240Z tachometer

[Ronald]

Hi,

I received some great past help from this forum regarding an engine miss after installing a Pertronix electronic ignition. After trying all of the suggestions, the mechanic changed all the connectors to the tach and the miss finally went away. I purchased a used under dash wiring harness for the connectors.

The tach still had a problem with cutting out above 4500 rpm during fast acceleration like it did before. The mechanic hooked up a different tach and it did the same thing - cutting out above 4500 rpm. Now the tach doesn't work at all but the car still does not miss; the needle doesn't move at all. The mechanic will try the other tach next week to see if it still cuts out above 4500 rpm, or does not work at all.

My 240z runs much better with the Pertronix system but this tach problem is very frustrating. If the tach problem can't be fixed I am thinking about removing the Pertronix and putting the z back to stock.

Any ideas on the tach problem?

As an added note the mechanic replaced all of the dash light connectors with connectors from the used harness and fixed a long term problem with intermitant dash lights.

Thanks in advance for the help,

Ron

[tlorber]

I had my tach guts replaced by a speedo shop (after trying to fix it myself). They installed new electronics which acknowledge any wave form (points, pertronix, electronic dizzy, whatever). This enabled original original appearance with the accuracy of modern electronics.

Only problem is that it cost $170.00. Expensive, I know, but I can't stand driving without a tach.

[Inf]

I tried the Pertronix setup 6 years ago, and my tach started flaking out. It would bounce around like crazy.

Problem went away after going back to the original points setup.

I know others have had no problems with the Pertronix setup, but that was my experience.

Also, it's my experience that intermittent dash lights are the result of either a bad fuse block (corrosion, melting of the plastic parts holding the connections together), or a bad combination switch.

Edited July 1, 2010 by Inf

[Ronald]

Hi tlorber,

Thanks for the info. Can you tell me how to contact the speedo shop. I live in central California and would mail or hand deliver my tach for the mod. I would gladly spend the $170 so that I can have a working tach.

Ronald

[Ronald]

Hi Andrew,

Thanks for the info. If I cannot get the tach working soon I will probably go back to stock points also.

Ronald

[mlc240z]

Andrew and Ronald,

Please share the info on the address for a successful rebuild.

[d240zx2]

I guess I'm one that didn't have tach issues after converting to Pertronix. I do have a tach that seems to be about 500 rpm optimistic, though. 'Course it was that way before the changeover.

[tlorber]

North Hollywood Speedometer and Clock. Located in ....North Hollywood.

Here's the web site:

http://www.nhspeedometer.com/

[Ronald]

I guess I'm one that didn't have tach issues after converting to Pertronix. I do have a tach that seems to be about 500 rpm optimistic, though. 'Course it was that way before the changeover.

I had the same problem with two seperate 240z tachs, one was 200 rpm off and the other was 600 rpm off. The one that was 600 rpm off had just been rebuilt. I got a schematic of the 240z tach off of this forum. When I gave it to my mechanic he was able to adjust both tachs so they read correctly. If you want a copy and can't find it in the forum, let me know and I will find a away to get you a copy.

[Ronald]

North Hollywood Speedometer and Clock. Located in ....North Hollywood.

Here's the web site:

http://www.nhspeedometer.com/

I will be contacting them this week if the mechanic cannot get one of the two tachs I have to work correctly. Thanks.