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I have a factory tach and factory ammeter both not working. All other gauges work.Engine has a 6al msd box and a 75 dura spark distributor. I tried msd but they are closed on weekend. Thanks Ron
 

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Did you purchase and install the MSD tach adaptor that is specifically for a current operated tach? MSD web sight has lots of info on the subject.

John
 

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subscribing, I have that tach adapter with 6al2 box and msd dizzy, I tried connecting it a couple of weeks ago without luck and have not tried since. THe factory tach is considered voltage so it would go to the white lead? also the ballast resistor has been removed so which leads (MSD to Ford) colors need to be connected?

thanks
 

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71stang99 said:
subscribing, I have that tach adapter with 6al2 box and msd dizzy, I tried connecting it a couple of weeks ago without luck and have not tried since. THe factory tach is considered voltage so it would go to the white lead? also the ballast resistor has been removed so which leads (MSD to Ford) colors need to be connected?

thanks

Factory tach is current trigger and gets connected to the tach adapter, not the 6AL box. Which tach adapter you need depends upon the type of ignition trigger you are using - white wire you need #8910, green/purple wires you need #8920. Follow the directions in the adapter installation manual and everything should work fine.

MSD 6AL-2 manual

MSD 8920 manual

MSD 8910 Manual
 

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http://img.photobucket.com/albums/v309/71stang99/IMG_1508.jpg

I finally was able to try this again and dug out a photo from last year before the motor was pulled and the ignition upgrade.

The two wires on the right of the resister are a key switch on +12 and once the ignition is on then the other wire reads +12v or so also. The wire on the left I ant to say went to the coil? Regardless the tach adapter instructions show that the white goes to the control box, black to ground and the other wire to a switched +12v wire. Is the resister still needed and if not would I just connect it two the key on +12v and the switched on +12 wires?

EDIT I just checked the wires again and I think the picture was a bit misleading, I want to say that the 'green' wire on the left was recrimped and coil wire would be the 'green' wire on the right with the red/white factory wire. So if I understand this in factory configuration the left side of the resistor would be the engine on +12v and on the right side of the resistor it would be the key on +12v and the factory coil wire for the tach?

Thanks.
 
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