Jump to content

Rev counter over reading


Recommended Posts

Hi guys since I got my car on hard acceleration the rev counter will jump beyond where I know the revs are. Starting yo use the car I noticed today that on the overrun it will also overread the revs in different gears.

 

Any thoughts I bought a cig lighter voltage gauge and it seems to be quite consistent so I am puzzled -is there a worm drive somewhere slipping ?

 

Thks

Link to comment
Share on other sites

  • 4 weeks later...

Hi folks I changed this today and on first startup it looked like a success but I took it for a short run and it's back to its old tricks although perhaps slightly better.

Is there something else in the system that it could be other than the rev counter itself?

Many thks

 

Andy

 

 

Link to comment
Share on other sites

Perhaps if your voltage regulator or alternator are not charging correctly the battery won't last long even when moving. It means the voltage drop sends the rev counter back to it's old tricks. Did you check the battery voltage before and after your run?

Link to comment
Share on other sites

On 18/04/2021 at 23:40, Jonny Hart said:

Rev counter is electronic, not mechanical.    The usual issue is a failing voltage regulator.

What is your battery voltage reading?

Did you do this?

Link to comment
Share on other sites

I changed the voltage regulator  today battery is fine - didn't check the voltage today but previously was about 14.4v

Are there any other possibilities  ?

 

Link to comment
Share on other sites

Ok.

Your car has a 3 pin CDI which is triggered by points.  If the points are worn or not set correctly, they can bounce which may cause the tacho to over read.  That would be more of a 'twitch' to a higher RPM, rather than a continuous over read.

 

Link to comment
Share on other sites

  • 1 month later...

I have started to suffer from this after the drive to Beachy Head.

Points look perfect, but have been in a while. Distributor showed arcing on three contacts in a line but the other three were clear (cap not fitted correctly?).

Regulated voltage is nice and smooth. Dwell angle is perfect.

Guess I'll order usual ignition service items from Matt and see what happens.

 

Jason

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...