Tech article says code 43 is low voltage at electronic spark control. Other info has code 43 a knock sensor problem. Can anyone clarify.

Also, if it is low voltage at ESC, could new alternator be the problem. Seems at time like it just isn't putting out enough.

Thanks.

Bill

P.S. - This is on the '87 T/A (LB9)

 

Haynes (condensed to save my fingers):

ESC is designed to retard spark timing by up to 20* to reduce spark knock - this allows engine to use max spark advance to improve drivability and fuel economy.

Knock sensor sends voltage (8-10 volts)to ECM when no knock is occuring and ECM provides normal advance. When knock sensor detects abnormal vibration(spark knock), the ESC module turns off circuit to ECM, and ECM then retards EST distributor until knock is eliminated.

Failure of the ESC sensor signal or loss of ground at the ESC module will cause the signal to ECM to remain high, resulting in ECM controlling the EST as if no knock is occuring, therefore no retard will occur, and knock may become severe under heavy engine load. At this point, ECM will set 43.

Loss of the ESC signal to the ECM will cause the ECM to constantlt retard EST, resulting in sluggish performance and cause ECM to set 43.

confused yet? me too lol

 

Actually you explanined it quite well. Sounds like what is happening. Thanks.

 

I'm an idiot - but i can type what Haynes says - glad it helped.