Land Rover Repair: tach drive, 1997 land rover disco, rover models, strange sound

Question
the tach on my 97 disco has been making a habit of being stuck on zero than jumping back to what seems " normal" untill I get below 1,000 rpm's than back to stuck. While in the " stuck " position I'm getting a strange sound from the engine compartment, almost like a vacume leak, but not quite. My question, where does the tach drive originate from so I can trouble shoot from point A. Thanks for your time...

Answer
In some Rover models the tach is driven from the alternator.  A few take the tach signal from the ignition.  The rest get the tach drive from the engine control unit.   Did you know that Land Rover has a website where you can access all the dealer service information for your car on a daily subscription basis?  It is www.landrovertechinfo.com  In the USA it costs less than $20 for a day's access which is a real bargain considering you can view every single piece of service info for your vehicle direct from the source.

You can punch in your serial number and get the exact wiring right there.

Best of luck to you with this project

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