89 S10 running rich and has black smoke going down the road
DTC - 13
Oxygen sensor circuit open or no activity
DTC - 33
MAP sensor circuit error (signal high indicating low vacuum)
DTC - 54
Fuel pump circuit low voltage
Start with checking the wire leads to the O2 sensors and MAP sensor. Look for any damages to the wire harness and replace any parts damaged or faulty.
The O2 and MAP sensor take reading and sends it to the ECM to recalibrate the fuel injector pulse to adjust the amount of fuel entering the cylinders. When there is an issue to the O2 sensor or MAP sensor and even both, the ECM will be set a a factory default to run rich to keep the engine running and at times the engine may not even run. Normal fuel to air ratio is 14.7:1 - 14.7 air to 1 parts fuel and at default it could be as high as 12.5:1. Good luck and keep me posted, be glad to help you get your truck running 100% again soon and please rate. replacing the thermostat and temperature sensor would also be a good thing since the 4.3 runs best at 190".
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