M923 CTIS problem

[plowboy]

The CTIS diagnostics are in TM9-2320-272-23-1

 

[BKubu]

Guess I'm lucky then Murco, Mine works fine with 30K miles on the truck. Great I just jinxed myself.

I had an M35A3 with working CTIS...until it failed after about six months. I recommend using it often (at least monthly) as I have heard that sitting is one of the biggest problems.

 

[Burney]

Can i install regulator???

I just got my M923A1. Can I put a air regulator under the dash? I will not be using it much but I don't want to keep trying to figure out what air leak I have each time I use it or show it off. My CTIS REGULATOR IS MISSING, I still have the hwy, mud, sand buttons AND I want to make sure the tires are ready each time I drive her. I could place a value on the input side of the regulator and if I need air. I can adjust the regulator to 80psi or 10psi..
Or if I need to I can put an inline value on each wheel.
What do you think guys?? Help me decide my next move.
Thanks.. looking for both good advice and criticism.

 

[Suprman]

Well if you have a ctis control you have an a2. The valve body controls inflation and deflation if it was missing you would have to find one used. You can manually inflate your tires do they go flat over time or hold pressure? There are valves on the rims. You can bypass the wheel valves a standard schrader wheel valve will screw into the stem piece coming off the rim you have to remove a hose to do it. You will have a bumpy ride at 80 psi. Post pics of the dash area.

 

[1 Patriot-of-many]

I just got my M923A1. Can I put a air regulator under the dash? I will not be using it much but I don't want to keep trying to figure out what air leak I have each time I use it or show it off. My CTIS REGULATOR IS MISSING, I still have the hwy, mud, sand buttons AND I want to make sure the tires are ready each time I drive her. I could place a value on the input side of the regulator and if I need air. I can adjust the regulator to 80psi or 10psi..
Or if I need to I can put an inline value on each wheel.
What do you think guys?? Help me decide my next move.
Thanks.. looking for both good advice and criticism.

Are you joking? If you have CTIS, it's an A2. A1's have the same tire size as the A2, but none of the CTIS hardware.

 

[Burney]

Wow an A2

It was listed as an A1 in the GL auction.
Since I am new and learning the ropes. I
Probably need all the help I can get. I read
many of the post but it will take me a while
to navigate the site. But I am very happy to
know there are ppl who can help.
I am at work but will send photo tomorrow.

Yes the tires go down over night, all of them.
I temporarily placed a manual valve between the
Lines under the dash. I unplugged the ECU.
I OPEN THE VALUE to inflate the tires..Is this wrong?
When the tires are 50 psi I close the value..
Can you tell me where I might can find an
CTIS? I WOULD like it in orignal working
condition but I just don't know who has
Parts ..
thanks

 

[markmontana]

I think we need to see more pictures --- then we can give you better help and advice (free however!)

Sounds to me like we have some translation problems we need to fix.

Welcome to SS, too!

 

[Suprman]

Even with the valve body missing your tires should not deflate. Air them all up and listen to see where the air is leaking out. Sometimes the lines are not on tight enough or the need an o ring here and there. If the valves are bad it could be leaking out thru there also. Get some windex and start spraying you will see bubbles where the air is leaking. Do not overtighten hoses if air is leaking and the hose feels tight you will want to replace the o ring if it is even there. You can get a generic o ring kit cheap they work just fine. You can also get valves or rebuild kits for them its just a spring and rubber diaphragm in there. Sometimes taking them apart and cleaning them works. The valve body will not stop your tires from going flat overnite. You must have pretty big leaks though usually it takes a few days for them all to go flat. If you can iinflate them all from the air line that would have gone to the valve body that is actually a good sign all the lines are there and connected. There should be 2 lines that went to the valve body the other is the air supply I would plug that one for now. You don't want the truck sitting on flat tires it can cause internal damage to the tires and make them prone to blowout.

 

[1 Patriot-of-many]

Well from what you're describing you have all the hardware to the tires. You have a dataplate on the right side of the dash, no doubt it says A2. You have a lot of reading to do in the TM's. TNJmurray has parts for the A2. Pictures would be good.
That's really strange that all the tires are going flat though? They all have individual valves on the wheels. Kinda hard to believe they all have bad orings or leaky connections. Honestly I don't know a lot about my 5 ton myself, but I understand my M35A3 CTIS quite well, thinking it's pretty much the same principals.

 

[Suprman]

There is an air feed to the valve body it had 3 air valves in it all are controlled with electric solenoids and it has a pressure sensor on the body. Each wheel has a "semi-one way" air valve so the system can add pressure to the tires and it shouldn't leak back out. I believe there is a air valve between each pair of tires left and right it is called a quick release valve. All 3 release valves are fed thru the line off the main valve body in the cab. If your front left tire is low and the rest of the tires are aired up, when the system feeds in air for let's say highway mode which is the default. It is 60 psi I believe, as air is feeding in, the wheel valves will open from the fed pressure. The low tire will take in air the ones that are full to 60 psi already will not take in more pressure since their pressure is equal to the feed pressure. Now to let air out. The valve body sends a steady 12 psi to all wheel valves and quick release valves which all open and allow air out and down goes the pressure. If you go all the way down to emergency mode and the tire pressure gets too low the system may not be able to air up the tires it might need help you can manually air up a few tires and the system will take over from there. When the pressure is too low to air up the air that the system is trying to feed in will just come out the quick release valves. I think the tires need to have a certain amount of pressure to keep the quick release valves closed.

 

[HASSON1911]

So i know this is about 5 lights, but mine has 4 flashing (except emergency). Book says a vavle is malfunctioning. and its correct I hear it build pressure than it just blows, but I can't find it. Is it possible its the one in the cab. that's were it sounds like it coming from. I would assume it has the possibility that it can be anyone though. Does this sound correct to someone?

 

[Suprman]

It sounds like you have an air leak on the fill side. It sounds like the system is trying to check pressure or add pressure and is detecting a leak. Its probably not a wide open leak or you would get all 5 lights flashing. The noise you hear is normal its when the system stops sending pressure the quick release valves do a slight dump. You need to have someone press the hwy button while you walk around the truck listening for a leak. When the hwy button is pressed the system will send air to check pressure and then fill if needed. If there is a leak you should be able to hear it if you are close to the leak even with the truck running. Check the valve areas and lines that go to the quick release valves they can dry rot follow them along. Each axle had a quick release valve the front one is behind the first front crossmember. With the older style rear tire valves they are held on by a bracket and a rubber friction fitting this can come loose. There are also seals in the wheel hubs the ctis air passes thru there I understand the seals can wear out I believe the military replaces them on a yearly schedule but I have no experience with them. Do your tires go flat every night or every few days? Is this a new problem or you got the truck like that?

 

[HASSON1911]

It a new truck had it bout a month, the ctis just gave me a hiccup about week ago, it was corrected by restarting the ctis but that trick hasn't worked this week . There is only one tire that gets low after about 2 weeks sitting. I guess I'll start listening around there? I pray for me and the truck its not an axle seal. Other wise Im going to have to disconnect it, can't afford those seals!

 

[Suprman]

The tire going low will not be caused by an axle seal. Bring the tire up to full pressure take windex spray the metal tube coming off the rim follow along to the valve spray all joints if no leaks there then it's the valve or the rim seal or the tire seating but the valve will be the most likely culprit. You can take it apart there is a spring inside its not under much pressure just don't let it go flying when you open it. You can order a rebuild kit or try to clean it up and see if it works. Valves are available there are 2 kinds some trucks have combinations of the 2 valve styles.

 

[HASSON1911]

Couldnt find it today must be slow leak, but the ctis did start working. Another question somewhat related to ctis. does each tire need a counter weight I have a tire that either never had one or somehow fell off. there isnt a vibration in my truck till about 55 but from 55 to 60 is does get pretty bad. Also, where can I even buy these weights?

 

[Suprman]

The front tires each have a counter weight the rears do not. You need the front counterweight or that vibration can eventually cause wear and damage. Sometimes you have to run the ctis system up and down. Don't go to emergency mode unless you have an air source or glad hand fill hose. If one or two tires are flat and the rest are full the system can air them up. If you let them all down low even if the system does it, if the pressure overall gets too low the system will not be able to air them back up without help. You will hear the system sending air but it will just dump out the quick release valves. If you air up one side of tires to around 40psi the system will kick in and bring them all up. It does take a little while when just idling.

 

[1 Patriot-of-many]

Couldnt find it today must be slow leak, but the ctis did start working. Another question somewhat related to ctis. does each tire need a counter weight I have a tire that either never had one or somehow fell off. there isnt a vibration in my truck till about 55 but from 55 to 60 is does get pretty bad. Also, where can I even buy these weights?

I have the same issue. 55 It shakes like the death wobble on my deuce. Do you have one tire that's worn more than the rest? My left middle axles tire has much more wear and the spare is worn down like it was dragging and replaced with the current tire. I caged the brake, but no difference to speak of. Guess I need to grease the U joints then move onto checking the bearing.

 

[Suprman]

Maybe you have a bent rim. Swap the wheels with the back axle see if the problem moves. Is the spare rim on the truck now I don't believe the spare rim has ctis on it.

 

[HASSON1911]

Nope all my tires are brand new and still have molding marks. The only thing I can see different is that dumb counter balance on the front tire, I want to get one and see if that solves anything, as I should have it to begin with!

 

[Suprman]

No weights on rear tires. If you are missing one on a front tire you need to replace it. That will cause your vibration. Post a pic of the wheel you are referring to.