Tachometer not working

Technical advice Q&A

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TheDampMan
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Location: Stoke on Trent
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#1 Tachometer not working

Post by TheDampMan » Sun Oct 21, 2018 4:48 pm

Hi all any help would be appreciated.
My tacho has 3 wires coming out of it
Image
The car loom to the tacho has a 3 pin block with 2 white and one green wire, the 2 white wires are bridged together allowing the car to run, the green wire has a 12v supply.
The car has electronic ignition.
Since owning the car the tacho has not been connected.
I have tried connecting the 3 wires to the connector without any luck.
Steve
1969 Series 2 Roadster
BMW Isetta

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christopher storey
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#2 Re: Tachometer not working

Post by christopher storey » Sun Oct 21, 2018 6:36 pm

This is a sensing instrument of an early type. In standard form the white wire carrying the current from ignition switch to distributor is looped through a block, usually twice which is sometimes on the outside of the case, or alternatively sometimes inside the case, which provides a flux sensor to the circuit board on the instrument , showing by the frequency of its fluctuations the opening and closing of the points. The circuit board then provides this to a moving coil apparatus, the moving coil being powered by 12v from the green wire . Frequently, possibly even usually, even if properly wired these tachos will not work with electronic ignition

If you search for rvi and rvc tachos on this board you will find a fuller explanation, and suggestions about what to do

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Bfastr
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#3 Re: Tachometer not working

Post by Bfastr » Sun Oct 21, 2018 7:10 pm

Assuming thats a S2 tach, those wires are not original. maybe someone tried to convert it to work with the electronic ignition? and why are they partially stripped a half inch from the spade lugs? odd
the original had this type connector. have you opened up the tach to see whats going on inside?
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Bob F

69 S2 E-type OTS LHD

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TheDampMan
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#4 Re: Tachometer not working

Post by TheDampMan » Thu Nov 01, 2018 1:06 am

Yes I think it has been converted to work with the electronic ignition, however im having no luck in getting it to work so I need it checked over and repaired has anyone got any recommendations of who to send it to?
Steve
1969 Series 2 Roadster
BMW Isetta

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mark10337
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#5 Re: Tachometer not working

Post by mark10337 » Thu Nov 01, 2018 4:49 am

Do you know which type of electronic ignition do you have?
-Mark

1969 Series 2 OTS, Regency Red
'Life's to short to drive a boring car'

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abowie
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#6 Re: Tachometer not working

Post by abowie » Thu Nov 01, 2018 6:54 am

TheDampMan wrote:
Thu Nov 01, 2018 1:06 am
Yes I think it has been converted to work with the electronic ignition, however im having no luck in getting it to work so I need it checked over and repaired has anyone got any recommendations of who to send it to?
Speedograph Richfields in Notts. If you take the car to them with the tacho they may be able to get it working for you. My guess is it has been converted to a modern type.
Andrew.
881824, 1E21538. 889457..oops
http://www.projectetype.com/index.php/the-blog.html
Adelaide, Australia

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Topic author
TheDampMan
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Location: Stoke on Trent
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#7 Re: Tachometer not working

Post by TheDampMan » Mon Nov 05, 2018 4:27 pm

All sorted and working now :bigrin:
Red cable + 12v supply
Black - negitive
Yellow - side of coil
Steve
1969 Series 2 Roadster
BMW Isetta

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