rev counter no longer works

[fangio025]

Hello everyone, I come to ask for help on your forum because I can't find any solutions.

Véhicule Porsche TARGA 2.2T 1971

The +12V and negative are ok, the black and purple wire is ok and everything is well connected.

Photo of the engine part, there is no speed switch, is this normal?


many thanks for help me
Fangio

[edmayo]

What's been done since it last worked?

[fangio025]

the engine has been changed, but the distributor is the same.

the gray block operates the rev counter?

[edmayo]

I don't see a bracket for a large relay board cover, so this might be an early 71 with 70 wiring, in which case you might need the the tach transducer which would normally be on the relay board. Was the wiring removed for restoration? Looks to be freshly done. So before the engine change and restoration the tach worked?

[SFE]

Post some pictures of the wiring you have on the distributor and the coil.

[fangio025]

I don't see a bracket for a large relay board cover, so this might be an early 71 with 70 wiring, in which case you might need the the tach transducer which would normally be on the relay board. Was the wiring removed for restoration? Looks to be freshly done. So before the engine change and restoration the tach worked?

before the engine restoration, there was the same thing on the support,
i replaced the engine harness and the bhz box harness with a new harness.

Where to find the tachometer transducer? because here in france it is not possible to buy

Post some pictures of the wiring you have on the distributor and the coil.

I will take pictures on Monday.
on the ignition coil I have blue/yellow = +
brown - chassis
distributor = 1 black and 1 black purple

[edmayo]

So the tach worked before you replaced the harness?

[SFE]

Your engine is carb or MFI ?

[fangio025]

So the tach worked before you replaced the harness?

it also worked with the old wiring.
There was a service done by a pro, and then the rev counter didn't work.

When I saw the condition of the harness I decided to replace it with a new one, and the rev counter still doesn't work.

I don't know what the pro did, I haven't heard anything.

Your engine is carb or MFI ?

carburator

[rgupta250]

A tach transducer is only needed for MFI or Zenith carbs. If you are running Webers or PMOs then that may explain why it was removed.