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

afiser · 04-19-2010, 12:39 AM

1995 240sx Base

Okay, first off. i have spent the last few months searching, using trial and error, doing anything i could possibly do to fix my tachometer. i have nothing to show for it.

I kinda have OCD when it comes to my gauges and with this one not working (the one i would use the most) it is really an upset.

But anyways, i have switched out clusters, checked the signal with a multimeter (this test seemed to have checked out, but this was a little while ago and im not 100% on the results i got), checked ECU codes, etc...

I guess my main question is where and how does the RPM signal get from the engine to the cluster? I know the cluster gets the yellow red stripe coming from the ECU, but from there im clueless.

i dont know what else to check but im determined to get this to work. so please, any help would be GREATLY appreciated.

AS240 · 04-20-2010, 07:44 PM

my friend had that problem in his s13. turns out he has crap engine grounds. check all your engine grounds and you could even make a few more. its good to have a couple extra anyways

slim_240 · 04-20-2010, 08:38 PM

i guess look up the pinout on the ecu. mines was doing the same thing and jumping around. i just kicked my ecu and it clicked back on. eventually i just fixed one of the pins.

slider2828 · 04-20-2010, 08:53 PM

It could be ECU, but mine is an SR and it sends a pulse signal to the tach... its either the ecu or the gauge... BUT it goes to the white plug to the dash from the engine harness before the ecu.... I would check those wires.... Its a white plug to the right of the glove box...

afiser · 04-20-2010, 09:20 PM

thanks for the help

5pecialist · 05-13-2010, 11:48 AM

Any luck? My tach likes to do it's own thing.

afiser · 05-13-2010, 04:35 PM

nope not really shit, works more than usual lately but i didnt do anything for it to be that way.

still doesnt work 100% right.

jasonb · 05-14-2010, 05:18 PM

Quote:

Originally Posted by afiser

nope not really shit, works more than usual lately but i didnt do anything for it to be that way.

still doesnt work 100% right.

late to the party, but whats wrong with ur tach? i put a scope on tach signal coming out of my sr20 ecu while back and it was a 5v square wave. maybe your tach can't reliably read 0-5v square wave?

(i have a aim mxl strada and it can't read 5v tach signal so i had to use a pull-up resistor on it to get mine to work).

afiser · 09-12-2010, 08:03 PM

interesting, well i have tried 2 different tach's with the same results i dont think the tach is the problem. however i do think the ecu is not giving a good signal. either that or the signal between the tach and ecu or ecu to whereever it gets the rpm is borked. so much crap to go wrong and i have no idea how to check it lol.

Slidin' Sam · 09-14-2010, 05:46 AM

Check where the tach/ecu actually reads the rpm's. maybe the sending unit is bad. my friend had this issue on his r32 (had a grounding kit too) and his tach did whatever it wanted, it would work sometimes, then other times it would act like a clock and just go around in circles. He just hooked up a defi tach and called it a day...

TFD · 09-14-2010, 08:40 AM

I hooked up my datascan and it reads revs perfect where my tacho f*cks up. Now you know the ecu works and the problem is in the wires or gauge.

Slidin' Sam · 09-14-2010, 06:58 PM

Trace wires then or borrow a one from a friend and test. If the borrowed one works then its not wiring and you will know what you have to do.

04-19-2010, 12:39 AM	#1
afiser Leaky Injector Join Date: Jan 2010 Location: here and there Posts: 81 Trader Rating: (0) Feedback Score: 0 reviews	Posessed Tachometer 1995 240sx Base Okay, first off. i have spent the last few months searching, using trial and error, doing anything i could possibly do to fix my tachometer. i have nothing to show for it. I kinda have OCD when it comes to my gauges and with this one not working (the one i would use the most) it is really an upset. But anyways, i have switched out clusters, checked the signal with a multimeter (this test seemed to have checked out, but this was a little while ago and im not 100% on the results i got), checked ECU codes, etc... I guess my main question is where and how does the RPM signal get from the engine to the cluster? I know the cluster gets the yellow red stripe coming from the ECU, but from there im clueless. i dont know what else to check but im determined to get this to work. so please, any help would be GREATLY appreciated.

04-20-2010, 08:53 PM	#4
slider2828 Post Whore! Join Date: Oct 2004 Location: San Francisco, CA Posts: 6,040 Trader Rating: (13) Feedback Score: 13 reviews	It could be ECU, but mine is an SR and it sends a pulse signal to the tach... its either the ecu or the gauge... BUT it goes to the white plug to the dash from the engine harness before the ecu.... I would check those wires.... Its a white plug to the right of the glove box... __________________ Turn and Burn!

09-14-2010, 05:46 AM	#10
Slidin' Sam Zilvia Addict Join Date: Jul 2009 Location: Japan Posts: 729 Trader Rating: (9) Feedback Score: 9 reviews	Check where the tach/ecu actually reads the rpm's. maybe the sending unit is bad. my friend had this issue on his r32 (had a grounding kit too) and his tach did whatever it wanted, it would work sometimes, then other times it would act like a clock and just go around in circles. He just hooked up a defi tach and called it a day... __________________

09-14-2010, 06:58 PM	#12
Slidin' Sam Zilvia Addict Join Date: Jul 2009 Location: Japan Posts: 729 Trader Rating: (9) Feedback Score: 9 reviews	Trace wires then or borrow a one from a friend and test. If the borrowed one works then its not wiring and you will know what you have to do. __________________

04-20-2010, 07:44 PM	#2
AS240 Zilvia Addict Join Date: Jul 2007 Location: Austin, Tx Age: 35 Posts: 683 Trader Rating: (18) Feedback Score: 18 reviews	my friend had that problem in his s13. turns out he has crap engine grounds. check all your engine grounds and you could even make a few more. its good to have a couple extra anyways

04-20-2010, 08:38 PM	#3
slim_240 Zilvia Member Join Date: Jun 2009 Location: dallas, tx Posts: 246 Trader Rating: (3) Feedback Score: 3 reviews	i guess look up the pinout on the ecu. mines was doing the same thing and jumping around. i just kicked my ecu and it clicked back on. eventually i just fixed one of the pins.

04-20-2010, 09:20 PM	#5
afiser Leaky Injector Join Date: Jan 2010 Location: here and there Posts: 81 Trader Rating: (0) Feedback Score: 0 reviews	thanks for the help

05-13-2010, 11:48 AM	#6
5pecialist Zilvia Junkie Join Date: Apr 2008 Location: (at rock bottom) Posts: 442 Trader Rating: (1) Feedback Score: 1 reviews	Any luck? My tach likes to do it's own thing.

05-13-2010, 04:35 PM	#7
afiser Leaky Injector Join Date: Jan 2010 Location: here and there Posts: 81 Trader Rating: (0) Feedback Score: 0 reviews	nope not really shit, works more than usual lately but i didnt do anything for it to be that way. still doesnt work 100% right.

09-12-2010, 08:03 PM	#9
afiser Leaky Injector Join Date: Jan 2010 Location: here and there Posts: 81 Trader Rating: (0) Feedback Score: 0 reviews	interesting, well i have tried 2 different tach's with the same results i dont think the tach is the problem. however i do think the ecu is not giving a good signal. either that or the signal between the tach and ecu or ecu to whereever it gets the rpm is borked. so much crap to go wrong and i have no idea how to check it lol.

09-14-2010, 08:40 AM	#11
TFD Leaky Injector Join Date: Dec 2009 Location: Holland Age: 44 Posts: 124 Trader Rating: (4) Feedback Score: 4 reviews	I hooked up my datascan and it reads revs perfect where my tacho f*cks up. Now you know the ecu works and the problem is in the wires or gauge.