Looking at Chilton's and Hayes books for my wire/pinout for my 91 5.7 TPI isn't matching up. I am trying to wire the autometer air/fuel guage to my ecm. The connecter near the sensor itself is purple as the manual suggest and also tan, BUT when I go to the ecm and look I have (2) 32 pin connectors with "D" labeling. I then look at both and see NO purple wire in pin D7 as one of my books suggests. ANY help is appreciated. When I turn the key for "switch" power without starting the engine the guage is off, should I get atleast something without the engine running? Thanks for replies.

 

hooking up any after market gauges is best to do away from the ecm. that splice near the ecm could cause problems and may damage the ecm or give it false readings. I have always tried to splice in the leads of the different sensors as not damage the orginal wiring harness and making it easier to return to normal if a problem does arise down the road.

 

Armac is correct! Wire it in closer to the O2 sensor itself. Much easier, and probably a bit more accurate.