Tach is jumping erratically?

Tiny
CRUISING00
  • MEMBER
  • 1996 INFINITI G20
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 104,000 MILES
Tach is jumping erratically. Will drop to zero and jump up to max and will continue. Does not happen at first start but after about 5- 10 minutes of driving. Do not notice any other signs and seems to run fine except for the jumping tach. Plan to do a full tune-up. Any other suggestions for this fix? Tach is now not working at all.
Tuesday, April 8th, 2008 AT 8:37 AM

1 Reply

Tiny
SQM
  • MECHANIC
  • 6,383 POSTS
Hello,

It sound like a wiring issue with the tachometer circuit.
You likely have a lose ground or a wire with cracked insulation or corrosion.

I have attached the wiring schematics. You will have to trace the wires to find the issue.

Here is a helpful article on checking wiring harness:

https://www.2carpros.com/articles/how-to-check-wiring

Please let me know of any questions.
Thank you.
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Thursday, September 16th, 2021 AT 9:01 PM

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