I recently purchased a 1992 Genie Z-45/22 IC (2WD) Articulated Boom Lift (serial number 000626). It has a Ford dual fuel engine which I am running on propane. I've spent the past couple of months getting everything working properly and have found lots of useful information on this site. I'm hoping someone can point me in the right direction with my current issue. This machine is a "classic" so it has no computers, it is totally "old school" electronics.
The problem I'm having is that the motor will stall when I'm trying to use various hydraulic functions in "turtle" (low idle) mode. Things are fine if I keep the idle speed high (rabbit), but the manual implies that the hydraulic functions should work (and many do) in the low idle mode. For example. if I lift the main boom the engine does not (usually) stall, however lifting the secondary "Z" boom almost immediately stalls the engine. Operating the platform tilt adjustment will also stall the motor, but the platform rotate adjustment usually does not. (FYI - I just rebuilt the tilt slave cylinder so I now the hydraulic functions are working as they should.)
I've hooked up a tachometer to the engine and it shows me 1400 rpm at low idle (manual calls for 1200 rpm) and 2150 rpm at high idle (same as manual).
I suspect it has something to do with either adjustment to the hp limiter/engine governor setup, but I'm not 100% sure. When high idle is engaged the governor actuator throttles up the engine. However, when a load is placed on the hydraulic system in low idle mode (e.g., raise secondary boom) the engine's RPM drops off and the engine dies. The governor actuator does nothing to stop this. It seems to me that the governor would throttle up the engine to maintain the correct RPM under load, but the manual does not explicitly state this.
Can anyone tell me if my assumption is correct and that the governor is supposed to do more than just engage high idle speed? If so, what should I be looking at to diagnose this issue? If not, where else should I be looking?
FYI -- I've checked and adjusted the voltage on the hp limiter per the service manual. With the boom stowed and the foot pedal pressed in to activate high idle mode, I set the "A" potentiometer (max voltage stowed) to 8.0V (2WD spec). Then in low idle mode I set the "C" pot (reaction rate) to 0.01 to 0.03 V. Initially I found that the "A" pot was set a little low and the "C" pot was very high (read about 1.5V instead of 0.03V). I have not bothered with the "B" pot yet.
The reaction time on high idle engaging seems a little delayed (it's not like putting my foot on the gas in the truck) - also the delay seems pretty variable. With a meter hooked up to the 2 and 10 terminals, when I press the foot pedal, I see the voltage ramp up to about 10V and then bounce around 8V until it stabilizes. It does not ramp up in a consistent fashion from one time to the next. Sometimes the voltage will quickly rise, other times it seems to hang about at or close to zero and then lazily rises to 8V+. I've check the foot pedal and it's wiring appears to function properly (solid on/off circuit when pedal is depressed/released).
Sorry if I've written a novel here. I figured the more info the better.
Thanks in advance for any advice.
Regards,
Michael
The problem I'm having is that the motor will stall when I'm trying to use various hydraulic functions in "turtle" (low idle) mode. Things are fine if I keep the idle speed high (rabbit), but the manual implies that the hydraulic functions should work (and many do) in the low idle mode. For example. if I lift the main boom the engine does not (usually) stall, however lifting the secondary "Z" boom almost immediately stalls the engine. Operating the platform tilt adjustment will also stall the motor, but the platform rotate adjustment usually does not. (FYI - I just rebuilt the tilt slave cylinder so I now the hydraulic functions are working as they should.)
I've hooked up a tachometer to the engine and it shows me 1400 rpm at low idle (manual calls for 1200 rpm) and 2150 rpm at high idle (same as manual).
I suspect it has something to do with either adjustment to the hp limiter/engine governor setup, but I'm not 100% sure. When high idle is engaged the governor actuator throttles up the engine. However, when a load is placed on the hydraulic system in low idle mode (e.g., raise secondary boom) the engine's RPM drops off and the engine dies. The governor actuator does nothing to stop this. It seems to me that the governor would throttle up the engine to maintain the correct RPM under load, but the manual does not explicitly state this.
Can anyone tell me if my assumption is correct and that the governor is supposed to do more than just engage high idle speed? If so, what should I be looking at to diagnose this issue? If not, where else should I be looking?
FYI -- I've checked and adjusted the voltage on the hp limiter per the service manual. With the boom stowed and the foot pedal pressed in to activate high idle mode, I set the "A" potentiometer (max voltage stowed) to 8.0V (2WD spec). Then in low idle mode I set the "C" pot (reaction rate) to 0.01 to 0.03 V. Initially I found that the "A" pot was set a little low and the "C" pot was very high (read about 1.5V instead of 0.03V). I have not bothered with the "B" pot yet.
The reaction time on high idle engaging seems a little delayed (it's not like putting my foot on the gas in the truck) - also the delay seems pretty variable. With a meter hooked up to the 2 and 10 terminals, when I press the foot pedal, I see the voltage ramp up to about 10V and then bounce around 8V until it stabilizes. It does not ramp up in a consistent fashion from one time to the next. Sometimes the voltage will quickly rise, other times it seems to hang about at or close to zero and then lazily rises to 8V+. I've check the foot pedal and it's wiring appears to function properly (solid on/off circuit when pedal is depressed/released).
Sorry if I've written a novel here. I figured the more info the better.
Thanks in advance for any advice.
Regards,
Michael
Genie 1992 Z-45/22 Stalls on Hydraulic Functions
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