can't pull FP below 11psi-- EVER. Idles at 17psi, cruises at 14-15, and WOT is 11-12psi. This is a GREAT product!
- Truck runs a lot better-- smoother acceleration, slightly quieter idle. Smoother on the hwy.
The install:
1. First I removed the intake horn and the intercooler pipe so I would have a little better access.
2. Open the water drain to empty the fuel filter canister. Have a receptacle handy.
3. I disconnected the banjo at the VP (17mm, but 11/16 works, too), and removed the Fitch Fuel Catalyst that I had plumbed between filter and VP.
4. Into the VP44 inlet, install the -8 adapter that is tapped with a 1/8"NPT hole in the side. Here's a tip: if you can't get the tapped hole to line up into a useable position when the adapter is tightened, you can take a washer off the old banjo fitting and it will act as a spacer-- BINGO! perfect alignment and no leak.
I then installed my aluminum AN adapter into the max-flow fitting and connected it to the -6AN line that runs to my FP gauge.
5. Now you need to make the braided line that will run from the VP to the filter. I was lucky enough that the line right out of the box had on end i could use, so i didn't have to cut it to put the end on. Otherwise, tightly wrap with electrical tape (strapping tape works, too-- I used it) the area near the end where you are going to make your cut.
Cut the outer braid ONLY with a dremel cutoff wheel (right through the tape). Take a lot of time to do this, because the teflon (plastic) inner line will melt if you aren't careful. Melting the inner part will make putting the end on almost impossible and you'll have to recut. I went slowly and had no problems.
Once you have the outer braid cut, cut the inner plastic hose using something very sharp- razor, box cutter, etc. I was able to use my Klein loppers and it made a nice clean cut.
Now slip the collar part of the fitting over the freshly cut end BEFORE you remove the tape. THEN remove the tape.
The brass ferrulle goes outside the clear inner hose, but UNDER the braid. As you slide the ferrule on, notice that there are grooves cut inside it. Be careful not to slide the ferrule down too far, or you won't be able to get the end on. Look to see where the end of the clear part is inside the ferrule. If the end is past the groove closest to you, it's on too far. Take a pliers and pull the ferrule off a little bit. You want the end to be in between the two grooves insde the brass ferrule.
With the ferrule in position, you can now insert the fitting end into the hose. You should use the STRAIGHT fitting, since we are making the connection to the VP44.
With the fitting end firmly seated, bring up the collar and screw the fitting together. Use two wrenches to tighten it. The two parts should almost butt up against each other, so make it good and tight (but don't play He-Man or you can strip the fitting).
You are DONE putting the end on the hose!
6. Connect the hose end to the fitting at the VP. Now you can see how much hose you will need to run between the VP and the filter bottom. Make sure to leave enough room for a nice smooth arc in the line-- the line has to approach the VP at a gentle angle, like an airplane flying in an approach pattern.
Mark the point where you will make your cut.
7. Disconnect the fitting at the Vp so you can cut the other end to length.
8. Cut the line and install the ends as described above. You will use a 90 degree hose end for all but the last connection (rubber line to tank, working towards the back of the truck). You should now have an assembled line of proper length for the filter-to-VP connection, and some leftover braided hose.
9. Now is a good time to dismount the Fuel filter housing. It's just TWO 10mm bolts.
10. Remove the four banjos-- two on the filter, two on the lift pump. There's no need to remove the lift pump, you can do all this from the top side of the engine. When removing the LIFT PUMP INLET banjo, do NOT let the loose end hang low-- you will create a siphon and end up with a diesel shower and/or empty tank. OR you can just clamp off the rubber line from the tank (there are some places where you can clamp it off, even though most of it has hard plastic underneath.)
11. Install the Max Flow -8 adapters where the banjos were.
12. Connect the bottom of the filter housing to the VP with the hose you made.
13. Measure how much hose you need to the short length from the lift pump to the filter. Remember, you want a soft loop in the line. If you cut it to exact length, you have no room for error (if you goof up an end), and it will be VERy difficult to make the attach the braided hose, since you will have to fight the stiffness of the braided. I routed my hose behind (or, to the driver's side of) the three metal lines that run there (they look like brake lines). This gave me a nice angle to my hose ends.
14. Assemble the hose you will use to connect the lift pump and the filter just like you did the first hose.
15. Connect the filter and lift pump using the hose you just made. This is where you will be glad to have dismounted the filter housing. It's worth mentioning that it's hard to get a 7/8" wrench to move around back there. I solved this by cutting an old wrench down so it was shorter than a regular stubby. It saves so much headache that I would recommend buying a cheapie just for this purpose. The end result you want here is a 7/8" open end wrench that's only about 5" long. You don't need much leverage for the fittings.
16. With the LP connected to the filter, and the filter to the VP, you are ALMOST ready to remount the filter.
17. Before you remount the filter, you need to connect the rubber hose to the LP inlet. This is where you will use the supplied rubber hose and the brass barb hose end from the wildcat kit. Slide the barb fitting into the rubber hose end as far as you can make it go. It will settle into the collar on the hose end.
Now, connect this brass hose end to the -8 Max-flow adapter you installed in the lift pump inlet. Feed the rest of the rubber hose back down the transmission tunnel on the driver's side.
18. Now, make sure all your fittings are tight and remount the filter housing.
19. If you have an inclined driveway, you are in luck. Position the truck so the front is higher than the back. This is to prevent a diesel shower as you disconnect the line from the tank. Also, make sure your fuel fill cap is loosened.
20. Now you need to crawl under the truck. Find the end of the hose that you connected in step 17.
21. You might want to save the hoseclamps from the stock fuel line plumbing up near the VP. You will need one for your new line from the tank
22. Slide a hose clamp over the end of your new line (from step 20)
23. Remove the stock fuel line (to the lift pump) from the clip on the frame. It's the one closer to the frame.
24. Cut the OEM line about 2 inches from where the hardline and rubber line meet. Guess what? NO DIESEL SHOWER! Slide the new hose over the hardline and tighten the clamp.
25. Double check all your connections for tightness and reassemble all the stuff you took off for access (intake horn, etc..).
26. Prime it, start it, check for leaks. Mine took a LOT of cranking to get all the air out. Don't burn out your starter!
Miscellaneous:
- Don't use thread sealant. These fittings don't need it, and it's just one more thing the VP can ingest.
The hard starting problem I had before is likely due to my shadetree install of the Fitch Fuel Catalyst. I relocated the canister so it's just before the lift pump, instead of just before the VP. I think i had a bad connection that was letting air into the fuel system, so it would lose prime every time i shut it off. This isn't a surprise since I had adpaters to adapters and the plumbing was really sloppy.
Now it starts and runs like a dream and I couldn't be happier!
Feel free to ask anything I didn't cover. i tried to mention it all (sorry it's such a long post).
This is a GREAT BOMB.
Justin
01-31-2004 | 12:26 PM
#4
Top's Younger Twin
Joined: Nov 2001
Posts: 3,743
Likes: 21
From: Thanks Don M!
The ScottyAirSystems SUCK COOOoooOoooL AIR and that Max Flow System SUCKS COoOoooL FUEL 
Safe fuel pressures with a stock lift pump even with added power and better starting etc etc.
EDIT: Make sure you check the fuel system for leaks after a few miles and again after about 50. I had this very tiny leak at the fuel pressure tapped custom metric fitting on the first inspection.
More COOL SYSTEMS coming for the 3rd gens SOON!
Thanks again to all who believe in our products!
Using them removes all doubt.
Safe fuel pressures with a stock lift pump even with added power and better starting etc etc. EDIT: Make sure you check the fuel system for leaks after a few miles and again after about 50. I had this very tiny leak at the fuel pressure tapped custom metric fitting on the first inspection.
More COOL SYSTEMS coming for the 3rd gens SOON!
Thanks again to all who believe in our products!
Using them removes all doubt.
01-31-2004 | 10:38 PM
#5
Registered User
Joined: Oct 2003
Posts: 944
Likes: 0
From: Myrtle Creek Oregon
Nooooo! Scotty & Rod thank you for a couple of good products that live up to there claims. Just love my max flow kit & scotty II air & issapro fuel pressure gauge. Great fuel pressure, & my egt's are down 150* while towing. 
02-01-2004 | 02:21 PM
#6
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Joined: Sep 2003
Posts: 1,300
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From: stupid ohio
24. Cut the OEM line about 2 inches from where the hardline and rubber line meet. Guess what? NO DIESEL SHOWER! Slide the new hose over the hardline and tighten the clamp.
brandon.
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02-02-2004 | 11:24 AM
#9
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Registered User
Joined: Apr 2003
Posts: 6,564
Likes: 6
From: Cummins Technical Center, IN
UPDATE!
Well, it turns out that all is not as well is I had posted earlier.
I dynoed on Saturday, and a friend noticed that I had a fuel like at the VP44. Sure enough. It was sufficient to allow air to be sucked in and I was losing prime.
The hard starting came back.
I spent yesterday trying different configurations of washers, redoing the hose end at the VP and a bunch of other stuff.
I finally got the leak stopped. I had to redo the "spacer" setup I made from the old banjo bolt washer (this was to get the gauge tap to line up). At first, that just slowed the leak, but didn't stop it. Turns out the leak was not at the adapter into the VP, but at the hose end connecting to this adapter. The leak was stopped by just tightening the hose end more. Those fittings are steel, so they can take a good amount of tightening.
But I still have a hard starting issue if it's been sitting for any length of time.
I will do a little more investigation, but I am kinda stumped. My fuel pressure is behaving nicely. At shutdown, FP comes down slowly instead of just dying right away. That tells me that my connections should be good, right?
I thought my VP bypass was stuck open (known to cause hard starting). But if it was stuck open, wouldn't the fuel pressure just DIVE at shutdown??? That's what has me ruling out a stuck bypass.
This morning, I cycled the grid heaters twice and it fired up instantly (surprised me). This was a cold start unplugged.
When I went to start it 90 minutes later, I had to crank it a while. The routine is the same: I crank it over a little bit, then let the LP kick in until FP is in the upper teens. Then I crank it for a while with the fuel pedal floored and it starts.
Oddly enough, I have almost 18psi at idle, but when I go to start it, it barely shows and FP at all. Then once it starts, the needle races up.
Why don't I have FP (like 2psi) at startup? I used to always get about 5psi at startup, and it fired instantly.
Sorry to hijack my own thread. This hard starting is killing me.
Justin
Well, it turns out that all is not as well is I had posted earlier.
I dynoed on Saturday, and a friend noticed that I had a fuel like at the VP44. Sure enough. It was sufficient to allow air to be sucked in and I was losing prime.
The hard starting came back.
I spent yesterday trying different configurations of washers, redoing the hose end at the VP and a bunch of other stuff.
I finally got the leak stopped. I had to redo the "spacer" setup I made from the old banjo bolt washer (this was to get the gauge tap to line up). At first, that just slowed the leak, but didn't stop it. Turns out the leak was not at the adapter into the VP, but at the hose end connecting to this adapter. The leak was stopped by just tightening the hose end more. Those fittings are steel, so they can take a good amount of tightening.
But I still have a hard starting issue if it's been sitting for any length of time.
I will do a little more investigation, but I am kinda stumped. My fuel pressure is behaving nicely. At shutdown, FP comes down slowly instead of just dying right away. That tells me that my connections should be good, right?
I thought my VP bypass was stuck open (known to cause hard starting). But if it was stuck open, wouldn't the fuel pressure just DIVE at shutdown??? That's what has me ruling out a stuck bypass.
This morning, I cycled the grid heaters twice and it fired up instantly (surprised me). This was a cold start unplugged.
When I went to start it 90 minutes later, I had to crank it a while. The routine is the same: I crank it over a little bit, then let the LP kick in until FP is in the upper teens. Then I crank it for a while with the fuel pedal floored and it starts.
Oddly enough, I have almost 18psi at idle, but when I go to start it, it barely shows and FP at all. Then once it starts, the needle races up.
Why don't I have FP (like 2psi) at startup? I used to always get about 5psi at startup, and it fired instantly.
Sorry to hijack my own thread. This hard starting is killing me.
Justin
02-02-2004 | 03:31 PM
#10
Thread Starter
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Joined: Apr 2003
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From: Cummins Technical Center, IN
OK, now when the engine is warm, I get 5 psi pre-startup fuel pressure, just like it's supposed to be.
Still hard to start. Somehow, it's losing prime.
Justin
Still hard to start. Somehow, it's losing prime.
Justin
02-02-2004 | 04:04 PM
#11
Top's Younger Twin
Joined: Nov 2001
Posts: 3,743
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From: Thanks Don M!
Did I read somewhere on one of your posts that you had hard starts prior to the Max Fuel System? I'd be curious as to what is causing that. Definately sounds like a slow leak down of some sort.
02-02-2004 | 04:06 PM
#12
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From: Cummins Technical Center, IN
Yeah, I sure did.
Here's my previous post:https://www.dieseltruckresource.com/...threadid=37235
Justin
Here's my previous post:https://www.dieseltruckresource.com/...threadid=37235
Justin
02-02-2004 | 04:19 PM
#14
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From: Cummins Technical Center, IN
Installing the Fitch made no difference in starting performance for over 15K miles. All of the starting woes began with that one really rough startup after the truck sat for 10 days.
jlh
jlh
02-02-2004 | 06:36 PM
#15
Top's Younger Twin
Joined: Nov 2001
Posts: 3,743
Likes: 21
From: Thanks Don M!
Maybe a leaky injector? Its happened to others. Me.
I had a set of DD 3s installed at DD that Lawrence had to change out and the problem was gone on the 2nd set. Not sure which one caused the starting problem. I then saw this on a truck with stock injectors. Put the DD 2s in and no hard start.
I had a set of DD 3s installed at DD that Lawrence had to change out and the problem was gone on the 2nd set. Not sure which one caused the starting problem. I then saw this on a truck with stock injectors. Put the DD 2s in and no hard start.