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Air Throttle

Yahoo Message Number: 100342
I have a 1995 Magna with the Cummins  8.3C  engine.  The problem is that it will not return to idle  when the ambient temperature is 40 degrees or less.  The throttle works independently of the cruise control.  This is not a minor problem.  If the RPM's are too high I am unable to shift out of neutral and when cruising the exhaust brake will not activate unless the RPM's drop back to near idle.  When the weather is warm the throttle works as it should. I have tripled the return springs and checked the air line for water.  Cummins has been unable to help and neither has Gillig.  I realize that most CC owners have newer coaches with the electronic throttles; however, there are a lot of the older coaches like mine that are still rolling.  Have any of you experienced problems of this nature or have any suggestions as to a cure.

Ken Hurst.

Re: Air Throttle

Reply #1 –
Yahoo Message Number: 100343
- [quote author=[Country\-Coach\-Owners]" Country\-Coach\-Owners@yahoogroups\.com\>] > I have a 1995 Magna with the Cummins  8.3C  engine.  The problem is that it will not return to idle  when the ambient temperature is 40 degrees or less.  The throttle works independently of the cruise control.  This is not a minor problem.  If the RPM's are too high I am unable to shift out of neutral and when cruising the exhaust brake will not activate unless the RPM's drop back to near idle.  When the weather is warm the throttle works as it should. I have tripled the return springs and checked the air line for water.  Cummins has been unable to help and neither has Gillig.  I realize that most CC owners have newer coaches with the electronic throttles; however, there are a lot of the older coaches like mine that are still rolling.  Have any of you experienced problems of this nature or have any suggestions as to a cure.

Ken Hurst.[/quote]

Ken,I may be able to give you some suggestions. My coach is a 99 with electronic throttle.I am not sure how your throttle is set up. But I have a lot of experience on oilfield trucks and equipment with air. The first thing to check is the foot actuator to make sure it is not leaking air. To check this unhook the line at the fuel pump, at idle there should be no air coming out of this line. Even a small leak will not let it return to idle.
You may have a quick release valve at the cylinder. This lets the air exhaust at the cylinder for a fast return to idle.
Hope this helps Doyle Chandler
 

Re: Air Throttle

Reply #2 –
Yahoo Message Number: 100350
Doyle,

Thanks for the information.  I have a new cylinder on order for the foot actuator.  When it arrives I will check out what you have told me.

Ken Hurst