Tach Problem? 73 TA Idling possible issue?

[DarkTactics]

Okay guys I have a question about the tach on my TA. I was adjusting the idle speed, and cannot get an accurate idle less then about 1050 or so. Well when the car is off, the tach falls back to 250 on the guage. Should it fall to zero when the car is off? Do you think that the guage is always off 250 RPM's?

Does an autoparts store sell a clip on tach, or hand held tach to check the accuracy of my in dash guage?


It's a 73 with 455 Superduty specs with a slightly more aggressive cam. Any suggestions or help is greatly appreciated.



Thanks,
Craig

[smiley]

:sorry: i can't help with that. maybe some one like the cheif who's got an older car will jump in here.

sounds like a nice car you got there!
'73 sd :cool:

[ZeusJr]

I'm sure someone sells something like a diag. tech, but even finding a small aftermarket Tach to temporarily hookup isn't to hard to do in just a few mins.

As far as dropping to 0 instead of 250. Experience would tell me it should go to 0, how ever due to age I'd be willing to bet your Tach may need some work or at least recalibrated.. :dunno:

[Chief Pontiac]

Originally posted by DarkTactics
Okay guys I have a question about the tach on my TA. I was adjusting the idle speed, and cannot get an accurate idle less then about 1050 or so. Well when the car is off, the tach falls back to 250 on the guage. Should it fall to zero when the car is off? Do you think that the guage is always off 250 RPM's?

Does an autoparts store sell a clip on tach, or hand held tach to check the accuracy of my in dash guage?


It's a 73 with 455 Superduty specs with a slightly more aggressive cam. Any suggestions or help is greatly appreciated.



Thanks,
Craig Do you have a auto or manual?

I agree with Rob the tach could be the problem.Thats why one of the many mods on my 70 is aftermarket gages.