Ehaust Brake(Pacbrake) 24v electrical interface disble

[SmokinJoe]

I have the mechanical part of the Pacbrake installed. I do NOT want the brake to come on automatically after 3 seconds of letting off the throttle. To get this desired results do I simply NOT install the wire to pin 20 on the ecm? Or will the Pacbrake just NOT work without the emc pin 20 hook up?



These are the two ways I want to use my Pacbrake:

1) Engine warm up, flip the toggle switch after starting the truck.

2) Instant on demand, push a button on the shifter when I want to slow down.

 

[SS]

Pin 20 on the ECM is to provide a delayed (1-2 sec) signal when the Throttle Position Sensor has returned to idle. If the Pacbrake has a switch and instructs you to use pin 20 then you have all you need. If you use pin 20, the exhaust brake will only activate when the switch is "ON" and the TPS is at 0%. Then to warm up engine, or brake on demand, simply throw the switch. If you choose to use another supply for power you could then use the exhaust brake even under WOT.



If it does not instruct you to use pin 20, then it may draw too much signal from this wire and I would suggest NOT to use it.



I just installed my Jacobs and had to remove the "VOID" sticker from the ECM connector. Cummins had no issue with this. Remove the 2 bolts holding the filter housing to access the ECM. Hope this helps.

 

[SmokinJoe]

Originally posted by DodgeTorqueWagon

If you choose to use another supply for power you could then use the exhaust brake even under WOT.

Are you saying that the street racers should use an exhaust brake so they can get the boost/engine spooled up???

 

[SS]

I'm saying mine's never gonna find out! If you want to try yours that way, let us know how it works out.



I'm thinking that's why Cummins provides pin 20 - bad things may happen to exhaust brake and/or engine if it's applied when it shouldn't oughta be.

 

[Thomas]

S J,



Why not hook up the electrical as Pacbrake suggests? Then you could have a period of time to decide just how bad (or good) the hookup at pin #20 of the ECM really is. If there is any cutting, etc. to install a switch in series with the pin #20 wire, you could come up with a non-destructive mounting during this trial period.



I have an E-Brake by Jacobs and assume that the electrical is essentially the same. I'm sold on the 12 volt signal from the ECM. A non-agressive driver will seldom need to use the service brakes unless they're in stop-and-go traffic or coming to a complete stop. The exhaust brake is not a substitute for the service brakes. If you need to stop fast you will use the service brakes.



I'm certain that you could activate the brake with some other 12 volt source and not hook up to the ECM. A switch at the pedal like BD or older pre-24 valve exhaust brakes use will activate the solenoid.



Whatever you do, avoid a system that will allow the brake to be on while the throttle is pushed.

 

[SS]

Thomas makes a good point. Don't cut the dash to install the switch until you're sure that's where you want it. Took me about 10 seconds of use to realize I wanted the switch on the shifter - I'm glad I didn't install the dash switch that was provided. Now it's right at my fingertips when I want to use it. The delay is not a big deal at all.

 

[klenger]

I mounted the switch on a bracket, which is mounted to the brake controller. Looks like this. It's actually quite convenient, and didn't have to cut the dash.

 

[SmokinJoe]

I know the thing works, before I put the wires inside I tested the switch with the ECU pin 20 thingy and I could get the brake to engage. Now with the wires inside the truck it is a NO GO.



Does anyone know if the 12v accessory source under the dash really is the Black wire with an Orange stripe?



I am going to test the connection with a multimeter...

 

[SmokinJoe]

Third try was a charm

Well the third black wire with the orange stripe I tapped into was the one that worked.



FWIW I dislike the auto brake feature. I would get more stopping power if I had a button on the shifter that engaged the pacbrake.



I still need to re-check the bolts on the exhaust flange and wastegate cover/adapter.



Sounds neat even with the stock exhaust...

 

[FDziurda]

Switch Location

I installed a miniature toggle switch (Radio Shack) in the lower corner, towards the driver, in the turn signal cover. Fished the wires down the inside of the steering column.



I just have to reach around the steering wheel to operate it when I want the Pac-Brake to operate. As easy as, operating the turn signal and you don't have to lean over to operate it.



Good Luck,



FDz

 

[SmokinJoe]

Re: Switch Location

Originally posted by FDziurda

I installed a miniature toggle switch (Radio Shack) in the lower corner, towards the driver, in the turn signal cover.

Did you use the pin 20 ecm wiring kit or the one with the microswitch on the throttle?

 

[FDziurda]

Microswitch

I thought about the ECM version but didn't want to wait, even a couple seconds, when I needed the exhaust brake to actuate. I have the microswitch version.

FDz