M1078 fmtv ctis

Pointman0853

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So If I have 5 continously blinking lights, I should check the pressure in the third tank? I have already cleaned all of the connectors and used di-electric grease. Still 5 blinking lights. I guess I'll bump up the govenor. Dash gauges show 120 psi..

Pointman
 
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this is awesome, I will try this also, the photos are great!!! But where is the connectors at the manifold located?

Thanks
Seth







Ok, My CTIS is working again. Here is a rundown of what I did. First and foremost I had to identify the pressure
switch that everyone was talking about. Mine is right above the CTIS supply line on the wet tank.
View attachment 585146

I then separated it and marked it with red dots for aligning it so I could connect it and disconnect it really fast several times after applying cleaner and then the Dielectric grease.
View attachment 585149 View attachment 585150 View attachment 585151

I then did the same on the connectors at the CTIS controller and the connectors at the manifold. Here are also photos of the products that I used.
View attachment 585153View attachment 585154View attachment 585155 View attachment 585158
 

coachgeo

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i had to in-cease the air pressure turning the screw on the air pump on the engine and once the pressure was up the CTIS worked
wonder if need to increase pressure by turning up pump may be needed to compensate for wear within the pump allowing it to not be pushing as much air as once could..... or if increased pressure compensated for air loss from leak(s) elsewhere. Very interesting.
 

Masspilot

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My ctis only deflates I press the buttons to change modes and nothing happens. I have changed out controller and still same thing
 

ghog50cal

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Marietta ok
I am having a similar but different ctis issue my lights don't flash stay sold changes too all settings but nothing happens with tire pressure
 

Ohiobenz

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OK, to keep things in a similar thread...
My CTIS controller has no flashing error lights.
The air appears to be at 120 on both gauges (haven't checked the tanks).
When I switch from HWY to SAND nothing happens except the light on the display.
The tires were manually inflated to 55psi, and all but the left rear are still at that pressure.
I removed the quick release valve but it is plastic and doesn't look like it can be disassembled.
Any suggestions.
 

Ohiobenz

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No deflation CTIS

Kinda hard to interpret what you are trying to tell us!?
It sounds like his CTIS is doing the same as mine.

Today I checked the tank pressure switch and when the gauges read 120psi the switch is closed.

I removed the front QRV and with the truck running and CTIS on "HWY" there is no air coming out of the feed hose. There is also no air coming out of the lines going to the wheels/hubs. I would think that the controller should send a pulse of air every 5? minutes?

I got sidetracked with a fan clutch air leak so other than putting dielectric grease on the pressure switch and CTIS controller, I didn't get any further.
 
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Coffey1

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Take pcu apart and clean and check all solenoids.
I have found this is a large problem the solenoids burned out or the tiny holes the air goes through clogged
Have yet to run into a bad pressure switch or transducer
Be careful if you remove transducer from pcu they will snap off when trying to unscrew them.
 

Coffey1

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I can't remember if they are 12 or 24 on fmtv.
What you want to check is continuity of the coil.
 

tennmogger

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It sounds like his CTIS is doing the same as mine.

Today I checked the tank pressure switch and when the gauges read 120psi the switch is closed.

I removed the front QRV and with the truck running and CTIS on "HWY" there is no air coming out of the feed hose. There is also no air coming out of the lines going to the wheels/hubs. I would think that the controller should send a pulse of air every 5? minutes?

I got sidetracked with a fan clutch air leak so other than putting dielectric grease on the pressure switch and CTIS controller, I didn't get any further.
The gauges for the dry tanks can be misleading because they do not indicate the pressure in the wet tank (where CTIS air comes from). Such conditions as too-low idle, leaks past the Over Pressure Valve (which comes off the wet tank) or a leaking OPV itself can drop wet tank pressure without any indicator.

Your measurement of the switch closure IS a good test though, and high-enough pressure is indicated in the wet tank. But there's another 'gotya'. If the OPV is set at a high enough pressure it can fail to open even if the wet tank switch says "ok". If the OPV leaks it can also fail to pressurize the CTIS. So the pressure out of the OPV is something to check. Without pressure out of the OPV the CTIS controller has no pressure to work with even if the pressure switch is closed (like yours is).

The CTIS only checks pressure every 15 minutes and that can seem like a long wait.

BTW, the fan's clutch control pressure is also reliant on the OPV so if your fan is on all the time, that's a good diagnostic tool.
 

Ohiobenz

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Tennmogger, Thanks for the additional info.
Its interesting that you mentioned the fan clutch since I heard a new air leak yesterday when just turning power on, but not starting. Turned out the last motorpool guy had tightened the bottom fitting so the hose was rubbing. It finally wore through...
When driving the truck earlier the fan clutch definitely worked! Kind of hard to miss lol.
So with that info do you think the OPV is ok?

As an aside... I would love to see Admin set up a folder for all CTIS threads to go into...
 

coachgeo

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...As an aside... I would love to see Admin set up a folder for all CTIS threads to go into...
pretty sure 99.9% of all "bulletin board software" that is the engines of most of these discussion boards; like Steel Soldiers, does not have the capability of creating deeper set of "sub forums/folders" such as your suggesting. Wish like heck they did.
 
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Ohiobenz

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Not sure that I agree.
Under "current conflict vehicles" there are a number of "folders". It would simply require adding a "CTIS" one.
 

coachgeo

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Not sure that I agree.
Under "current conflict vehicles" there are a number of "folders". It would simply require adding a "CTIS" one.
ahhhh.... different animal that what thought you were suggesting. Was under impression you were referring to ctis sub forum/folder under the FMTV forum.

So your idea is not a bad one and could be done.... though am curious if a seperate CTIS discussion forum under "current conflict vehicles" would help or not though??? Are the CTIS systems on the different "current conflict vehicles" potentially just NOT similar "enough" to be able to be able to compare troubleshooting, repair etc. I don't know the answer to that .... curious to hear from others whom have enough experience in the various vehicles ctis systems have to say on this.
 
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