Manual CTIS, electric over pneumatic.

[Ronmar]

An automotive leakdown tester is a godsend for troubleshooting CTIS. Just remove the air line on the left side of the PCU, attach the Leakdown tester and pressure to 50 psi. Go over the air system with soapy water and a spray bottle, paying particular attention to the vents on the quick release valves.
You won't believe how many leaks you will find. The original CTIS computer will detect any leaks and fault out with all lights flashing.
Probably a good plan even if you are converting to a manual system.

Yea for regular CTIS applying air from an alternate source is the way to go to find leaks instead of waiting on the processor to Briefly pressurize it.

Another way is to disconnect the CTIS connector and jumper the 28V pin to the control solenoid and briefly jumper the 28V to the inflate solenoid to pressurize the system. Depending on how bad your leaks are, it should set there for a very long time as long as the control valve stays energized.

With the manual electric system, you are already wired to do this. With a full wet tank you should be able to feed enough pressure to open all the wheel valves 5 or 6 times with the engine off before needing to restart the truck and recharge the tank. For “shop air” I use a little pancake compressor plugged into the front emergency gladhand(Remember, this releases the parking brakes). It takes a few minutes to charge a completely empty system but is more than sufficient for most work on the truck air systems...

I start by going where my ears take me for the leaks I can hear(Engine needs to be off for this). Then I use my hands to feel for leaks. Leaks that bad often wont blow bubbles with bubblemix, they simply blow the mix out of the way. Once you get the ones you can feel and hear taken care of, pressurize it and go over it with the mix...

 

[Grond]

Yea for regular CTIS applying air from an alternate source is the way to go to find leaks instead of waiting on the processor to Briefly pressurize it.

Another way is to disconnect the CTIS connector and jumper the 28V pin to the control solenoid and briefly jumper the 28V to the inflate solenoid to pressurize the system. Depending on how bad your leaks are, it should set there for a very long time as long as the control valve stays energized.

With the manual electric system, you are already wired to do this. With a full wet tank you should be able to feed enough pressure to open all the wheel valves 5 or 6 times with the engine off before needing to restart the truck and recharge the tank. For “shop air” I use a little pancake compressor plugged into the front emergency gladhand(Remember, this releases the parking brakes). It takes a few minutes to charge a completely empty system but is more than sufficient for most work on the truck air systems...

I start by going where my ears take me for the leaks I can hear(Engine needs to be off for this). Then I use my hands to feel for leaks. Leaks that bad often wont blow bubbles with bubblemix, they simply blow the mix out of the way. Once you get the ones you can feel and hear taken care of, pressurize it and go over it with the mix...

so the only big leak I found was a wheel valve fitting and The tires are filling with air however it gets extremely slow after 50psi and I don't see any drop of pressure on the secondary gauge at all. All other systems are all operational perhaps this is normal? I haven't found any other substantial leaks thus far a bad or restricted check valve? or I am just impatient just wondering what the norm for fill up is now I guess before I start tearing into other components. what supplies the wet tank directly?

 

[Ronmar]

so the only big leak I found was a wheel valve fitting and The tires are filling with air however it gets extremely slow after 50psi and I don't see any drop of pressure on the secondary gauge at all. All other systems are all operational perhaps this is normal? I haven't found any other substantial leaks thus far a bad or restricted check valve? or I am just impatient just wondering what the norm for fill up is now I guess before I start tearing into other components. what supplies the wet tank directly?

You wont see any drop on the primary or secondary gauges. The compressor feeds the dryer, the dryer feeds the wet tank, the wet tank feeds the primary and secondary tanks thru check valves. The wet tank also feeds CTIS thru the protection valve. The only way you will see a pressure drop on the brake gauges is if you start using the brakes...

these are huge tires. I timed it once and at high idle I think it took 20+ minutes To get from 20 to 80 PSI. I think I Said earlier The wet tank drains from 120 PSI to 85 PSI in 3 seconds when you hit the inflate pushbutton. Once the wet tank gets down to 85, it only lets air out thru the protection valve as the pressure rises over 85 And the tires take it as fast as the valve will feed it. As the tires fill Above 50, the difference between the tires and the wet tank gets smaller and smaller so the flow gets slower and slower.

I found filling in pulses felt more productive I fill for 3 seconds then release the button and let the wet tank recharge for 10 then fill for 3. letting the wet tank charge to a higher pressure increases that differential pressure over the tires... I may automate this eventually using the wet tank pressure switch(closes at 115 and opens at 85 PSI) to control a relay which will fill the tires in pulses. But I need a foolproof safety to halt the fill if I forget to Being at a higher engine RPM really helps also...

 

[Grond]

You wont see any drop on the primary or secondary gauges. The compressor feeds the dryer, the dryer feeds the wet tank, the wet tank feeds the primary and secondary tanks thru check valves. The wet tank also feeds CTIS thru the protection valve. The only way you will see a pressure drop on the brake gauges is if you start using the brakes...

these are huge tires. I timed it once and at high idle I think it took 20+ minutes To get from 20 to 80 PSI. I think I Said earlier The wet tank drains from 120 PSI to 85 PSI in 3 seconds when you hit the inflate pushbutton. Once the wet tank gets down to 85, it only lets air out thru the protection valve as the pressure rises over 85 And the tires take it as fast as the valve will feed it. As the tires fill Above 50, the difference between the tires and the wet tank gets smaller and smaller so the flow gets slower and slower.

I found filling in pulses felt more productive I fill for 3 seconds then release the button and let the wet tank recharge for 10 then fill for 3. letting the wet tank charge to a higher pressure increases that differential pressure over the tires... I may automate this eventually using the wet tank pressure switch(closes at 115 and opens at 85 PSI) to control a relay which will fill the tires in pulses. But I need a foolproof safety to halt the fill if I forget to Being at a higher engine RPM really helps also...

This is definitely more insightful thank you for your response It would seem the system is fully functioning then more or less. Perhaps installing a larger tank is in order down the road or a better on board compressor.

 

[Third From Texas]

Didn't you make an upgrade to this (v2.0 )?

I've searched and come up with nada.

 

[Ronmar]

Didn't you make an upgrade to this (v2.0 )?

I've searched and come up with nada.

It’s on my youtube channel…

 

[Third From Texas]

It’s on my youtube channel…

Thanks, I thought I'd seen a re-do of it somewhere.

My controller would appear to be bricked and I'm not going to spend $$$$ going back to the OEM just to have it ever happen again.

I need to do either a manual or an Arduino and I'm leaning manual if I can sort out what I need to get how to put it all together. I still use trailer air, so I can't locate it where you did, but I can toss together an enclosure.

You have a parts list or walk thru anywhere? I track what's said in teh video but I'm not exactly sure where everything mentioned is located.

Also, can you think of anything that would need to be altered for the A1R? As far as I know, the system components are all the same except the controller itself.

 

[Ronmar]

Thanks, I thought I'd seen a re-do of it somewhere.

My controller would appear to be bricked and I'm not going to spend $$$$ going back to the OEM just to have it ever happen again.

I need to do either a manual or an Arduino and I'm leaning manual if I can sort out what I need to get how to put it all together. I still use trailer air, so I can't locate it where you did, but I can toss together an enclosure.

You have a parts list or walk thru anywhere? I track what's said in teh video but I'm not exactly sure where everything mentioned is located.

Also, can you think of anything that would need to be altered for the A1R? As far as I know, the system components are all the same except the controller itself.

I need to re-do the wiring diagram. It is pretty simple, 3switches, some diodes, a relay and a pressure gauge. I was looking at making the latch circuit with a SCR vis a relay.

I drew out a diagram for a enclosure that bolted where the original controller went, and connected re-using the connector from a dead controller…

The system is the same for an A1R. The A1R does incorporate the CTIS controller into the data comms bus. Not sure if disconnecting the data buss at the CTIS would effect the bus. I have not heard of anyone having an issues running with a dead or disconnected CTIS controller, so I suspect it would have no issues.

 

[hike]

View attachment 743103

Could you use a standard (front or rear) brake pressure gauge to read the pressure off the PCU's transducer? Desiring to keep the gauges looking uniform and wondering finding a brake pressure gauge would work. Especially, if I could redo the gauge's labeling without destroying the function.

I suppose you could swap a brake system pressure transducer in to this location if not?

 

[Ronmar]

Could you use a standard (front or rear) brake pressure gauge to read the pressure off the PCU's transducer? Desiring to keep the gauges looking uniform and wondering finding a brake pressure gauge would work. Especially, if I could redo the gauge's labeling without destroying the function.

I suppose you could swap a brake system pressure transducer in to this location if not?

You would have to use a short pigtail hose between the PCU pressure port and the gauge sender. The way they oriented the port the bottom cover partly surrounds the sensor and The 0-100 psi piezeo sensors just barely fit… you could easily fit a mechanical gauge sensor line there. Isspro is a good match for some of our gauges…

 

[hike]

You would have to use a short pigtail hose between the PCU pressure port and the gauge sender. The way they oriented the port the bottom cover partly surrounds the sensor and The 0-100 psi piezeo sensors just barely fit… you could easily fit a mechanical gauge sensor line there. Isspro is a good match for some of our gauges…

Thank you—

 

[DeMilitarized]

The Arduino controller is great and tells you exactly what issue your having rather than random lights flashing and the creator of it will troubleshoot with you over the phone and he is a great help. Definitely recommend. It also doesn't really care about air leaks.

 

[hike]

The Arduino controller is great and tells you exactly what issue your having rather than random lights flashing and the creator of it will troubleshoot with you over the phone and he is a great help. Definitely recommend. It also doesn't really care about air leaks.

I'll take a look. Thank you–

 

[DeMilitarized]

I'll take a look. Thank you–

@Plasa makes them

 

[Ronmar]

Yea Christians unit is cool, but for the ammount I will use it, 3 switches, a relay and a pressure gauge makes more sense to me... it is also nice to manually pressurize the system to look for leaks...

 

[Third From Texas]

Yea Christians unit is cool, but for the ammount I will use it, 3 switches, a relay and a pressure gauge makes more sense to me... it is also nice to manually pressurize the system to look for leaks...

I think the biggest draw to using the Arduino over building a manual controller is the fact that it's plug-n-play.

I'd have loved to have done a manual, but the more I looked at running air lines, buying all the fittings, hoses and such, the more the Arduino made sense for me. At least for the time being, it got me up and running again just plugging it in.

But as many here point out, there can be a ton of various issues that screw up the CTIS operation. Replacing the controller is just one step if the systems is being sketch. And it sounds like Hike is leaning towards a custom, manual solution anyway. I'm following to see where he takes it if he does.

 

[hike]

I think the biggest draw to using the Arduino over building a manual controller is the fact that it's plug-n-play.

I'd have loved to have done a manual, but the more I looked at running air lines, buying all the fittings, hoses and such, the more the Arduino made sense for me. At least for the time being, it got me up and running again just plugging it in.

But as many here point out, there can be a ton of various issues that screw up the CTIS operation. Replacing the controller is just one step if the systems is being sketch. And it sounds like Hike is leaning towards a custom, manual solution anyway. I'm following to see where he takes it if he does.

Really not sure as yet. I do like keeping things simple. Sometimes the simple answer may not be the simplest solution.

Running line, adding some momentariness and a gauge would fit into my plan to redesign the cockpit dash layout into something more ergonomic and functional.

I haven't seen the cost of @Plasa unit, nor all the functionality.

When I use @Ronmar wire jumping trick to make sure the rest of the system works a plug and play solution would be very nice and allow me to move onto other repairs and projects on my LMTV todo list.

It is a fun journey–

 

[coachgeo]

Really not sure as yet. I do like keeping things simple. Sometimes the simple answer may not be the simplest solution.

Running line, adding some momentariness and a gauge would fit into my plan to redesign the cockpit dash layout into something more ergonomic and functional.

I haven't seen the cost of @Plasa unit, nor all the functionality.

When I use @Ronmar wire jumping trick to make sure the rest of the system works a plug and play solution would be very nice and allow me to move onto other repairs and projects on my LMTV todo list.

It is a fun journey–

just search " Arduino CTIS " and you will find Plasa threads on his unit.

 

[hike]

So, today I confirmed the CTIS system works, just the ECU is bricked (5 steady lights). Time to look into Arduino CTIS system and decide whether manual mod or plug and play is simplest solution.

I appreciate everyone's help and not getting flamed returning to an older post. Thank you all—

 

[hike]

In the end I decided to try plug and play and wanted to have a spare so I have ordered an Arduino unit and found a new in the box Dana. So, we will try both and see how they compare–