Cruise control and Engine Brake

[Arizona Lizards]

Originally Posted by Dutch Star Don

When I had mine changed, they told me there was no such thing. Luckily, I had an email from Cummins on how to make the change. The tech read the email and said he never knew it cold be done. Unfortunately, he kept the email.

I’ll email Cummins so I can show my tech next time. Thanks Don.

[Mark D]

I have an American Coach but a Cummins is a Cummins. I have an ISX and it's programmable, at 3 over cruise speed the first stage will come on at 5 over the third stage will come on. This is only if the engine brake is on. This can be programmed by the dealer.

[Spk64]

Originally Posted by Dutch Star Don

When you start to descend a grade with the cruise control on, the system is designed to allow about a 6-7 mph increase in speed, before the engine brake engages. This is programmable. I had mine changed to engage within 2-3 mph over the set speed. It works much better now. It was a $110.00 to have it changed via the Incite program that Cummins uses.

Don
When your descending a hill do you first see the trans downshift then later the engine brake kick in?

I am wondering if what I am seeing is that the trans downshifts to 3rd (actual only drops to 5th initially at highway speeds) first then possibly at a much higher over speed the engine brake may kick in when using cruise control.

Mine seems to down shift to 3rd (actually only goes to 5th initially at highway speeds) at around 3-5 miles over the set point. I never did wait too much longer to see if the engine brake actually engaged , as soon as cancel was pressed the engine brake would kick in and actually slow me down.

Without cruise engaged letting off accelerator trans down shifts and engine brake engage both happen at the same time.

[Craig36]

I may be wrong, but it seems like a conflict keeping cruise on and the engine brake at the same time. Certainly not going up and down hills.

I turn off the cruise when doing big hills, mainly because cars and trucks keep pulling in front of me requiring me to slow down a little.

[Algoma]

Originally Posted by Craig36

I may be wrong, but it seems like a conflict keeping cruise on and the engine brake at the same time. Certainly not going up and down hills.

I turn off the cruise when doing big hills, mainly because cars and trucks keep pulling in front of me requiring me to slow down a little.

I'm with you. I hit the brake (which disables cruise) until my speed drops enough so I can drop into 4. I will then use then use the engine brake to hold my speed. I just don't understand why anyone would have cruise control and engine brake on at the same time.

[Charlie and Martha]

I find that the cruise control on my Northern Star is very hard to disengage by hitting the brake. Is there any adjustment that can rectify that? I usually just click off the cruise but sometimes you get caught by surprise.

As for the engine braking, mine is totally annoying yet essential. If I let up on the fuel pedal even slightly the thing is trying to engage.

[BBelanger]

Originally Posted by Algoma

I'm with you. I hit the brake (which disables cruise) until my speed drops enough so I can drop into 4. I will then use then use the engine brake to hold my speed. I just don't understand why anyone would have cruise control and engine brake on at the same time.

I use my cruise control and always have the engine brake on. Set the cruise to 65 and going down a hill it accelerates to 72 then the brake kicks in. Perfect for me.

[palehorse89]

Originally Posted by Charlie and Martha

I find that the cruise control on my Northern Star is very hard to disengage by hitting the brake. Is there any adjustment that can rectify that? I usually just click off the cruise but sometimes you get caught by surprise.

As for the engine braking, mine is totally annoying yet essential. If I let up on the fuel pedal even slightly the thing is trying to engage.

Year's back, I also was frustrated with the Allison setup.......
I had both the ECM & TCM reprogramed,
Engine brake activates on closed throttle position, droop set to 2 mph over and under speed, transmission set to stay in 6th gear, no downshift! if more braking on hills, I just interact with the shift pad and hit the down arrow ........just as most do climbing hill's..........My cruise control works very well with this set up..........
Allison still downshifts on it own when slowing per the speed set points right down to 5 mph.
There are a lot of parameters in those module's that can be programed to suit ones driving needs and wishes.........when bought, you just have the factory default setting's, which is a starting point for manufacure's........most own/drive/sell without knowing that there is a lot of adjust ability to the ECM & TCM module's to make their driving a lot more enjoyable.........

[Spk64]

Originally Posted by BBelanger

I use my cruise control and always have the engine brake on. Set the cruise to 65 and going down a hill it accelerates to 72 then the brake kicks in. Perfect for me.

Traveling through the hills of West Virginia and using the engine brake with cruise was nice. Seems like you are either going up a hill or down a hill and most times through a curve. I may have not waited long enough for the engine brake to kick in. At about 72 is when I would cancel the cruise which was set at 64-65 but the trans had already downshifted sooner. I have made the same trip 3 other times without the engine brake working and it took more work downshifting and on the service brakes more than I liked. I am ready for a redo on the mountain passes we went down this past spring without the engine brake working.
I may call the Cummins shop and see what they will charge to change the settings.

[BBelanger]

Without the cruise control on going down a hill, the engine brake wants to kick in all the time almost as soon as I get off the accelerator. The cruise control allows the coast. Works great.

[Dutch Star Don]

I don't see how people can have an issue using cruise control down a hill. Have you ever driven the Baker grade coming out of Vegas.....it's more than 15 miles long. Why wouldn't I want my cruise control handling my deceleration. For those not using the cruise, you're spending the entire downgrade speeding up and slowing down by manipulating the brakes and throttle. Can be very tiresome and can both confusing and aggravating to traffic behind you.

One of the biggest reasons I bought a coach with an engine brake was so that I didn't have to work so hard going downhill. Maybe some of you don't see many grades, but out west, every where you go, has at least one or two long 6% grades.

"Spk64"......My engine brake comes on first, as evidenced by the icon on the dash. If it doesn't hold, the coach will start downshifting. After four years of driving this coach, especially if I know the grade well, I just downshift to 5th and enjoy the scenery.

[BBelanger]

It’s an automatic transmission and automatic cruise control and automatic engine brake. I like to use them to lessen my work load. Disabling them or reprogramming them differently than the factory design seems counterintuitive.

[Spk64]

I agree with you guys on the use of cruise on hills. As I mentioned this was my 4th trip down same stretch of road and with the cruise and engine brake it was a much easier drive the last trip.

Don I need to try and determine if the engine brake portion is kicking in at same time transmission kicks down. I do not have a light on the dash just looking at shifter console if it is in 3rd my engine brake is usually active under non-cruise driving. With cruise I am wondering if the engine side is kicking in later or at all. In some reading I have read where the engine side may be disabled with cruise on. Which I do not think to be the case, only the bigger hills seemed to be an issue.