1984 GM V6 2.8L 173ci - has Knock Sensor??? If so how to test?

Question

I've got an 84 Pontiac Firebird (garage queen with 130k mi) that has annoying ping/clatter/knock at light throttle accelleration. In fact its' pretty much had it for years now. I've recently performed a tuneup including O2 sensor. Couple years ago the TPS was replaced. Everything appears to be mechanically in order.

I wanted to investigate the EGR and Knock Sensor next. My Haynes book only references a Knock Sensor but no details.

Q: Does this car/engine have a Knock Sensor to aid with electronic spark control? (It does not have a vacuum advance - only the wired (electronic?) advance cntrl to the distributor)

Q: If it does have a sensor - Where is it located and How do I Check/Test it?

Q: If it does not have a sensor - how does the ECM 'know' when to advance/retard ignition timing?

thanks

Shep · Accepted Answer

If this is a carbureted engine there is no knock sensor, focus on the egr.

Mike Romain · Answer

The way to test a knock sensor as far as I know is to have the vehicle fully warmed up and then take a hammer and tap on the intake manifold. If it has a knock sensor and it is working, the engine will stumble slightly when you tap on it.

I normally look for or at the heat riser valve spring when I hear one of those making a rattle or knock under light acceleration. They fail or get sticky lots. This would be a weighted flapper on one exhaust right at the manifold.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >

Ted Mittelstaedt · Answer

Make sure if doing this that the EGR passages in the intake manifold are notplugged up.Ted

1984 GM V6 2.8L 173ci - has Knock Sensor??? If so how to test?

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