Need help with CTIS system

[firestomper]

The Volunteer Fire Dept. I belong to just recived a 1995 M353A from the State Forest Fire Service. I need help with the CTIS. when you power the unit up I hear something clicking under the truck. The unit on the dash says no manifold pressure then it says flat. any ideas.

 

[sierra117]

It could be that it is to cold for it function. Mine does something similar until it has ran for a while.

 

[Rustygears]

The clicking is the unit puffing on the plumbing to open the wheel valves to sense pressure of the wheels. If the unit cannot pressurize the system to about 15 psi, the valves won't open and will read flat since there is no tire pressure filling the line after the puff. The usual issue is either a disconnected system (plumbing cut) since many trucks had the CTIS disabled for GL sales or else a fitting somewhere downstream from the manifold to one one of the wheels is loose, plastic line cut, etc.

More rarely, the manifold is gummed up with oil & snot from a poorly serviced air dryer and/or a bad seal at a hub.

Make sure you follow ops TM and don't try running CTIS without running the truck for a couple of miles to seat the hub seals. Otherwise you Risk blowing them out and that is an expensive and nasty repair.

Search for my other posts that describe in minute detail exactly hw CTIS works on the A3 and how to troubleshoot. It is a really simple system.

 

[goodguyzy]

Just leave it off.

 

[YOUNG GUN]

I contacted CM Automotive and they have been VERY helpful.

They rebuilt my manifold, and a wheel valve because they had oil in them.
Apparently the oil damages the diaphrams.

 

[firestomper]

Thanks for the info

 

[trukhead]

Actiovating CTIS in the cold while remaining stationary

It's 1-20* here depending on the day. I have a front wheel that goes flat. I corrected a bad line to the left front wheel.
Yesterday I started up the engine and fast idled it and inflated the leaking wheel in about 2 minutes. I did not move the truck so are the wheel seals in jeporady in the cold if the wheels don't turn? Didn't mean to hijack the thread but why start a new one?

 

[YOUNG GUN]

The CTIS should not be operated at temperatures below 0 Deg F, and I believe at cold temperatures above 0 Deg F it's supposed to be driven several miles before activating the system.

I could be wrong on the last part, but the 0 to -65 F is in the TM.

 

[bbf]

i have never had a luck with that system i

 

[Deuce007]

My deuce does that same thing and what I do is hit the start button on the CTIS control panel then a few seconds later it will say "FLAT" then I hit the start button twice more until it says "adjusting pressure system" then it will put a little air in the tires and keep doing these steps until it reaches about 15 psi and it will automatically air up.

 

[Floridianson]

Mine has never worked and the air line was disconnected from the air tanks.

 

[YOUNG GUN]

This is a little off topic, but here it goes...

Why do so many folks on here dislike the CTIS?

I realize it typically has some issues when pulled off a GL lot, but don't you think it's from lack of maintenance, sitting for who knows how long, etc.?

I for one bought my truck with the understanding that it would probably have some issues that would need to be addressed, the CTIS being one of them.
Even if my CTIS would have worked properly from day one, I still would have gone through the whole system to make sure everything was in good working order, just like I'm currently in the process of going through all of my wheel bearings, inner axle seals, etc.

I may be a little anal about my toys working properly and giving me many years of trouble free enjoyment, but it seems like so many just call it a piece of crap system, and say take it off or disconnect it.
I'm sure others have had more severe issues than mine, but am I missing something?

Also, before someone says "well, are you going to take your engine apart as well?"
I'm just talking about the issues that require nuts, bolts, time, and relatively inexpensive parts that almost anyone can replace/repair.

Just a thought, I'll stop now.

 

[trukhead]

I got Trucky (the A3-rymhes with Chucky) 2 years ago and I had no idea of moisture in the air system, then 5 days ago I figured out that those 3 drains needed servicing. I proceeded to drain THE FIRST ONE AND WETNESS OF YUCKY PROPORTIONS CAME OUT! I them proceeded to work the next 2. I had to poke wire in there to get the snot and yuck to come out. I ordered a haldex kit from a SS member here from escrew. I sent him cash and kit came in mail today. totally righteous fellow!

Any way, My CTIS has worked from Day 1 in spite of the neglect and snot in the system.

I experienced the same flat message a few times, but Trucky and I had a butting of heads and I kept on insisting it inflate and by some fluke it did. To this day it functions. I am trying to learn more about it and have discovered reading the TM's.
The Tms's are interesting readiing.

 

[goodguyzy]

If mine ever worked I would never use it anyway. I run 55psi in front and 50psi in rear. If I ever took it to the dunes or whatnot its faster to manually air up and down. I would never trust the system to properly inflate my tires anyway, I want to see the gauge reading for myself.