Hello guys... I have the Merc computer and would like to pull hours off of a few 500EFI's but have no idea how to power the computers? I know that they do not have to be running... they just need to be powered up... just like turning on the key and not starting. Does anyone know how to get this done?

Any help is appreciated!!! Thank you

Q

hook up a jump pack to starter positive and ground to block and locate purple wire in main harness and run extra positive to it acting as ignition switch

Sounds great and thank you!!.. Also, is there any way to tell which pin the purple wire is behind? I didnt know if there was a standard position for the purple wire... at this point, the harness is wrapped and i cannot see anything behind the plug. Or, is there another place within the harness that I can find the purple wire?

Thank you!!

If you have a DVM digital volt meter do the following.

switch it to continuity testing... touch the two leads together, your DVM should beep, squawk, light up, or the digital read out should go to 1.000.

Now find the purple wire on the alternator... apply one of the leads from the DVM and keep it there.
Take the other lead and probe the 10 pin connector until you get the same results as in your test above.
Now mark it.... This is your ignition

Next find the 2 larger pins in the 10 pin connector, one is for ground (black) and the other is red (positive). One goes straight to the 12 V terminal on the starter. Probe the starter 12V post and one of the larger pins in the 10 pin connector. Your DVM should respond the same as in the previous find. Mark it

Now attach the battery as described in the previous post.
Now apply a jumper between the identified pins on the 10 pin.

You have now effectively turned on the ignition system resulting in ECU activation.

Note this will also cycle the fuel pump. Use caution

You can take it to a service facility, power up the harness and plug the ECM into a reader which will give you all the info.

you can also send the ECU to me and I can tell you every thing you wanted to know and then some. I don't need your harness.