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Pacbrake Install - ECM Signal

Tambs
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Tambs

Tambs

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I installed a Pacbrake C44064 inline exhaust brake and it works great.  Except for the brake, that is.  Compressor works as it’s supposed to, supplying air to the quick-connect and Packbrake air tank.   When I flip the switch on the shifter mounted brake switch the solenoid on the compressor does not supply air to the brake.  
 

The solenoid on the compressor that supplies air to the brake cylinder does cycle when I apply 12V to it direct from the battery via a jumper wire, so I checked for voltage to ground coming from Pin 20 on the ECM while the truck was running at idle.  No voltage was present.   Any ideas why this pin isn’t energized at idle?   I’m in the midst of resetting the TPS per Mike’s YT video, so maybe that might help.  Will update after the reset is done.   
 

Any ideas?

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Tractorman

Tractorman

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2 hours ago, Tambs said:

so I checked for voltage to ground coming from Pin 20 on the ECM while the truck was running at idle.  No voltage was present.

 

I may not be able to help much here, but if you answer some questions, others may be able to help.

 

Is the air solenoid for the PacBrake valve controlled by a relay?

If so, is it your intention to have the ECM wired to the coil of the relay so that the ECM determines when the engine is at idle and allows for the exhaust brake to work?

Does PacBrake provide detailed information (such as theory of operation) as to how the system is intended to work?

 

I don't know what Pin #20 from the ECM's job is.  I just went through my factory service manual wiring diagrams and I did not find pin #20 from the ECM -  I could have missed seeing it, though.

 

This site provides wiring diagrams for your truck.  They should be available to you.

 

- John

 

 

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Mopar1973Man

Mopar1973Man

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As for both of my trucks...

  • 2006 Dodge Ram 3500 with a BD exhaust brake. You can toggle on the exhaust brake and the compressor fires up and closes the valve at a idle. This truck has auto exhaust brake so if your target speed is being exceeded then the exhaust brake comes on. Warm up it will hold the exhaust brake closed till 170*F then it opens automatically. 
  • 2002 Dodge Ram 2500 with a Jacobs exhaust brake. You can toggle on the exhaust brake and the vacuum is applied and closes the valve at a idle.

But anyways both trucks are capable of closing the valve at an idle. As for the air supply you need a reservoir tank. Then the compressor will automatically fill the tank and then shut off when the pressure is high enough. Then you have plenty of air supply for tires or other things. 

 

Yup I've got to install this 2.5 gallon tank on a BD exhaust brake on a Duramax this weekend.

20210422_163948.jpg

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IBMobile

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After reading the installation instructions pin #20 is not used and left blank in normal operation, that's why it doesn't show up in the FSM.   

I see only three thing that could keep voltage from that wire: 

  1. Throttle switch not closed.   You've checked and readjusted it.
  2. Poor or improper connection at #20 connector.  I'm sure you rechecked the installation of the terminal into pin #20 and the sealing pin didn't get pushed into  the ECM connector.   
  3. An uncooperating ECM.

One other thing about the Pacbrake is the lubrication that is called for.   I pulled up the MSDS for the Pacbrake SuperLube and Super Lube Oil w/PTFE is what came up.  

You can buy the 4oz bottle of Pacbrake  SuperLube exhaust brake lube for $17-$30 on eBay or a 32oz bottle of Super Lube Oil w/PTFE for $16.16 at the Home Depot and three 4oz plastic bottles at a craft store for $2. 

 

 

 

 

 

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Tambs

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4 hours ago, Tractorman said:

 

I may not be able to help much here, but if you answer some questions, others may be able to help.

 

Is the air solenoid for the PacBrake valve controlled by a relay?

If so, is it your intention to have the ECM wired to the coil of the relay so that the ECM determines when the engine is at idle and allows for the exhaust brake to work?

Does PacBrake provide detailed information (such as theory of operation) as to how the system is intended to work?

 

I don't know what Pin #20 from the ECM's job is.  I just went through my factory service manual wiring diagrams and I did not find pin #20 from the ECM -  I could have missed seeing it, though.

 

This site provides wiring diagrams for your truck.  They should be available to you.

 

- John

 

 

Solenoid is controlled by a relay.  Relay is controlled by sensing voltage from Pin 20 (per Pacbrake instructions). 
 

And yes, the brake relies on idle being sensed before activating (or idle throttle position anyway).   Pacbrake instructions detail this as the method of operation.   For this method of install anyway.  They offer an ECM bypass switch that runs off of a micro switch set to close when the throttle returns to idle (similar to how engine brakes in semi trucks are switched on the throttle pedal and clutch pedal).  I have one of these switches but wasn’t going to install it yet.   Probably going to have to since Pin 20 is dead.  
 

 

2 hours ago, Mopar1973Man said:

As for both of my trucks...

  • 2006 Dodge Ram 3500 with a BD exhaust brake. You can toggle on the exhaust brake and the compressor fires up and closes the valve at a idle. This truck has auto exhaust brake so if your target speed is being exceeded then the exhaust brake comes on. Warm up it will hold the exhaust brake closed till 170*F then it opens automatically. 
  • 2002 Dodge Ram 2500 with a Jacobs exhaust brake. You can toggle on the exhaust brake and the vacuum is applied and closes the valve at a idle.

But anyways both trucks are capable of closing the valve at an idle. As for the air supply you need a reservoir tank. Then the compressor will automatically fill the tank and then shut off when the pressure is high enough. Then you have plenty of air supply for tires or other things. 

 

Yup I've got to install this 2.5 gallon tank on a BD exhaust brake on a Duramax this weekend.

20210422_163948.jpg

Yep, reservoir is installed, as is the quick connect for filling tires, etc.  All that part works fine.  It’s the ecm that isn’t sending the signal to pin 20.  

1 hour ago, IBMobile said:

After reading the installation instructions pin #20 is not used and left blank in normal operation, that's why it doesn't show up in the FSM.   

I see only three thing that could keep voltage from that wire: 

  1. Throttle switch not closed.   You've checked and readjusted it.
  2. Poor or improper connection at #20 connector.  I'm sure you rechecked the installation of the terminal into pin #20 and the sealing pin didn't get pushed into  the ECM connector.   
  3. An uncooperating ECM.

One other thing about the Pacbrake is the lubrication that is called for.   I pulled up the MSDS for the Pacbrake SuperLube and Super Lube Oil w/PTFE is what came up.  

You can buy the 4oz bottle of Pacbrake  SuperLube exhaust brake lube for $17-$30 on eBay or a 32oz bottle of Super Lube Oil w/PTFE for $16.16 at the Home Depot and three 4oz plastic bottles at a craft store for $2. 

 

 

 

 

 

1.  I’ve done the TPS reset as shown in Mike’s YT video.  Other than that I’m not sure yet what else to do to verify the TPS sensor is working.   
 

2. Yes, I’ve triple-checked that the pin is seated into socket 20.   
 

3.  Possibly, but hopefully not.  🥴

 

I have the oil for the brake but that isn’t the issue.  When I manually apply voltage to the solenoid it activates and air is supplied to the brake cylinder, and then the brake butterfly  closes.   

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Tractorman

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1 hour ago, Tambs said:

They offer an ECM bypass switch that runs off of a micro switch set to close when the throttle returns to idle

 

I am curious as to where that switch would be mounted (just for my own information), whether it is at the throttle in the cab or by the APPS in the engine compartment.  I have an older style vacuum operated PacBrake that I  wired in myself.  I did not use a throttle switch or a clutch switch.  I relayed the solenoid valve and the relay is operated with a momentary foot switch that I mounted on the floor right beside where my left foot rests.  This setup makes it not very likely to operate the throttle and the exhaust brake at the same time. However, if the PacBrake micro switch would be a reliable setup, I would be interested in mounting one in my truck.

 

Let us know how you resolved your problem.

 

- John

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Tambs

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44 minutes ago, IBMobile said:

This was just a heads up of where you can get the same oil for cheap.

Thanks for the heads up.   Pacbrake is awfully proud of their stuff.   

19 minutes ago, Tractorman said:

 

I am curious as to where that switch would be mounted (just for my own information), whether it is at the throttle in the cab or by the APPS in the engine compartment.  I have an older style vacuum operated PacBrake that I  wired in myself.  I did not use a throttle switch or a clutch switch.  I relayed the solenoid valve and the relay is operated with a momentary foot switch that I mounted on the floor right beside where my left foot rests.  This setup makes it not very likely to operate the throttle and the exhaust brake at the same time. However, if the PacBrake micro switch would be a reliable setup, I would be interested in mounting one in my truck.

 

Let us know how you resolved your problem.

 

- John

I’m currently camping but once I get home I’ll post the instruction sheet.  The switch gets mounted to a stud on the firewall inside the cab.  The switch is adjusted to close when the throttle is released.   It is wired into the on/off switch, and a wire to the solenoid relay.  I’m thinking I’m going to have to abandon the ECM activation method (pin 20 per Pacbrake’s instructions) and go with the ECM bypass (throttle) switch.   I’ll probably add a clutch switch as well so that when either pedal is depressed the brake is not activated.  

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Tambs

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13 minutes ago, IBMobile said:

I finished the installation of a Pacbrake C44075 last week and found their instructions woefully lacking and some times clear as mud.     

 

Here is the link for the oil at Home Depot.

https://www.homedepot.com/p/Super-Lube-1-qt-Bottle-Oil-with-Syncolon-PTFE-Lubricant-51030/202932721?

Amen to that.  They were horrible instructions.  So vague.   
 

Thanks for the link.  

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Blueox01

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18 hours ago, Mopar1973Man said:

As for both of my trucks...

  • 2006 Dodge Ram 3500 with a BD exhaust brake. You can toggle on the exhaust brake and the compressor fires up and closes the valve at a idle. This truck has auto exhaust brake so if your target speed is being exceeded then the exhaust brake comes on. Warm up it will hold the exhaust brake closed till 170*F then it opens automatically. 
  • 2002 Dodge Ram 2500 with a Jacobs exhaust brake. You can toggle on the exhaust brake and the vacuum is applied and closes the valve at a idle.

But anyways both trucks are capable of closing the valve at an idle. As for the air supply you need a reservoir tank. Then the compressor will automatically fill the tank and then shut off when the pressure is high enough. Then you have plenty of air supply for tires or other things. 

 

Yup I've got to install this 2.5 gallon tank on a BD exhaust brake on a Duramax this weekend.

20210422_163948.jpg

What this tank cost? My PB came with .5 gallon tank.

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