Stepper Motor Test

How long does the motor cycle for? With key off, the motor is pulsed with 6 volts to reset then b+ to verify movement. Should only be a few seconds

I will give them a shout out.

Thanks

mikecanz, Thanks for responding Mike. The stepper motor will cycle either until I loosen up the negative battery cable or when the battery dies. I am going to install a pair of Radio Control micro switch’s in line of the two hot leads into the stepper motor itself to cut the circuit. I would really like to know the reason why this thing is doing what it is doing.
Thank you for your response.
Doug

So, If I'm reading this correctly. Yours never stops moving? and no service light? Pin D should retract will 6 volts for about 5 seconds as the clock turns the DIP chip off. Is there a possibility that one of the pins is shorted to power? ground is always supplied thru the ECU in this setup. Pin A-D are together PIN B-C are together.

Does the motor cycle with the key in the on position and the engine off?
Can you pop the connector off and to a circuit test from the PINs to power(b+)?

Correct it never shuts down.
I traced the wires all seem to be good. I thought possibly a bad ground so I added grounds. Found no chaffed wires or any wire that looks to be touching at the pins or elsewhere.
My first ecu had a number 28 pin loose with corrosion around several pins so i purchased another ecu from Australia for the same/similar VIN. Keeping in mind the stepper cycled even with the OEM ecu.
If I fire up the engine & of course the stepper cycles, & when I shut down it continues. Just to turn the ignition on, engine off, the stepper does cycle but only after 15-30 seconds with ignition on engine cold & off.
This thing is a real nightmare.
I have zero trust in Magneti Merelli components along with DigiTek dash’s. I really appreciate all the input you are giving me.

Correct it never shuts down.
I traced the wires all seem to be good. I thought possibly a bad ground so I added grounds. Found no chaffed wires or any wire that looks to be touching at the pins or elsewhere.
My first ecu had a number 28 pin loose with corrosion around several pins so i purchased another ecu from Australia for the same/similar VIN. Keeping in mind the stepper cycled even with the OEM ecu.
If I fire up the engine & of course the stepper cycles, & when I shut down it continues. Just to turn the ignition on, engine off, the stepper does cycle but only after 15-30 seconds with ignition on engine cold & off.
This thing is a real nightmare.
I have zero trust in Magneti Merelli components along with DigiTek dash’s. I really appreciate all the input you are giving me.

Odd - have you checked resistance values between A and D / B and C? when you hear the motor moving is rpm at idle effectively hunting? the ground circuit for the motor totally depends on the ground circuit for the ECM. I'm going through a similar nightmare right now with mine, the only difference is my ECM seems to not know how to control it. If you have the tank off I can provide you with a video from Piaggio group on how to test the GRiSO stepper motor.
It certainly sounds like it has a short to power somewhere along the harness unless you have two bad ecu's which is entirely possible

Mike,
I haven’t checked out the resistance yet. I’ll have to put another ground strap on the ecu to the battery -. My tank is off & will remain off until I figure out bothering the Stepper & side stand idiot light.
Are there anything’s that are added to the ecu or the rest of the electrical system that is on the bike for proper amperage, voltage? I had added LED rezoma indicators. Nothing started to come about until it sat for sometime. Could there be a resistor switch that might be stuck?

Okay guys & gals. If you have a stepper motor that runs on after shutting the ignition off or just having the issue of the stepper revving the engine at idle & you wish to disconnect it. On my electrical nightmare 06 GRiSO I am using single K&N air filters on each throttle body. I rerouted the stepper motor vacuum lines back into the SM side vacuum nipples. It’s an endless loup, the upper nipple I just sealed with a silicon cap to plug it. The breather that comes from the puke tank up front just in front of the alternator, this vacuum line lI used a T. The — part of the T has vacuum lines going into the throttle bodies inside nipples. The | part of the T is the line that comes in from the puke tank. Keep the stepper motor plugged in.
As for the ST cycling as mine does thousands of miles after the re-piping. This is how I prevented it from cycling with the bike shut down. Find the two hot leads to the SM, colors pink the other yellow. Snip these wires in half. Buy two RC micro switch’s. In a parallel function, using extra length wire, run the red wire to the pink lead going to the motor of the pig tail the other end goes to the incoming wire from the ECU. Solder them with the perspective wires. Do the same with the yellow wire. Mount the switch’s where you wish, I mounted them to the main down tube on the left side of bike with the red wire to the back of the bike. This way you know this is On position to tell the ECU that all is well. NOTE: you will receive a “SERVICE” with the RED Triangle on for a second or two & then they go off tell the ECU all is well. Done riding move the switch nuns to the black, this shuts the SM down. You can either leave it off until you ride again or you can wait to see how long it takes for the SM to stop cycling. You are able to hear the SM cycle for several seconds & if your’s shuts down when in factory installed, your SM should shut down in a second or less. Mine never shuts down until I switch it OFF. PIAGGIO/Guzzi really should recall all the bikes that rev’s the engine at idle or shuts off as mine does.
If your interested in saving aggravation & for the cost of a little bit of wire, solder, shrink tubing & two micro RC switch’s you should never have an engine that rev’s automatically at idle or may never have the SM cycle on.
Questions or comments feel free to ask or send.