6V92T, fast idle help

[Aussiecoach]

Hi All

Lonely Busnut here in Sydney Australia, wish there were more of us here. I've got a 40ft Denning Landseer with mechanical 6V92T and 6sp spicer.

I am searching for some help from the DD experts here.

I'm having trouble working out how the fast idle is meant to work, cause at present it don't. It has cable accelerator and stopper. I have found one air cylinder that activates when the high idle switch is on, which seems to be just to stop the accelarator from being used It is located next to the linkage at the front of the governor. I'm guessing there is another one to activate the fast idle bit, but am unsure if it is there or missing. On the side of the governer toward the back of it there is another hose connection (which I assume is air and hopefully the one I want to check, but I am too scared to play incase I bugger it up) Then at the back is a bolt or screw, which I assume is the idle buffer screw (maybe showing my incompetence here)
So would this other hose connection be for fast idle and if so what is in there and If I check there is air there, what would i do next to diagnos it?
Thanx in advance

Hopefully the pic worx and makes sense

[JackConrad]

I am pretty sure that second hose is the fast idle.  Follow that hose to the other end. If it is like our bes up here, it will connect to an electrically operated air solenoid.  Uusally the problem is in the elctrical part.  Do you have a wiring schematic?  If not, I would try to get one. When it comes to electrical problems, they are priceless.  Good luck.   Jack

[Dreamscape]

A lot of us do not use the fast idle, especially if the coach A/C has been removed. The main purpose was to keep up the rpm's when the coach is sitting keeping the passengers comfortable. The only help would be to air up the coach faster.

Maybe the PO removed it because he felt it wasn't needed and just another problem to troubleshoot if something goes wrong.

I tried to fix ours and decided that idling for long periods of time is wasting money on burnt fuel.

Jack is right on, get the schematic if you don't have one.

Paul

[luvrbus]

Looking at the photo of your engine the best I can tell you have a cruise control with the high idle built into it. Most of ours here have a holding cylinder on top like yours then on the left side of the governor where the buffer screw is replaced with a air cylinder (1 1/2 in in dia and about 4 inches long) with both cylinders tied together with one air line if the stop cylinder works on top so should the high idle.  
Love those Denning buses that is a real bus they could do battle with a tank and drive away



good luck

[Nellie Wilson]

Hi Aussie -

Wouldn't normally dream of contradicting Dreamscape, but you might want to check some converse opinions under the "To fast idle or not to fast idle..." thread.

Everyone I've talked to says using fast idle is important, and not just for running A/C. I'm guessing it was factory installed for a reason... but that's just me  .

I mean, these engines weren't built just for buses... and I'm sure many applications don't have A/C.

FWIW.

Nellie Wilson

[Dreamscape]

That's quite OK Nellie, I'm used to it!

[Nellie Wilson]

Dreamscape -

Big hugs!

Nellie

[fe2_o3]

My coach used a separate engine to run the A/C system. It has no fast idle...Cable