Posessed Tach!

R

reignofone

New Member

May 1, 2010

9

0

0

hot springs

May 9, 2010

#1

• May 9, 2010

• #1

just yesterday im cruising down the freeway, 65mph 1800rpm when out of the blue the tach jumps to 4100rpm for 4 or 5 seconds, then goes back to normal for 4 or 5 seconds, then back to 4100rpm. its constantly does this but without any problems from the engine whatsoever, it runs and drives fine! any ideas on what this might be?

 

KENS89LX

Member

Mar 12, 2006

302

1

19

Cross lanes Wv

May 9, 2010

#2

• May 9, 2010

• #2

factory tach?

 

K

kingmeirl

Member

Feb 3, 2008

65

0

7

May 9, 2010

#3

• May 9, 2010

• #3

loose ground to the coil, mine does the same thing

 

R

reignofone

New Member

May 1, 2010

9

0

0

hot springs

May 9, 2010

#4

• May 9, 2010

• #4

yeah factory tach... you really think thats all it is? where do i tighten her up at? which ground wire as there are 50 under the hood

 

1987stangman

Member

Jul 12, 2006

684

24

19

May 10, 2010

#5

• May 10, 2010

• #5

reignofone said:

just yesterday im cruising down the freeway, 65mph 1800rpm when out of the blue the tach jumps to 4100rpm for 4 or 5 seconds, then goes back to normal for 4 or 5 seconds, then back to 4100rpm. its constantly does this but without any problems from the engine whatsoever, it runs and drives fine! any ideas on what this might be?

Click to expand...

When I bought by 87' it had that same issue and ended up having to buy a whole instument cluster just to get the RPM side of it out to replace the one in the car which solved my problem.

 

K

kingmeirl

Member

Feb 3, 2008

65

0

7

May 10, 2010

#6

• May 10, 2010

• #6

oh, im not sure about the factory tach. mine is aftermarket and it doubles the rpm reading when the ground to the coil is loose