For those of you that are required to do a smog test on a dyno, I had a new one come up today. The testing agency by our shop has a single axle dyno and we were sent away today since they said that if they perform a test it will cause issues with the ABS brake system and traction control functions of the truck.

They sent us to a location that has a dual axle dyno for the test (front and rear axle). It is a 40 minute one way drive, I understand if the vehicle was All Wheel Drive all the time, but it isn't.

This single axle dyno has done my Smog tests on my 2008 F250 4x4 and on my 2013 F250 4x4, so several years of testing.

Either they have a new tech in charge that doesn't know what he is talking about, or there has been issues I am not aware of.

Have you guys had any similar experiences?

 

I have no answer for you but I have an idea.

Seems to me that if the smog test requires wheel speeds over 25mph the computer in the truck would go haywire trying to understand what the heck is going on. I'd bet if my truck were strapped to a dyno and the front wheels were stationary the system would not allow any power to go to the rear wheels. Looks like wheel slippage.

Surely there is a protocol to turn off all that traction control stability stuff for testing/diagnosis situations though.

 

I've not had a problem. Roll on the dyno, chain up and run through the test.
Never had my front end on anything other than the concrete shop floor.

 

That front end is completely disconnected on any super duty in 4x2 and if you hold down the TCS button for 10 seconds, it disables a good portion of that system. I don't see how you would have an issue. I think you're on to something with the new tech.

I haven't ever had to put mine on a dyno but I don't see how it's any different than being stuck in mud. I have been stuck, turned off the TCS by holding the button and the TCS light no longer blinks so I can spin that tire all I want (until I switch to 4x4 of course). Leaving TCS on when attempting to spin one wheel does create confusion with auto braking and deceleration occuring.