Exhaust brake question

[Bug Out]

After having the CP4 swapped out and new pump installed I have noticed My power/fuel mileage is the same but one big difference is my exhaust brake does not work nearly as well as it did. I used to be able to use my exhaust brake going down hill with cruise on and it would put out LOTS of braking HP. It would usually keep me within 5-6mph of the set MPH on cruise. Now, it free wheels and yesterday cruise set at 60MPH the truck ran up to 77 mph..I had to turn cruise off to get it to slow me down. Tried both full and auto brake. No difference.

Are the e-brake parameters all the same or different for various GCVWR etc?

 

[SnoKing]

After having the CP4 swapped out and new pump installed I have noticed My power/fuel mileage is the same but one big difference is my exhaust brake does not work nearly as well as it did. I used to be able to use my exhaust brake going down hill with cruise on and it would put out LOTS of braking HP. It would usually keep me within 5-6mph of the set MPH on cruise. Now, it free wheels and yesterday cruise set at 60MPH the truck ran up to 77 mph..I had to turn cruise off to get it to slow me down. Tried both full and auto brake. No difference.

Are the e-brake parameters all the same or different for various GCVWR etc?

Time to take it back to the dealer!

 

[endoscott]

That doesn't seem right at all. Warranty time. Dealer should be able to fix that.

 

[Cummins12V98]

After having the CP4 swapped out and new pump installed I have noticed My power/fuel mileage is the same but one big difference is my exhaust brake does not work nearly as well as it did. I used to be able to use my exhaust brake going down hill with cruise on and it would put out LOTS of braking HP. It would usually keep me within 5-6mph of the set MPH on cruise. Now, it free wheels and yesterday cruise set at 60MPH the truck ran up to 77 mph..I had to turn cruise off to get it to slow me down. Tried both full and auto brake. No difference.

Are the e-brake parameters all the same or different for various GCVWR etc?

Are you using Tow Haul?

 

[Bug Out]

Are you using Tow Haul?

Yes. Always when the trailer is attached. It used to be very aggressive but not now. Makes me wonder if the "re-flash" maybe hard the wrong parameters in the E-brake settings..Mine is rated at 43K gross combined which I'm guessing is why it was as aggressive as it was..??

 

[AH64ID]

There isn’t a separate tune for various GCWR’s. There is a SO tune and HO tune, that’s it.

I can compare SO to HO for exhaust brake strength, but I recall them being the same.

 

[Bug Out]

I did notice on my way home from the camping trip going down hill, a main difference is its not downshifting either like it used to when slowing the truck down. Just a FYI..

 

[bcbender]

Not down shifting would seem to me that it is / was not in TH mode. Mine will downshift and keep slowing down almost to nothing if I lift and stay off the throttle and let it do its thing.

 

[Ozymandias]

Dealer time for sure.

 

[Bug Out]

Not down shifting would seem to me that it is / was not in TH mode. Mine will downshift and keep slowing down almost to nothing if I lift and stay off the throttle and let it do its thing.

Thats how mine was prior to the pump change. I always have it in TH with RV attached.

 

[Bug Out]

For poops and giggles I contacted RAM customer service. I was advised to contact a "Local dealer who will have highly trained personnel who can help with the issue". I will have to call the dealer and get in to the 3 week out line for appointments.

 

[bcbender]

Well in the three weeks, maybe try a ECM reset and see if a re-boot will take care of the gremlins

 

[Bug Out]

Well in the three weeks, maybe try a ECM reset and see if a re-boot will take care of the gremlins

And the reset consist of ? Disconnect batteries etc or ?

 

[bcbender]

That's what I was thinking, just disconnect and let sit for a while until the capacitance dissipates and the ECM is completely powered down, then re connect and try again.

 

[Bug Out]

Well, that was an utter complete waste of time.3 weeks ago I made the appointment... My exhaust break doesn’t work hardly anymore at or at all when it’s in cruise control (After injector [ump change) so I called the dealer up. Tell him I had the new injection pump changed, and that I’m hoping maybe they can re-flash the parameters or something in the exhaust brake, etc. So I get all the way to the dealership 7 o’clock in the morning, not to mention some piece of **** cut the front of the whole line in front of everybody, then he tells me its going to take a couple of days. Geez, wish i would have known that ahead of time.....I would have planned for it..Not to mention he says, "Oh, we have to go over somebody else's work etc etc so That could take time"......What exactly do you HAVE to go over??? The injection pump which is operating perfectly....smh.... I'll just leave cruise off going downhill for now..

 

[bcbender]

Well @Bug Out, seems like I may be in the same situation, Drove the truck to take my tractor in for a 200h service and EB seems not to be working correctly.. seems very slow to react (engage) and retarding pressure is about 1/3 what it used to be. In TH mode, it down shifts then is very slow to engage then drops out... basically did nothing to stop my GN trailer... Empty it performed about like it used to with 20k behind it... I wonder if the slider is sticking from sitting for a month or so with no driving? Anyway, curious if you ever figured out what was up with yours, I assume its not the CP4 swap because mine was done awhile ago, and this just cropped up today.. It's not right for sure, can you check the operation of the actuator with Alpha-OBD? I dont have time right now and its under warranty so probably best just to make an appt and have them do it.

 

[Turbo Terry]

I don’t think the exhaust brake sitting will ever stick .it’s when you don’t use it driving it soots uo and sticks

 

[Ozymandias]

I don’t think the exhaust brake sitting will ever stick .it’s when you don’t use it driving it soots uo and sticks

Only in the old ones and the ones thats didn't do the updates. The other cycle the VGT several times at every startup to break the residual soot and grime.

 

[Bug Out]

Well @Bug Out, seems like I may be in the same situation, Drove the truck to take my tractor in for a 200h service and EB seems not to be working correctly.. seems very slow to react (engage) and retarding pressure is about 1/3 what it used to be. In TH mode, it down shifts then is very slow to engage then drops out... basically did nothing to stop my GN trailer... Empty it performed about like it used to with 20k behind it... I wonder if the slider is sticking from sitting for a month or so with no driving? Anyway, curious if you ever figured out what was up with yours, I assume its not the CP4 swap because mine was done awhile ago, and this just cropped up today.. It's not right for sure, can you check the operation of the actuator with Alpha-OBD? I dont have time right now and its under warranty so probably best just to make an appt and have them do it.

I had planned to put it in the shop. Arrived and to my surprise they needed it for "2" days.....Going to call the selling dealer and see if they want to work on it in less then 2 days worth. I'll keep you posted. Mine does not engage when in cruise control. Won't downshift etc. It used to drop anchor like nobodies business in cruise when it went 2-3mph past the set speed. No more. I tested it and coasted from 60 to 77mph and no E brake activity to help slow it down. Cruise off, it slows right down...

 

[bcbender]

I don’t think the exhaust brake sitting will ever stick .it’s when you don’t use it driving it soots uo and sticks

Use it every time, that button is pushed before the gear selector is touched,

Won't downshift etc. It used to drop anchor like nobodies business in cruise when it went 2-3mph past the set speed. No more. I tested it and coasted from 60 to 77mph and no E brake activity to help slow it down. Cruise off, it slows right down...

Yeah,, mine downshifts just fine,.. but drops the EB , shifts down and there are several seconds before it "re-engages" and when it does its anemic at best... clearly a problem so I guess I'll call the dealer in the am and get it scheduled. . FWIW, the dealers cannot seem to get anything done same day anymore,... perhaps they are like the airlines overselling seats to make sure its always busy, my new Oddessy was in for a stuck seat latch and they kept it 3 days...