Does your exhaust break whistle?

boostin

Adventurer
I recently learned my vacuum chamber was not holding any vacuum so I purchased a new vacuum chamber.

Once installing it I noticed any time the exhaust brake was applied there is a whistle that was not there before.

Does your exhaust break whistle when applied?
 

SkiFreak

Crazy Person
Does your exhaust break whistle when applied?

I do not notice a whistle when driving, but when the engine is cold and I engage the engine load switch (which engages the exhaust brake) I definitely have a whistle in the exhaust.
 

boostin

Adventurer
I do not notice a whistle when driving, but when the engine is cold and I engage the engine load switch (which engages the exhaust brake) I definitely have a whistle in the exhaust.

Yes my exhaust brake deff whistle when I aplly that switch as well.
 

david506th

Adventurer
Heck, I cant even seem to get my exhaust brake to work no matter how I fiddle with the knob. Deceleration in manual or auto does the same and am finding I have to use the brakes like a regular vehicle when slowing. The Fuso techs (about as highly recommended as a redneck with a sledgehammer it seems locally) tells me everything is golden though.
 

kerry

Expedition Leader
I haven't heard mine whistle. There's a knob which activates the brake when cold but the right stalk also turns it on and off. David, have you tried that?
 

david506th

Adventurer
I haven't heard mine whistle. There's a knob which activates the brake when cold but the right stalk also turns it on and off. David, have you tried that?

Your referring to the knob to the lower right of the steering wheel correct? If so I have push/pulled it from Auto to Manual and rotated which is supposed too (if I read the manual right) activate your exhaust brake controls.
 

kerry

Expedition Leader
On mine that knob controls whether it comes on at idle when cold. The stalk coming out of the right side of the steering column (wiper control stalk) controls whether it activates when driving or not. Can't remember which way it moves (up/down or in/out) but I do know that I inadvertently turned it off one time before I knew the stalk controlled it and I thought it had broken. Someone on here relieved me of my ignorance. This is on a 1999 model.
 

mog

Kodiak Buckaroo
The rocker switch just controls the exhaust brake to get the engine to warm up faster by closing the exhaust brake to hold more heat (restricted exhaust).
FYI the 'turnable' knob controls the engine idle speed for faster warm up.
The stalk turns it from 'auto' (closes the exhaust brake during deceleration) to 'off' (does not activate).
You should get a yellow annunciator light when it is working (closed during deceleration). AND you should certainly be able to feel it working. A nice downhill, no wheel brake application, turn it from off to auto, you will feel a major deceleration from the exhaust brake operating (closing). The Fuso exhaust brake works great and is very quiet (no loud semi-truck Jake Brake sound)
2002--YMMV

Exhaust Brake switch
f-eb.jpg


Warm-up
f-wu.jpg


Idle Speed
f-id.jpg
 
Last edited:

SkiFreak

Crazy Person
I should add... I cannot remember there being a whistle with the OEM exhaust brake, but with the 3" one I installed there definitely is.
I am assuming that the whistle is made by the exhaust rushing past the edges of the butterfly when it is closed. You can adjust the gap between the butterfly and the exhaust brake body, which might negate the noise, but I saw no reason to do this as the gap on mine is set to the specification given in the manual.
 

david506th

Adventurer
The rocker switch just controls the exhaust brake to get the engine to warm up faster by closing the exhaust brake to hold more heat (restricted exhaust).
FYI the 'turnable' knob controls the engine idle speed for faster warm up.
You should get a yellow annunciator light when it is working (closed during deceleration). AND you should certainly be able to feel it working. A nice downhill, no wheel brake application, turn it from off to auto, you will feel a major deceleration from the exhaust brake operating (closing).

I get the yellow light come on when the accelerator is not being pushed and when any brake it applied I get a "low vacume" orange light come on. I was told by the Fuso service tech that this is normal. All that being standard, I feel or seem to feel no distinct exhaust brake being applied. It coast just as a car would and has no resistance applied. I have driven vehicles with exhaust brakes so I know the feeling.
 

kerry

Expedition Leader
What year is your truck? I never see a low vacuum light. Sounds to me as if the tech is wrong. You could test it by applying vacuum with a Mity Vac using a long hose while driving to see if you can manually activate the brake. Resistance is noticeable on my truck when the brake activates.
 

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