Cylinder Miss - bent pin
#1
Cylinder Miss - bent pin
4.3L in a '97 S10 was missing after a head gasket replacement. Cylinder 5 was not firing (code 305). Compression tested to about 155. Distributor cap, rotor and wires were new. Spark was reaching spark plug. Ran Seafoam through thinking maybe an injector had clogged but that wasn't it. After running it with the miss, pulled plug 1 and 5 to compare the two. Plug 5 was very dry with no real carbon deposit to speak of and no gas smell. Deciding to go after the injectors, on pulling the electrical harness from the injector we found 1 bent pin on the cylinder 5 circuit. VERY CAREFULLY straightened the pin and CAREFULLY reconnected the harness. Ensure when seating the harness on top of the injector that you set it in and seat it with even level pressure (not cocked off to one side). There is enough play in the connector to allow the pins to be bent and still lock down. The harness connector is directly behind the throttle body and is about 1.5 inches by 2.5 inches. Hope this helps those with anyone having a consistent miss on one or more cylinders. The photos show the bent pin.
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