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toomany MBZ 03-07-2010 10:45 AM

That item would have a pin sticking out, the magnet is mounted on the block near the vacuum pump.

byronnash 03-20-2010 04:35 PM

2 Attachment(s)
I can't find the OVP Relay. Is it under a cover or something? I don't see anything like what that photo shows on the parts store. See the images below for behind the dash and the passenger kick panel.

charmalu 03-23-2010 01:50 AM


Originally Posted by byronnash (Post 2420138)
I poked around under the car today trying to spot the pickup and magnets. I took a photo of what I think the flywheel is. I can't see any magnets on it, but I see some round holes where a magnet might go? I'm going to look at the fuses tomorrow and see if there is anything funky there. How can I test the OVP relay?

This is not the flywheel. it is on the rear of the engine bolted to the crank inside the bell housing. what you have in this picture is the balancer on the front of the engine. the holes are drilled for balancing it, there were no magnets attached here.

The pick up for the tach signal would be on the top side of the crank balancer.
Look down the front of the engine, below the fan, behind the crank pully, you will see where the pick up is. Or follow the cable from the tach amp plug on the inner fender, it will lead you to the same area.

Your car being a 84, will have the tach pick up off the flywheel. the sensor is bolted to the adaptor plate. (the plate is between the engine and transmission.) there is a flat spot on the driver side of the plate it is bolted to.


toomany MBZ 03-23-2010 12:46 PM

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Here's a pic of the front crank pulley, the magnetic pick up is highlighted in red.
I painted the end of the pin white to show what spins around and is picked up by the magnet and that is translated to rpm on the dash. One 83 and older cars.
It's still there, but it's use is a diagnostic port, so no amp is needed on the inner fender.

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