Erratic tach

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1hotboss

Well-known member
Joined
Jun 12, 2015
Messages
55
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Location
Canada
My Car
1970 Boss 302
Hi,

My 8000k tach seems to be jumpy as I accelerate. It is fine on start up and at low speed but as I step on it and it begins to reach 3-3.5k it begins to become jumpy...and eratic and seems to stop at the 4-5k mark and will not go above this.

Any suggestions on causes and fixes

Thanks

 
Hi,

My 8000k tach seems to be jumpy as I accelerate. It is fine on start up and at low speed but as I step on it and it begins to reach 3-3.5k it begins to become jumpy...and eratic and seems to stop at the 4-5k mark and will not go above this.

Any suggestions on causes and fixes

Thanks
What kind of setup do you have and where is it getting its signal from?

Sounds like its losing the signal at the higher rpms.

 
Hi,

My 8000k tach seems to be jumpy as I accelerate. It is fine on start up and at low speed but as I step on it and it begins to reach 3-3.5k it begins to become jumpy...and eratic and seems to stop at the 4-5k mark and will not go above this.

Any suggestions on causes and fixes

Thanks
What kind of setup do you have and where is it getting its signal from?

Sounds like its losing the signal at the higher rpms.
Stock distributor with petronix 2

THanks

 
would the rocketman conversion help with the bouncy tach
I would say that it would since it probably reacts to the signal better.

You also avoid your car dying if the tach fails since the factory tach is an integral part of the ignition circuit.

Are you also using a Pertronix (1.5 ohm coil) with the Pertronix 2?

 
My 8k tach was very bouncy and did not move past 4k. I did the Rocketman conversion and now it works perfectly. It is well worth it and no one will know it has been modified.

1971 M-code Mach 1

 
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