Hydramaster CDS issue

[JR Harvey]

OK spoke with Dennis via email and guys down here at Interlink. I'm new with the computer of these units. I previously ran pods for my RPM's and now I'm running it with the new computer.

With that being said I know the machine has cut offs set to kill the machine but my machine keeps just dropping from 1500 RPM's down to about 5000 RPM's at different times. Sometimes first start it does it. Sometimes in the middle of a big job it does it.

I know the machine has numerous safety shut offs but does anybody know which devises shut off the machine and which will drop the RPM's down but not kill it.

Example: The waste water tank has a kill sensor (turns machine off completely)

I'm looking for any other sensors that drop the RPM's and not kill it completely. I never had this issue with the PODs running the RPM's

Any ideas???

Thanks

 

[dgardner]

my machine keeps just dropping from 1500 RPM's down to about 5000 RPM's at different times.

I assume you mean 500 RPM, not 5000?

 

[dgardner]

One possibility in the CDS manual:

On GM gas engine vehicles, the PCM engine computer will cause the engine speed to
momentarily drop back to normal idle speed every time the air conditioner pump cycles on
or off. Make sure the operator of the CDS understands that the AC / HEAT switch needs
to be in the OFF position before activating the CDS unit.

The AC compressor cycles on in defrost mode too....

 

[Becker]

I'd bet money..

 

[Chris A]

I had a bad connection on the E-Brake sensor for the CDS, and it was doing the same thing. Fixed that and the problem stopped.

 

[Mark Saiger]

All the above mentioned places are also things I experienced. Dealership doing some work left the emergency brake wire loose. But also, it will occasionally happen to me on my Butlers because how they wired my stereo system with my GPS system the Kenwood has.

Every now and then, maybe twice a year my GPS seems to get a signal and it will knock my Butlers down to an idle.

Do you have a GPS that has been installed? Just a possibility.

 

[Shane T]

Have you checked the engine temp when it reduceds rpm? If the van engine is overheating its possible the ECM is switching to limp mode.

 

[JR Harvey]

Yes I meant 500 RPM.
The van is brand new. No check engine light on, no ac/heater on, emergency brake is on. The part that makes it tricky is it only happens here and there. That always makes it more difficult to pin point. Also no GPS or aftermarket stuff on van. I'm going to check the e brake sensor.

Thank you so very much everybody for your input. Helps a lot!!!

 

[sweendogg]

We have had the same issue over the years... 9/10 times its the trucks computer forcing back to idle most of the time because of lack of oxygen or heat build up. Remember that not matter how complicated the truck mount is. the vehicle engine has several more sensors and so if a sensor sends a bad issue it will throttle back. The truck is designed to be running down the road between 30 and 50 mph at the speed its running and the engine expects that amount of air flow, so if it doesn't and it hiccups electronically speaking its just going to send that signal onto the truckmount computer which will then bring your truck back to an idle. At that point you have to shut down truckmount and van engine and restart to reboot both computers. Id imagine a slide in wouldn't have this kind of issue as its not relying on two computers and a bunch more sensors.

 

[JR Harvey]

Hey Chris,
Do you know where the sensor for brake is located?
I cannot find it in my manual.

Thanks.

 

[Chris A]

Theres a little red wire coming out of the fuse panel under the drivers seat on mine, thats where the bad connection was. I'm not sure exactly where it runs to

 

[Chris A]

We have had the same issue over the years... 9/10 times its the trucks computer forcing back to idle most of the time because of lack of oxygen or heat build up. Remember that not matter how complicated the truck mount is. the vehicle engine has several more sensors and so if a sensor sends a bad issue it will throttle back. The truck is designed to be running down the road between 30 and 50 mph at the speed its running and the engine expects that amount of air flow, so if it doesn't and it hiccups electronically speaking its just going to send that signal onto the truckmount computer which will then bring your truck back to an idle. At that point you have to shut down truckmount and van engine and restart to reboot both computers. Id imagine a slide in wouldn't have this kind of issue as its not relying on two computers and a bunch more sensors.

That's interesting David because you're machine/van is about the same age as mine I think (09). Every once in a while it will shut down and I just restart the van, reset the brake and we're good. Only happens once in a great while...