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Art & Volvouser, regarding the speedo in my friends '87 740 Wagon that read 5x high, -I didn't have time to swap the instrument cluster. I just picked up the cluster at the salvage yard and dropped it off to his house (a couple months ago). Knowing him, he probably hasn't installed it yet. However, I would agree with your assumption that the odometer and speedometer are having signal communication issues (either a bad/noisy output signal or a poor phase lock on the odo input). Since the speedo reads correctly, it's probably not an issue with the impulse sender. The car does not have ABS brakes (just a regular '87 wagon), and shouldn't have a signal divider. If the replacement cluster doesn't solve the problem, I'll just grab the proverbial "ferrite salt shaker" and sprinkle some inductive chokes throughout the vehicle. (hey, it could be electrical noise from the fuel pump or ignition being picked up on the impulse sender line, and the speedo is smart enough to filter it out and the odo isn't)
Just out of curiousity, how many Engineers and Electronics Techs do we have on this board??? There seem to be an unusually high percentage versus the typical demographics that I'd expect to see on a vehicle forum.
God bless,
Fitz Fitzgerald.
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'87 Blue 240 Wagon, 247k miles.
'88 Black 780, PRV-6, 145k miles.
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