VDO Tacho prob?

[RobWales]

Morning all,

Just wondering if anyone here might be able to assist? tried on the mobo forum a weeks ago but drew a blank!

Tacho connected to my VP AD31XD diesel engine in my recently purchased Fairline has a problem.......

When I turn on the ignition and even before she has fired up the needle spins all the way round to max (hitting the stop) and stays there even after starting and engine running smooth!

Have a four gang connector plug (back of tach) which all seems fine, two connections to bulb again fine, however there is one spade next to the four gang with nothing on and cannot see that anything as come off that!

Have checked all connections at alternator and again all seem fine!

Stumped now....any ideas welcome?

Thanks,Rob.

 

[Talulah]

The tacho spinning all the way round is usually part of the tacho test sequence at start up.
Why it stays there I don't know. Maybe it is literally getting stuck there.
Try loosening the tacho. Maybe it has become distorted.
Ideally you need to find someone who has a spare tacho so you can swap them over. That way you'll identify if it is the tacho or something else.
Having a spare spade is not necessarily an issue. Which spades are used depend upon the source of the revs signal to the tacho. i.e. Coil or Tacho based.
Have you looked at the manual?
http://www.vdo.com/generator/www/co...chometer_drehzahlmesser_uv.pdf?redirect=false
(Assuming you have Oceanline range.)

 

[RobWales]

The tacho spinning all the way round is usually part of the tacho test sequence at start up.
Why it stays there I don't know. Maybe it is literally getting stuck there.
Try loosening the tacho. Maybe it has become distorted.
Ideally you need to find someone who has a spare tacho so you can swap them over. That way you'll identify if it is the tacho or something else.
Having a spare spade is not necessarily an issue. Which spades are used depend upon the source of the revs signal to the tacho. i.e. Coil or Tacho based.
Have you looked at the manual?
http://www.vdo.com/generator/www/co...chometer_drehzahlmesser_uv.pdf?redirect=false
(Assuming you have Oceanline range.)

Thanks T,

I don't think its an oceanline Tach having taken a look at that pdf but thanks anyway, I'm not able to say exactly what it is as I forgot to get the P/N off it at the weekend, I can say though its a circa mid 90's with anolouge hours built in (i.e rotating numbers)..?

 

[RobWales]

Bump........