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Old 08-19-2014, 12:47 AM   #6841 (permalink)
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Originally Posted by Astro View Post
My first guess would be a low supply voltage.
Is the supply voltage still around 5v when it is in the truck?
Maybe try using an independent supply voltage to test it when it is bolted in position.

Or try taking it off the firewall but still connected to vehicle supply to see if the mounting position is the cause.

The cable allows the throttle arm to move all the way to the physical stop?

Could the wiring changes to the controller still have a series resistor in the supply circuit or something like that that allows the supply to test as 5v unconnected but when connected to the pot box it doesn't deliver full 5v?
Okay did some experimenting

Being mounted to the firewall has nothing to do with it. bad guess

The 5V supply from the controller is fine it remains at 4.94V.

Drum roll ......

The controller is loading the signal line. If you disconnect the signal line from the controller the signal line rises to 4.8v at max throttle. Connect to the controller it can only rise to 3.85v.

I think they can only supply 2ma of current on the output, but the pull down resistor is sucking 1mA. Maybe the pulldown should be more like 47k instead of 4.7k.
yep, but I'm not sure it is a problem I need to fix as it all works fine with the program variables set for the voltage drop.

Last edited by jedsmd; 08-19-2014 at 01:20 AM..
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