Idle drops on Isuzu truck mount | TruckMount Forums #1 Carpet Cleaning Forums

Idle drops on Isuzu truck mount

Bojangles9717

New Member
Sep 19, 2012
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Taylor Amero
I have a 2006 Isuzu NPR box (diesel) with a White Magic Pro 1200HV. When the mount is engaged it will rev the truck up to about 1500-1800 RPM and all will appear ok but it will eventually drop the engine back down to a normal idle of about 700-800 RPM. The mount will remain engaged but the engine RPM will be at an idle and sometimes come back to operating speed for a few seconds, then it will go back to idle. Basically the PTO clutch on the engine is engaged and driving the truck mount, but the engine throttle is only at idle and not the 1500-1800 RPM needed.
 

BrianC

Active Member
Jul 23, 2011
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www.NewEnglandTruckmount.com
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Brian Collopy
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United States
This can be an issue with your throttle control or the vehicle itself. If there is a vacuum actuator style control, sometimes the inner bladder can be dried and worn out, or the adjustment nuts or cable a little sticky. For electronic controls, sometimes an ETM disparity will cause throttle fluctuation. A leak in your air system in the vehicle will also lend to throttle changes on a vacuum system. Normal idle should be in the 700RPM range or so, and the three speeds should be at 1000 (varies on Isuzus), 1300, and 1500RPM respectively. Based on the hardware installed, you may only get one speed (high idle of 1500 or so). 1800 is a little too high for these units.

If you need further help, have it checked out. It may end up being a vehicle issue. We have seen this before.

- Brian
 

Bojangles9717

New Member
Sep 19, 2012
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Taylor Amero
Hey, Brian
Oddly enough I just talked to you on the phone about this exact truck. There is no black box labeled "in power". I did however find a similar idle controller that is active only when the mount is activated. When the mount is inactive the built in idle advance on the truck itself works perfect, and is disabled when the mount is on leaving the other switch to control it. I'll call you tomorrow and see if you have any input with anything I may be missing.
It's Taylor from servicemaster by the way.
 

Dabigga

New Member
Jan 28, 2020
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Edmond
Hello everyone I have a Prochem Pto hydraulic. Just recently my rpms dropped and losing vacuum lift .also the thatcher gauge is up and down plus I noticed that the hydraulic hose on the governor box keeps jumping. If any one can help I’d appreciate it .thanks