Manual CTIS control how to.

[adamsoffroadperformance]

I don't have a pic of the one I built because it's in a truck that's not here so credit to the pics owner. (edit) I found the owner of the pic is tjhuffy and he also did this setup to his LMTV earlier this year.


This is how to bypass the ctis controller to make it a manual system if you are having controller issues. The system needs 20psi minimum to open the wheel valves so it can air up or air down the tires. With the manual regulator you set it to the desired pressure and open the ball valve to feed the system. As long as you have 20 psi or more coming out of the regulator it will open the wheel valves. If the tires are at 70psi and you put 32 psi into the system with the regulator it will open the valves and release the pressure from the tires and will let them drop to the set pressure you have from the regulator.

Once the system has reached the set pressure from your regulator shut the ball valve coming out of the regulator and open the dump valve to release any pressure from the system so you're not holding pressure in the wheel hubs causing more eventual wear on the hub seals.

You will still have all the options as before and many more just no longer push button. Also with this setup you can set it and run a constant pressure if you are at the shop trying to pinpoint a leak, no more controller flashing the 5 lights and not putting air in due to the leak.

 

[Blarsen]

If I may ask, where do these new parts go? can you give us a little diagram indicating what is removed and what lines to hook too? sorry in advance..
(I assume that we remove the pneumatic control valve from under the dash and replace it with this)
thanks Bret

 

[adamsoffroadperformance]

Correct. There is 2 lines into the control box on the floor one is the feed from the truck the other is the line to the ctis system. the one with the water separator is the feed in that you hook to the regulator the other hook to the outlet of the T.

 

[Blarsen]

Awesome! thanks

 

[mbent1911]

Subscribed

 

[corvette9]

How do you know the tires have reached the pressure you want, so you can shut off the feed ball valve? My 936A2 has a few tires that go low after sitting a few days . I will build this setup in a heart beat so I can just start the truck and have the tires air up. I like the simple way this works.

 

[Jbulach]

How do you know the tires have reached the pressure you want, so you can shut off the feed ball valve? My 936A2 has a few tires that go low after sitting a few days . I will build this setup in a heart beat so I can just start the truck and have the tires air up. I like the simple way this works.

With the valve labeled air supply open, when the gauge reaches the pressure you want, it's there...

 

[corvette9]

With the valve labeled air supply open, when the gauge reaches the pressure you want, it's there...

Thanks. Looks like I need to take a trip to the plumbing store. By the way. What size are the fittings? They look like 6- or 8- AN.

 

[Jbulach]

Just going off memory, I believe the two airlines that you need to cut into are 3/8" cts, and you should use DOT fittings, which you wont find at the hardware store. Check Napa, a truck shop or online

 

[corvette9]

Will do ..Thanks

 

[adamsoffroadperformance]

Just going off memory, I believe the two airlines that you need to cut into are 3/8" cts, and you should use DOT fittings, which you wont find at the hardware store. Check Napa, a truck shop or online

Yes they are 3/8"

 

[WYomer]

Yes they are 3/8"

So building one today since I'm over the trouble shooting after fixing my CTIS 5 times now.

What about going below 20psi? Do you go above 20psi to open the valves then adjust the regulator lower?

 

[Jbulach]

I think it only takes about 8-10 psi to open the wheel valves, no matter what the tires have in them. I can check my gauge and see what the working CTIS dumps at if you need to know for sure.


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[Jbulach]

If I remember correctly tire pressure in "emergency" mode is 12psi.


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[Jbulach]

I think it only takes about 8-10 psi to open the wheel valves, no matter what the tires have in them. I can check my gauge and see what the working CTIS dumps at if you need to know for sure.


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I just confirmed my factory controller holds 10 psi on the wheel valves while dumping.

I also switched to my manual system, with the regulator backed all the way off, started increasing the pressure slowly and the wheel valves started opening right at 5 psi, with 60 PSI in the tires.

 

[WYomer]

Did you use a 3/8 or 1/4 NPT regulator? Lots of 1/4 stuff but little 3/8

 

[Jbulach]

I used all 1/4", with is actually appropriately sized for 3/8" DOT tube.


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[WYomer]

Thank you!

 

[Csm Davis]

So if I want to run different pressures front and rear just separate the front and rear lines and put a regulator on each of them and leave off the regulator before the valves. Correct?

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[Jbulach]

Not sure if I follow you, but yes you could separate the front and rears, then run a tee from your supply into two regulators and four ball valves. That would actually be nice for airing down just the rears when empty!