1991 5.0 litre tpi gm service number 01227730 dtc 43 electronic spark control failure and dtc 42 electronic spark timing failure are the 2 codes coming up. Engine runs but runs really rough with no power. Any ideas how to solve these issues and how to remove codes?? Engine has been put in a 1985 s15 been sitting for a number of years ran like a champ prior to sitting water got into tank have changed injectors and fuel pump filter etc thanks
DTC 42 Electronic spark timing (EST) circuit
DTC 43 Electronicl spark control (ESC) circuit
DTC 43 is most caused by a faulty knock sensor, or a open knock signal wire to the ESC.As for DTC 42 if you have a hard start condition this can set DCT 42 or a EST that grounded,or the ECM PROM.Also check the engine timing if it is not at specification .it can set DTC 42 and DTC 43 Near the distributor is a tan /black wire you will need to disconnect in order to time the engine.the timing should be a TDC.
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