Tacho problem/question

[ricktutty]

hey all,

I have a question that most of you may know considering its been done many times before.

I have installed today a VDO 3" Tachometer and had all working fine in my VN S1 Sedan, tests where done on idle and slight throttle spiking to make sure it was in working order.

But the problem i face is, as soon as i finished up installing (just before taking for a drive after switching motor off) i had jumped in to take for a test drive a had started the motor, only now i have a 1 sec response and it loses signal (no rpm)... this now happens everytime i go to start the motor now. I had inspected all connections and fuses to confirm there were no blown fuses to finding nothing wrong in those areas.

Also whilst driving (motor on idle), it may suddenly recieve a signal but suddenly dropped either randomly again or when i accelerate.

My Question is, i have i done something wrong? have i missed something? and could it be possible that there is not enough power to run the tachometer?

Please do not hesitate to ask as many questions possible to find out wat i have done or on anything else that may help

i highlky appreciate anyones help prior to posting forward

 

[v6lux]

I don't know much about these after market tachos that do nothing to improve my ugnlyness or driving skills, but it might be faulty, as every Gypsie and his dog at the markets are importing fakes from China, good chance it is a failure or not suited to the Commodore!

Swap it for another one!

 

[ricktutty]

ok i got some news if it may help,

i have noticed that whilst starting the engine and race the motor straight away the tacho will follow the rpms but will only last for 1sec if that helps

 

[ricktutty]

does anyone here know anything about voltages, amps, etc, on gauges and how they are run? or wat voltages, amps, etc. run through the vn's signal wire to operate the original tacho?

because i have found out (i think because it wasnt the exact same one but very close to it) that my VDO Tachometer is a 12V? one if that helps anyone?...

 

[neet_wagon]

What have you wired the tacho to, to recieve its signal?

 

[ricktutty]

-the white? wire connected to the light fuse (DONE)
-the green? hooked to the signal wire (CONNECTED TO BROWN/RED STRIPE WIRE)
-the red! to the constant power (DONE)
-the black wire to an earth (DONE)
-the yellow? to an accessory fuse (DID NOT COME WITH ONE)

my VDO tachometer came only with black, red, green and white

also tried the passengers strut tower connection to no luck

 

[neet_wagon]

If it did not come with a yellow wire how have you connected one?
I haven't installed one in ages but from memory:

- you need a light source, white wire
- input wire connected to tacho wire near passenger strut tower
- you need an earth, black wire
- and one power source, connected to accessories

As I said, haven't played around with one for awhile, but thats how i remember doing it.

 

[ricktutty]

kool yeha thats how i exactly setted up as per pics

*EDIT* never mind about the colour of the signal i didnt have any green wire so i had to revert to brown

 

[neet_wagon]

how old is it? Looks old, perhaps its had a knock and its buggered?

 

[ricktutty]

it is old but it works pefectly had it given to me by my friends uncle that use to build VW's with subby motors and thats wat he was using