Hotwire Stepper Motor

landrovernuts · Post by **landrovernuts** » Mon Apr 01, 2013 8:54 pm

Hi
I am after some help! I have a handfull of stepper motors for a 3.9 efi, some of which I know are genuine parts and some are ebay specials, but cannot tell which. Does anyone know the connections on the stepper motor so I can manually run them in and out with an external power source so as to see if they are knackered/seized or if they do move so as to partially dismantle them to clean and lubricate them? I know you can do it by removing from the engine and starting and stopping etc, however the shed is slightly more enticing during this weather and possibly much safer!!

Toby

richardpope50 · Post by **richardpope50** » Tue Apr 02, 2013 9:13 am

I've just sorted mine out for connecting to MegaSquirt.

Viewing into the socket of the stepper motor top left is coil 1a top right is coil 1b, bottom left 2a and bottom right 2b. Connect across 1a and 1b, and 2a > 2b. Somewhere on the web it says you cannot harm things if you get it wrong. There are also some more instructions under 'cleaning hotwire stepper motors' if you look hard.

I found that if you cycle on / off a few times the cone + shaft came off so you can clean. I also put some 3 in 1 oil into motor down the shaft hole.

To re-assemble, gently screw shaft in until plastic key and keyway touch. Then hold shaft (so it does not come out / off) and cycle on / off several times and the cone gets closer to stepper body ending with cone right into to stepper body.

Note my cycle was switching MS on then off and MS simply gives a pulse to set the stepper. It's about a second or two so I did not actually cycle manually direct from the battery.

landrovernuts · Post by **landrovernuts** » Thu Apr 04, 2013 5:53 pm

Thanks Richard - I will give it a try hopefully on the weekend.

Toby