Newbe 931a2 ctis

[Desertshark]

So first I am very new to this truck and the big green addiction also... Have gone thru a lot of the TM's on the subject.... I suffer from 5 blinking lights.
Things I have done replaced the ecu the PCu and searched for leaks. I also have bumped the pressure up to 135 lbs.i hear it try to cycle every 30 seconds or so. I hear something like if the reared is locking up or testing and that's it.... I would really love to keep my ctis but am slowly getting at the end of my rope. Any help or good schematics would be extremely greatfull .

 

[98G]

Disable it now, or disable it roadside some day when it deflates all your tires and refuses to reinflate...

In all seriousness, there's probably a leak you haven't found or a sensor malf. Try pressurizing it with a portable compressor so you won't have engine noise, and also happy hunting with a squirt bottle of soapy water.

 

[Desertshark]

That's why got smart and have an airline and chuck connected with a glad hand . But I guess the soapy water bottle and I will hunt some more... now just got to wait for a day not windy to do it.

 

[silverstate55]

With 5 flashing lights it's most likely a leak at the wheel end...such as a valve core, hose/hose end, or wheel valve.

Please tell me that you've rebuilt the air dryer, or installed a new one before trying to get the CTIS to work...I've noticed that a lot of these systems don't work due to moisture getting in them from a tired/over-worked air dryer, and by sitting for long periods of time, allowing the moisture to corrode the insides of the wheel valves and whatnot.

 

[Suprman]

Rear wheel valves slip up ftom the hub stem. It's a bad design. You need someone at the wheel to listen for air leaks when the system is pressure testing. If you hear a siren sound then it's a bad hub seal. You should also check and make sure someone didn't block the system off with schrader valves in the stems. If you can add or release air from the valves on the wheel valve then the stems are clear.

 

[98G]

That's why got smart and have an airline and chuck connected with a glad hand . But I guess the soapy water bottle and I will hunt some more... now just got to wait for a day not windy to do it.

Yeah, I had an air line with a glad hand also. CTIS dumped all 6 tires to 17psi at the entrance gate to Ft Riley. I stopped and manually aired them back up and it dumped them again..... no more CTIS for me

 

[Suprman]

A bad hub seal will do that. It tricks the mechanical valves into thinking its air dump time by diluting the fill air pressure sent by the controller/cab valve.

 

[Desertshark]

I have not rebuilt the air dryer. But had been thinking of buying new updated one... now it seams like a good idea. The stems are not blocked I can add and deflate manually. No honk sound so seals should be good.... guess the next thing I will try is the air dryer.

 

[Suprman]

The air dryer is good to change or service. It is not causing your ctis problem though. If the system starts with hwy flashing and when you have around 120psi it does the pressure check and you get 5 flashing lights the system is probably detecting a large air leak. Check the rear wheel valves where they mount.

 

[Desertshark]

Suprman that is exactly what it is doing. And then it makes a sound like if reared is locking up.

 

[Suprman]

It does the pressure check and then a quick vent out the release valves. A leak is detected. Put your hand on each of the rear wheel valves. They are pressure held on a stem coming out of the hub. The bracket dosnt do much for them. Centrifugal force pulls them off the stem and you have an air leak. But its hard to tell by just looking at it.

 

[Desertshark]

Ok well when I get home I will take thoes covers off and hit it with some soapy water spray bottle and see. If I can find an air leak...

 

[Suprman]

You can reach your hand right up to the stem

 

[Desertshark]

Ok I will check it out when I get home in a few hours and let you know

 

[Desertshark]

So update. First I ordered a new air dryer. I found what was making noise in the back. I called it the farting duck bill.... I belive it is a dump valve.. the 2 in rear work. Was not able to find one for the front. Also unable to check for air coming from valves. Evening winds picked up and killed that idea early.

 

[Tracer]

We have an Oshkosh fire truck where I work, and last year the CTIS dumped all 6 tires and we were without a fire truck for a couple days. Chuck it!

 

[adamsoffroadperformance]

mine acted the same and found the valve cores moved into the wheels. it would blow a little bit gear oil out of the Schrader on the ctis valve. I moved the valve cores out to the valve from the wheels and tried it and it blew gear oil out of the farting duckbill. so I put new seals in the rear wheel hub and new orings in the valves on the front wheels where they bolt to the drive flange. works great now. and my computer is a brand new computer that was installed before I got the truck.

 

[silverstate55]

So update. First I ordered a new air dryer. I found what was making noise in the back. I called it the farting duck bill.... I belive it is a dump valve.. the 2 in rear work. Was not able to find one for the front. Also unable to check for air coming from valves. Evening winds picked up and killed that idea early.

The front valve is ahead of & below the radiator.

 

[Desertshark]

Well have a good friend of mine order 6 new wheel valves ..... my price 65. Bucks for all 6.

 

[Desertshark]

So today I got my new air dryer and installed it . But as I got pressure up and checked on things I . I went to front to look and hear farting duckbill. Well there is a air valve there but no duckbill ....