DoctorBill Posted July 10, 2009 Share Posted July 10, 2009 My tachometer in my '95 4x4 Pathfinder (just bought used) goes ape sh*t about half of the time. Flips around like Mad, Vibrates strongly, or simply goes all the way to the top end slowly and inexorably until I kill the engine - then it is OK. The other half of the time it works fine. So - I would conclude that the Tachometer itself in the Dashboard is working OK and that some signal feed is the culprit. Question - where is the feed wire (at the coil?) ? What is the wire color? I was told by some mechanic that the major culprit is one of the wires attached to the positive battery post that supplies the Tach's power. I have cleaned them and reattached those wires, but still, the Tach goes nuts once in a while - especially when I fart around with the Overdrive Button on the shift lever. Could some spurious electronic signal be being injected into the 12v charging system? Changing gears seems to disturb the Tach. With all these clues, all you Sherlock Holmes types out there ought to be able to finger out what is wrong.... Let's hear from the geniuses on this forum. DoctorBill Link to comment Share on other sites More sharing options...
unccpathfinder Posted July 10, 2009 Share Posted July 10, 2009 sounds like my 87 when the wire was loose on the dizzy...it's flop around like crazy then work fine nad it was always random and happened whenever it wanted to...i clipped it and crimped on a new spade and it worked fine ever since...see what the others suggest b/c sometimes im off... Link to comment Share on other sites More sharing options...
adamzan Posted July 10, 2009 Share Posted July 10, 2009 It is also known on the 95's for the tach itself to go bad. On the 95 I bought a few months ago the tach spazes around like that but if you whack the dash it'll work for a bit then die. Link to comment Share on other sites More sharing options...
Precise1 Posted July 10, 2009 Share Posted July 10, 2009 Yep, the 94 & 95 electronic clusters are known to have issues. I have had a speedo fail (completely0 in 1 and the tach tweek out as you describe in the other. I removed the clusters, built one fully functioning one and put that in my keeper truck. Oddly enough, the tweeker tach seems to have adjusted it's errant behavior and functions once again. Try removing the cluster, checking the connections and tightening the brass screws in the back (ground points). This may help. I believe the voltage regulator is also a culprit so if you know electrionics, check that. Otherwise, get a working unit from someone parting out a truck or a junk yard and install it... B Link to comment Share on other sites More sharing options...
DoctorBill Posted January 9, 2010 Author Share Posted January 9, 2010 Does anyone have one or know where I can find the WIRING DIAGRAM for the '95 XE-V6 TACHOMETER ? I would like to see if it goes thru the Computer or if I could find the wire behind the Instrument Console, cut it and replace the wire to the Coil. I'd like to know if it need more than just the one wire to the Coil, a good ground and a good positive power source. Maybe I could bypass the problem area instead of having to find it in all that damned wiring harness. DoctorBill Link to comment Share on other sites More sharing options...
Terrano1992 Posted January 10, 2010 Share Posted January 10, 2010 Does anyone have one or know where I can find the WIRING DIAGRAM for the '95 XE-V6 TACHOMETER ? For example, download EL part of 1994 FSM here. Look at page EL-38 and EL-39 ("Meter and Gauges - Wiring Diagram"). Link to comment Share on other sites More sharing options...
Precise1 Posted January 10, 2010 Share Posted January 10, 2010 Does anyone have one or know where I can find the WIRING DIAGRAM for the'95 XE-V6 TACHOMETER ? You can download the entire FSM here... http://www.nissanpathfinders.net/forum/index.php?showtopic=5410&st=0&p=457867entry457867 Try removing the cluster, checking the connections and tightening the brass screws in the back (ground points). This may help. Did you ever try that?? You cant lead an old dog to water, or something like that... B Link to comment Share on other sites More sharing options...
DoctorBill Posted January 10, 2010 Author Share Posted January 10, 2010 (edited) For example, download EL part of 1994 FSM here. Look at page EL-38 and EL-39 ("Meter and Gauges - Wiring Diagram"). I downloaded the FSM as many pdf files. Thanks for that lead...I tried looking in the Index under Tachometer and Speedometer - nothing. Not Tachometer or Speedometer or Instrument Cluster....."Combination Meter"...Amazing. Now....which wire goes to the Coil - Number 33 (White) or Number 42 (Blue) ? Number 17 is +12v (white/Blue)....got that. Goes thru the SMJ - SUPER MULTIPLE JUNCTION....on the foldout pdf file....CONFUSED. How does the SMJ diagram work ? What do the numbers on the bottom black line refer to ? DoctorBill Edited January 10, 2010 by DoctorBill Link to comment Share on other sites More sharing options...
Terrano1992 Posted January 10, 2010 Share Posted January 10, 2010 Now....which wire goes to the Coil - Number 33 (White) or Number 42 (Blue) ? None of above. Pin 42 (connector "33I") is externally connected to pin 21 ("14I"), and both connected to the ground. Ground circuit: pin 42, black wire, SMJ pin L15, black wire, joint connector "C" (212M), black wire, body ground points 232M and 202M. "Ignition signal" from coil goes to ECU (pin 3). ECU, in turn, sends processed signal to tachometer (from ECU pin 2 to tachometer pin 33). There are no direct connection between coil and tach. Goes thru the SMJ - SUPER MULTIPLE JUNCTION....on the foldout pdf file....CONFUSED. SMJ is a large connector behind the fuse block (white square, with bolt in center). It connects instrument harness with main harness. How does the SMJ diagram work ? What do the numbers on the bottom black line refer to ? Look at "SMJ box" on the top of this diagram (marked as "VG"), not a bottom ("KA"). This diagram shows all wiring versions, both for VG30E- and KA24E-equipped vehicles (also trucks and wagons, auto/manual transmissions). You need to select appropriate fragment using corresponding symbols (VG, KA, F, R, T, W). Symbols "33I", "267M", "212M" shows connector location on the body (or engine) harness. Look at "Harness layout" (EL-79..EL-94), you can find them here. Don't blame Nissan - their diagrams are relatively easy to read and understand. If you doubt, you can try to read Peugeot diagrams (and really screw your brain... ). Link to comment Share on other sites More sharing options...
DoctorBill Posted January 12, 2010 Author Share Posted January 12, 2010 "Ignition signal" from coil goes to ECU (pin 3). ECU, in turn, sends processed signal to tachometer (from ECU pin 2 to tachometer pin 33). There are no direct connection between coil and tach. So....the Tachometer signal comes from the Computer.... Do you know which wire feeds the coil signal to the computer - i.e. the pin number of the computer? My Tach works for a while, then freaks out, then just slowly moves up and pegs, then drops to zero, doesn't respond, then freaks out, then....on and on. One should be able to trace out where the problem is occurring. Now that I find the computer is involved, one more variable is added. This HAS to be solvable ! DoctorBill Link to comment Share on other sites More sharing options...
adamzan Posted January 12, 2010 Share Posted January 12, 2010 I can almost guarantee that it is the tach itself. This is very common on the 94-95 pathfinders. Link to comment Share on other sites More sharing options...
Terrano1992 Posted January 12, 2010 Share Posted January 12, 2010 (edited) So....the Tachometer signal comes from the Computer.... Do you know which wire feeds the coil signal to the computer - i.e. the pin number of the computer? Coil signal schematic diagram is shown at page EF&EC-90 ("Engine Fuel and Emission Control System", EC.pdf). Trace circuit from ECU pin 3. But if you have problem in this circuit, you should get a diagnostic trouble code 21 ("Ignition signal") from ECU. If not - probably, coil "feedback" circuit is fine. Me think, tacho signal generation inside ECU based on signal from CMPS (Camshaft Position Sensor). This is more precisely and robust way. At the same time, ignition signal monitored by ECU to detect misfire and prevent cat damage (unburned fuel into cat). x2 to adamzan - tach itself is the culprit in most cases on 94-95 Pathfinders (with "round" dashboard). Edited January 12, 2010 by Terrano1992 Link to comment Share on other sites More sharing options...
Kyle94 Posted May 7, 2010 Share Posted May 7, 2010 (edited) Coil signal schematic diagram is shown at page EF&EC-90 ("Engine Fuel and Emission Control System", EC.pdf). Trace circuit from ECU pin 3. But if you have problem in this circuit, you should get a diagnostic trouble code 21 ("Ignition signal") from ECU. If not - probably, coil "feedback" circuit is fine. Me think, tacho signal generation inside ECU based on signal from CMPS (Camshaft Position Sensor). This is more precisely and robust way. At the same time, ignition signal monitored by ECU to detect misfire and prevent cat damage (unburned fuel into cat). x2 to adamzan - tach itself is the culprit in most cases on 94-95 Pathfinders (with "round" dashboard). I have this same problem on my 93 but most of the time the tach doesnt work at all... And sometimes ill look down and it will be working jsut fine... doesnt matter if i hit the dash or a bump.... can some sugest what i should do? i hate not having my tach when i have my stereo turned up. Edited May 7, 2010 by kyleky07 Link to comment Share on other sites More sharing options...
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