Vaughan Posted April 29, 2020 Report Share Posted April 29, 2020 If you have more than one output set to tacho you will run into problems, turn off that second tacho output smason 1 Quote Link to comment Share on other sites More sharing options...
smason Posted May 1, 2020 Author Report Share Posted May 1, 2020 So after lots of research, I hardwired the output of the ECU directly to the tach. It still doesn't work. I am seeing a DC voltage (6v) on this wire. Does that make sense? Quote Link to comment Share on other sites More sharing options...
Vaughan Posted May 1, 2020 Report Share Posted May 1, 2020 A DC voltage of 6V makes sense as 12V at 50% duty cycle when averaged is 6v, Have you made sure that only AUX6 (assuming that is the one wired to the tacho) is set to Tacho? your earlier picture suggests that AUX Ign 7 is also set to tacho, if it is then turn it off. Quote Link to comment Share on other sites More sharing options...
smason Posted May 1, 2020 Author Report Share Posted May 1, 2020 I've shut them all off, noticed 4-6 had some sort of limitation. I've pulled the tacho right out to eliminate harness issues. Fed direct power and Aux 1 set to tacho. Still not working. I'm going to try and borrow an additional tach from a friend but who knows. Quote Link to comment Share on other sites More sharing options...
Vaughan Posted May 1, 2020 Report Share Posted May 1, 2020 Was that power, ground and aux 1 set to test pwm all connected to it? Quote Link to comment Share on other sites More sharing options...
smason Posted May 2, 2020 Author Report Share Posted May 2, 2020 I took the tacho right out of the cluster, gave it +12v , GND, and Aux 1 as tach/ pwm. No luck on either. Trying to find a 3rd gauge cluster. Quote Link to comment Share on other sites More sharing options...
smason Posted May 8, 2020 Author Report Share Posted May 8, 2020 I have a new tach, and it sort of works. Is accurate with a .93ish multiplier, but it randomly pegs. Looks like it's just an issue with the cluster. Now to find a good tachometer. Note for future USDM 240SX S13 cars. : YOU MUST USE A DOHC TACH. Speedometer is the same between the two. Waiting on the vss, should be here today. Then we'll see if that's working or not. Common issue with s13 clusters. Quote Link to comment Share on other sites More sharing options...
Vaughan Posted May 8, 2020 Report Share Posted May 8, 2020 with regards to faulty tachs the mr2 ones are known for dying and can commonly be fixed by replacing the electrolytic capacitors Quote Link to comment Share on other sites More sharing options...
smason Posted May 14, 2020 Author Report Share Posted May 14, 2020 The VSS did not fix the speedometer. I built that RC circuit fine. Trying to find a friend with an oscilloscope. Quote Link to comment Share on other sites More sharing options...
Vaughan Posted May 22, 2020 Report Share Posted May 22, 2020 Just a thought, when sending that aux signal through teh RC circuit through the dash are you sending it through the wires which used to go to the gearbox sensor or through the factory speed input into the ECU wires? In my Stagea the speed wires to the dash run the length of the gearbox and go in to a plug in he engine bay then through the body loom to the dash, a modified version of this signal is then sent from the speedo across the car t the ECU as a speed input for the ECU. This means that there are two speed wires for the dash cluster, one in and one out (+ the signal grounds of course). smason 1 Quote Link to comment Share on other sites More sharing options...
smason Posted May 25, 2020 Author Report Share Posted May 25, 2020 Well I have an update! I've been working almost non stop so I've been very busy. But this will be the finale - I think. I have just been driving with the tachometer which is less twitchy, and no speedometer. Well as legend has it, last night I was driving to work, and the speedometer came to life! I changed nothing. I did nothing. The RC circuit works and it is kind of accurate. The multiplier works but the speedo is just 'out' at higher speeds. No fault of the G4. This is a classic representation of a USDM 240sx and it's troubles. Vaughan 1 Quote Link to comment Share on other sites More sharing options...
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