Having been clued in by RBob that the Spark Latency table is different between CAmaros and Corvettes, I changed my baseline to ANHT instead of AUJP; since I'm running a Corvette ignition system (i.e. large cap distributor). I did that instead of just updating the spark latency table in case there was something else about my hardware setup that required the ANHT code.

Any rate, I'm now getting a code 42 set each of the three times I've driven the car since the update. I suppose I need to put the AUJP-based cal back in to see if it still sets the code. But, if AUJP doesn't set the code, what gives? Is there something else about ANHT that screws around with the EST circuit? It gets set while I'm driving down the freeway at constant speed- the SES light simply comes on out of nowhere.

I've checked the chip insertion to make sure it's connected well. I even reburned another chip with the same cal in order to rule out a faulty burn.



By the way, having input all of my AUJP mods into the ANHT, the car actually runs significantly stronger. Spark and fuel are the same between the two (after my mods). So I'm not sure what else is different between these two baselines (that I can't see in Tunercat), but whatever it is, this car definitely likes the ANHT better.

 

Are you sure its code 42 and not code 62? Code 42 sets when the distributor bypass is unplugged when you set the timing. A code 62 (high oil temp) happens when you use a Corvette PROM because f-bodies dont have the oil temp sensor. That's all I can think of.

 

Check your base timing. If it's off enough, it'll throw that code. Ask me how I know.

 

Kevin, yup. It's a 42 for sure. The scanner gave it. It also displayed the text "EST Spark Timing Error"
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Verified that my timing is 10° both at the distributor as well the initial setting in the cal.