tachometer problems - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

gotboost2jz · 12-15-2009, 11:15 PM

95 240sx

My tachometer is completely wacked out. It does not read the proper RPM. I'll turn the car on and at idle it will bounce between 3k and 6k and continue to do so while I accelerate. Every once in a while it drops into range but eventaully resumes bouncing everywhere again. It's completely unpredictable. The speedometer also doesnt work but that's only because i have yet to change out the speed sensor to the US unit.

Is it bad wiring, or do I need a new dash cluster altogether?

Rabboni · 12-15-2009, 11:17 PM

I cant be sure, but it sounds like you have some crazy wiring gremlins to chase

Dream240 · 12-16-2009, 08:42 AM

The tach gets it's signal from the ecu (terminal 3). So if you've got a tach problem, start tracing the wiring from there to the tach in the gauge cluster. If the wiring is good, then replace the tach unit.

The tach signal is not in any way connected to the speedo sensor. The only association is that they both use wires coming from the same harness connectors that plug into the cluster, but that's it.

g6civcx · 12-16-2009, 10:52 AM

What engine is in the car?

You can try connecting a service tach and check the output signal. If the service tach also jumps around then the problem is in the sender.

If the service tach works fine then the problem is in your wiring.

gotboost2jz · 12-16-2009, 11:37 AM

its an s13 sr
i'll just check the wiring when i return stateside. is it possible it could be a bad feed from a plug to the ECU?

g6civcx · 12-16-2009, 11:46 AM

Quote:

Originally Posted by gotboost2jz

its an s13 sr
i'll just check the wiring when i return stateside. is it possible it could be a bad feed from a plug to the ECU?

Either that or the ECU and/or cluster is bad.

afiser · 02-01-2010, 11:28 PM

i have the same problem, where is the rev sensor located? i wanted to check the wiring from the sensor to the ecu but im kinda clueless where to start.

12-15-2009, 11:15 PM	#1
gotboost2jz Leaky Injector Join Date: Jun 2008 Location: Ohio Age: 37 Posts: 145 Trader Rating: (5) Feedback Score: 5 reviews	tachometer problems 95 240sx My tachometer is completely wacked out. It does not read the proper RPM. I'll turn the car on and at idle it will bounce between 3k and 6k and continue to do so while I accelerate. Every once in a while it drops into range but eventaully resumes bouncing everywhere again. It's completely unpredictable. The speedometer also doesnt work but that's only because i have yet to change out the speed sensor to the US unit. Is it bad wiring, or do I need a new dash cluster altogether? __________________ 1995 240sx SE - 1JZ

12-15-2009, 11:17 PM	#2
Rabboni Zilvia Member Join Date: Aug 2009 Location: Fairfield, CA Posts: 230 Trader Rating: (0) Feedback Score: 0 reviews	I cant be sure, but it sounds like you have some crazy wiring gremlins to chase __________________ Baling Wire-The Duct Tape Of Champions

12-16-2009, 08:42 AM	#3
Dream240 Nissanaholic! Join Date: Dec 2002 Location: Inland Empire, California Age: 46 Posts: 2,188 Trader Rating: (8) Feedback Score: 8 reviews	The tach gets it's signal from the ecu (terminal 3). So if you've got a tach problem, start tracing the wiring from there to the tach in the gauge cluster. If the wiring is good, then replace the tach unit. The tach signal is not in any way connected to the speedo sensor. The only association is that they both use wires coming from the same harness connectors that plug into the cluster, but that's it. __________________ Don't mess with my monkey...he's loaded.

12-16-2009, 11:37 AM	#5
gotboost2jz Leaky Injector Join Date: Jun 2008 Location: Ohio Age: 37 Posts: 145 Trader Rating: (5) Feedback Score: 5 reviews	its an s13 sr i'll just check the wiring when i return stateside. is it possible it could be a bad feed from a plug to the ECU? __________________ 1995 240sx SE - 1JZ

12-16-2009, 10:52 AM	#4
g6civcx Post Whore! Join Date: Apr 2004 Location: Virginia, USA Posts: 5,764 Trader Rating: (5) Feedback Score: 5 reviews	What engine is in the car? You can try connecting a service tach and check the output signal. If the service tach also jumps around then the problem is in the sender. If the service tach works fine then the problem is in your wiring.

02-01-2010, 11:28 PM	#7
afiser Leaky Injector Join Date: Jan 2010 Location: here and there Posts: 81 Trader Rating: (0) Feedback Score: 0 reviews	i have the same problem, where is the rev sensor located? i wanted to check the wiring from the sensor to the ecu but im kinda clueless where to start.