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Another 740T problem, Arg

After years of faithful service my '87 740T has left me stranded for the first time, thankfully only a mile from my house so I was able to walk home. I was driving through a parking lot and the tachometer needle suddenly wigged out and was flipping all over the place for a moment then the engine simply shut off. Now it turns over fine but doesn't even try to start. I can hear the fuel pump running for a fraction of a second after I stop cranking but the tach needle now just sits at zero and doesn't budge. My first guess is the hall effect sensor in the distributor but before I spend $50 on a new one I'd like some confirmation.

Also does anyone have experience with the aftermarket hall sensors FCP Groton sells? The OEM Bosch sensor is nearly twice the cost.

Reply to
James Sweet
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I'd o some more testing first, but that's exactly the way the '87 EZK control units would fail back in '87. They had a very high failure rate for a few production weeks. If you drop the box down from its bracket by the steering column and tap the tic-tac-toe pattern on the case in the center square with the plastic end of a #2 Phillips screw driver while an assistant cranks the motor and watches the tach you may see the needle jump erratically to confirm a bad joint/component that lives right in the center of the PCB for the EZK box.

Bob

Reply to
User

Thanks for the suggestion, I actually have a spare ignition box somewhere, I should drag that out and plug it in. That would rock if it were just a solder joint, I can fix that easily enough. Is there any good way to test the hall sensor? I don't know what the pinout is.

Reply to
James Sweet

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