hi 3.1 motor starts 4 about 3 sec have replaced crank sen have fuel press no check engin light could it be knock sen how can u check knock sen

Asked by juice511 Feb 14, 2013 at 07:48 AM about the 1991 Chevrolet Lumina

Question type: Maintenance & Repair

2 Answers

1,875

I always recommend that when someone replaces the crankshaft sensor, to replace the knock sensor as well, especially on the older cars, and it's not known if it's ever been replaced... since the knock sensor is nearby, just above the crankshaft sensor..... the connectors and wiring get rotten and fall apart just from handling them, or even hitting against them sometimes... mine did... several of them, including the knock sensor connector... had to retrofit to get going again... check your connectors and wiring good... i know it's probably ugly under there... i've got a '90... got it in august of 2011... the engine compartment was a solid block of grime... used a pressure washer, a 55 gal. drum of carb cleaner, and 3 sticks of dynamite to clean it up..... the wiring was a mess..... see if your big thick wire harness that wraps around the passenger side of the engine, top side, is being crushed by the power steering pump..... if it is... check it out..... and also, if it is being crushed, un-crush it to avoid future problems...... because after vibration, heat, time and grime work on it..... it might become an issue.....

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