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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: Gagecampbell82 on November 14, 2015, 03:07:51 am
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I have what is believed to be a msd 6al box, the stickers are worn off but based on the #s that's what it is. I'm running a Mallory distributor ( i don't know to much about it I'll try to get the part#) and a sunpro super tach 3 tachometer.
Based on msd's books I'm supposed to wire the tachs hot and ground as usual as well as the power for the light. Then hook the green tach signal wire to the correct place on the msd box, (there's only this plug and a 2 wire connector for I believe a magnetic crank trigger if I remember correctly)
We had a super tach 2 that supposedly worked in the truck before, then I went to hook it up after we got the engine in it and it didn't work. We tried everything including hooking the tach signal to the negative side of the coil like the manual said may be needed in certain setups. So I went to buy a new one And the super tach 3 was on sale $2 cheaper than the regular price of the super tach 2. So I said why not a 5" tach with a shift light lol.
But we have tried everything we know to do with both tachs. Once I got it to work but the needle was spinning in reverse as if 10k rpms was 1k. Msd makes two "signal filters" or "tach adapters" but I'm not sure which I need. I've followed the msd wiring instructions and I have it all right.
Has anyone ran into this problem before? I would love to know my rpms, but mostly to make the huge tach on the dash actually do something.
This is the one I think I need
http://www.msdignition.com/Products/Accessories/Tach_Adapters/8910_-_Tach_Adapter.aspx
I'm running a 350 that's carbuerated, msd 6al, unknown mallory dist. (It does have a 4 wire plug that connects with the msd box i believe)and a blaster 3 coil, with no magnetic crank trigger. And I'm pretty sure I'm triggering the box with the white wire like it says I should.
Any opinions will help, thank you.
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And also I have triple checked that the setting on the tach is set to 8-cylinder and i believe I even tried with the old tach set to 6 and 4 cylinder just to see if it worked.