Cruise Control Vs Exhaust Brake

[1ciderdog]

Joe T
Would I correct in my assumption that the ECM can only be programmed by the Cat service shop?

[Gary RVRoamer]

Hmm. My Freightliner/Cummins has a mode that doesn't fit any that JoeT described. Those modes sound like Caterpiller terms too.

I have an engine brake (Cummins ISL) and unless the Ebrake enable switch is OFF, the engine brake engages whenever the accelerator pedal goes to zero (no fuel flow). It stays on until the pedal is pressed again. If the Cruise is on, the engine brake is automatically disabled. I haven't noticed if the cruise will disable itself if the speed goes too high and I've let it run 10+ mph over at times.

[wayno55304]

Originally Posted by OneRVer

My cruise Control will shut off when ever my exhaust brake engages. When my exhaust brake engages my brake lights come on so I figure that triggers the cruise control and turns it off.

Soooo, when ever I am going down a small grade and the fuel peddle backs off just a little the exhaust brake engages and I have to reset the cruise.

Is this common or is there something else I can do to prevent this? Other then turning off the exhaust brake.

Google brake switch, after You install the switch , you drive with exhaust brake on, it will go coast when you're off the throttle on cruise, but will engage only when you tap the brake. Nothing to reset.

[OneRVer]

Originally Posted by JoeT

The ECM Can be programmed in one of three modes:

Coast Mode - engages the exhaust brake when the brake pedal is pressed and disengages when the pedal is released.

Latch Mode - engages the exhaust brake when the brake pedal is pressed. The exhaust brake will remain engaged when the brake pedal is released until the throttle is pressed or the engine RPM drops below 800 RPM or until the exhaust brake is turned off.

Manual Mode - exhaust brake will activate anytime the exhaust brake switch is on and RPM is above 800 RPM and the engine is not being fueled.

Coast and Latch are available when the Cruise Control Switch is "on". Manual mode does not require the Cruise Control Switch to be "on".

Thank you Joe for this list.

Out of your four I only have the one, Manual Mode. I have sent an email to the local Cat with my engine serial number asking him for more info on that mode.

Will let you know what he says.

[OneRVer]

Originally Posted by wayno55304

Google brake switch, after You install the switch , you drive with exhaust brake on, it will go coast when you're off the throttle on cruise, but will engage only when you tap the brake. Nothing to reset.

Wayno thank you. This is something I might have to try. Do you have one of these, if so, did you have to get inside the steering column to wire this device up?

[CD]

You guys and all your complicated settings. My EB is very simple. When it is turned on, it is on when peddle is up and off when peddle is depressed any. Now if the CC is also on and the peddle is up, EB tries to slow us down & CC tries to speed us up and we have LOTS of black smoke. I seldom use the CC and use the EB most of the time. With 80k+ on the odometer I have over 60% brake pads yet.

[AFChap]

I sometimes use my exhaust brake with cruise control on with my '03 Winnebago (Spartan chassis w/Cummins ISC). In rolling terrain with lower than hiway cruise speed limits it keeps me from gaining too much speed when coasting down the small hills. I have also used it for the same purpose for the bridge/tunnels in the Hampton Roads VA area. I can't tell you how it is set up so that they work together, but they do. And when cruise is engaged and the EB kicks in the brake lights do not come on unless/until cruise is dis-engaged by a tap on the brakes or gaining too much speed or a manual downshift to 3rd. Maybe that is part of the secret ...my Allison tranny is set to drop to 4th when the EB engages. Some are set to drop to 2nd. A drop to 2nd definitely would dis-engage cruise on my coach.

[wayno55304]

Originally Posted by OneRVer

Wayno thank you. This is something I might have to try. Do you have one of these, if so, did you have to get inside the steering column to wire this device up?

I have one I took out of previous coach. Will install in new M/H at friend's house in week or so. I mounted mine in the same exhaust brake switch from factory,perfect fit. On new M/H will mount to factory brake switch also. Homer at Brake Switch gives a discount to FMCA members and will help with install questions. If you search web there are some sites with how to pictures.

[JoeT]

Originally Posted by 1ciderdog

Joe T
Would I correct in my assumption that the ECM can only be programmed by the Cat service shop?

Yes, ECM programming will have to be done by Caterpillar.
If you decide to have it done, let me know, I can recommend a couple of other changes that I think you would like.
If you are a member of the FCOC yahoo group you can go to the files section and find a pdf file I uploaded called "programming CAT". It shows all of the programming.

[OneRVer]

JoeT, when I was at Cat having my cooling system flushed out, I had the tech do a print out of my parameters. I was there on a Saturday and the tech was not sure how to make any changes and did not want to bother the shop manager on his day off. I was charge for half hour of labor and $45.00. Oh well, at least I know what my parameters.

Wayno, thank you. You have been most helpful.

[OneRVer]

Originally Posted by JoeT

The ECM Can be programmed in one of three modes:

Coast Mode - engages the exhaust brake when the brake pedal is pressed and disengages when the pedal is released.

Latch Mode - engages the exhaust brake when the brake pedal is pressed. The exhaust brake will remain engaged when the brake pedal is released until the throttle is pressed or the engine RPM drops below 800 RPM or until the exhaust brake is turned off.

Manual Mode - exhaust brake will activate anytime the exhaust brake switch is on and RPM is above 800 RPM and the engine is not being fueled.

Coast and Latch are available when the Cruise Control Switch is "on". Manual mode does not require the Cruise Control Switch to be "on".

Ok Joe this is my reply from CAT.

If we set the Exhaust Brake Mode to Latch, when the cruise control switch is on you would have to apply the service brake to get the exhaust brake to come on.


The only thing is, per my print out I only have a Manual Mode. Maybe the Latch Mode is a file inside the "Exhaust Brake Mode". I guess I will have to pay another $45.00 to find out.

[cbeierl]

Originally Posted by OneRVer

Ok Joe this is my reply from CAT.

If we set the Exhaust Brake Mode to Latch, when the cruise control switch is on you would have to apply the service brake to get the exhaust brake to come on.


The only thing is, per my print out I only have a Manual Mode. Maybe the Latch Mode is a file inside the "Exhaust Brake Mode". I guess I will have to pay another $45.00 to find out.

'Manual' is the current setting for your 'Exhaust Brake Mode' parameter--that parameter should be able to be set for 'Manual', 'Latch', or 'Coast' mode.

There may also be an 'Auto Retarder in Cruise' parameter (from the CAT programming parameters booklet):

Description:
Auto Retarder in Cruise determines the miles per hour (km/h) value above the cruise set speed that the engine retarder will turn On. The Retarder switch must be in the On position and cruise control set, for this feature to operate. Programming the Auto Retarder in Cruise parameter to 0 (zero) will disable the feature. This parameter works in conjunction with the Auto
Retarder in Cruise Increment parameter. The initial braking level (Low or Hi) of retarding is dependent on the value of the Auto Retarder in Cruise Increment parameter.

Example: The cruise speed is set at 55 MPH and Auto Retarder in Cruise parameter is programmed to 3 MPH. When the truck accelerates to 58 MPH, by going down hill, the retarder will activate.

Available:
All electronically programmed on-highway engines

I have mine set to 'Soft Cruise' (allows the speed to vary slightly above and below the set point), the Exhaust Brake is set to 'Manual' mode and 'Auto Retarder in Cruise' set to 5. When Cruise Control is on and the Exhaust Brake is also enabled I see the following behavior: When/if the vehicle speed reaches 5 mph over the set speed the Exhaust Brake comes on WITHOUT a transmission downshift. If the speed continues to increase to about 8 mph over the set speed the transmission will then be commanded to downshift (to 2nd in my case) as well. When the vehicle speed drops back down to less than 5 mph over the set speed the Exhaust Brake will be de-activated, but Cruise Control will still be active.

[OneRVer]

I have mine set to 'Soft Cruise' (allows the speed to vary slightly above and below the set point), the Exhaust Brake is set to 'Manual' mode and 'Auto Retarder in Cruise' set to 5. When Cruise Control is on and the Exhaust Brake is also enabled I see the following behavior: When/if the vehicle speed reaches 5 mph over the set speed the Exhaust Brake comes on WITHOUT a transmission downshift. If the speed continues to increase to about 8 mph over the set speed the transmission will then be commanded to downshift (to 2nd in my case) as well. When the vehicle speed drops back down to less than 5 mph over the set speed the Exhaust Brake will be de-activated, but Cruise Control will still be active.[/QUOTE]

The people at the local Cat shop could not explain how Soft Cruise worked. I thank you for doing it for them.

[cbeierl]

Here's a link to the Cat document on programming Cat Electronic Truck Engines: Programming CAT.pdf (You will probably need to join the Freightliner Chassis Owners Club Yahoo group to access the doc.) This has all of the info on programming the Cat ECM.