Coyote alternator not working

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12-23-2014, 04:44 PM
rcotner

Coyote alternator not working

I installed the specified alternator with my Coyote engine in my 33 hotrod. Engine runs great, the alternator, not so much. The Coyote instructions say to connect the yellow wire from the engine alternator harness to IG pin on the alternator as well as the power cable back to the power distribution post. All that done and still no juice from the alternator (12.2 volts off, 12.05 running). I suppose the alternator could be bad but it is a rebuilt and tested unit from Autozone. Any ideas, did I wire it wrong? Any help much appreciated as always!!!
12-23-2014, 06:12 PM
77233349975

it took me three new alternators before I got one that worked from auto zone. take it back and get them to test it
01-07-2015, 02:57 PM
rcotner

I now know what is wrong. The alternator is fine but the 12v ignition signal from the coyote engine harness is not there. Has anyone with a coyote engine seen this or know what to look for?
01-07-2015, 05:42 PM
rcotner

Quote:

Originally Posted by rcotner

I now know what is wrong. The alternator is fine but the 12v ignition signal from the coyote engine harness is not there. Has anyone with a coyote engine seen this or know what to look for?

I just got off the phone with Ford Racing tech support. He said the voltage on that lead (VBAT MON in the engine harness) is variable and controlled by the computer. He said that for a non-stock alternator application I should not use the VBAT wire in the engine harness and that I should connect a wire to the ignition switch to deliver the needed 12v. So, I think it is all clear for me but it is contradictory to coyote engine fitment manual from FFR. Just and FYI of others are having the same confusion.