Finally broke my Tacho :)

[Ant97GTR]

Hey all,

Took my line out for a drive over the weekend and it looks like I've finally broken my tacho (stock) after all those trips to the redline On start up the tacho works fine and shows idle around the 1k mark (normal). When driving the tacho reads fine between 0-2500rpm but once the revs go past that mark it either drops to 0 or jumps all over the place. Funny thing is that when changing gears etc and the revs drop down past the 2500 mark the tacho starts reading fine again???

Now when something mech goes wrong in my car, I'm pretty good at diagnosing the prob but with gauges and other elec items I'm pretty clueless. Are the stock tacho sensors off the gearbox or do they read off a pulse from the coil packs? Also are there simple things I can check to make sure a connection hasn't come loose or something? Finally has this happened to anyone in vic and can you recommend a fix or a good auto elec?

Any info or help would be much appreciated.....

[Revhead]

As I understand it, the ECU works out RPM based on the crank angle sensor, ie it calculates the CAS's speed. Then the ECU send signals to the tacho and the tacho just shows what's happening.

I'm no electronics genius so I have NFI what's actually wrong here, but losing the tacho feed is not uncommon on R33s. I lost mine, but it stayed on zero, it didn't move no matter what. I just changed the ECU and off it went again. Maybe scab someone else's ECU for a test?

[benjiman74]

Hi Ant, If it is the tacho I've got a Nismo replacement lying around if you are interested $200. You'll obviously lose the standard boost guage but i presume you were running more than .7 bar anyway.

[Ant97GTR]

Revhead.....thanks for the info......hmmm interesting considering I have a wolf 3d replacement comp!!! I have my stock ecu so I might spend some time swapping them over to see if it is the comp...thanks I'll look into that (at least I'll be able to determine if it is the ecu or something else)

Benjiman74......very interested in the nismo item if it does end up being the tacho, if you could hold onto it for a couple of days till I check ecus etc that would be great otherwise if you get an offer you are happy with before that, so be it.

[benjiman74]

no worries ant, see how you go, its not listed anywhere for sale just part of an unwanted collection of bits I've acquired

[GTRgeoff]

Ant mine does the same, even after I changed to PFC.

Apparently the tacho can be pulled out easily and the tracks cleaned as they get a bit corroded or something. Hearsay only but worth a look. Unfortunately I'm snowed for time to check but will do so after I get back from OS on 5th Dec

[paulr33]

hey ant i had this exact same problem. past around 2500rpm it would go nuts. i found it was when i got my apexi rsm installed, the stock rev output signal is set to about 3000 rpm so when it triggers that it somehow made the tacho go nuts, no idea why. you can use the rev output relay on the rsm to control things like shifts lights etc but mine wasnt hooked up to anything but the setting was still there, go over 3000rpm bang tachno goes psycho as no idea why. fix was to set the rev output value to 8500rpm as i can never reach that

not sure what it could be in your case but i have seen what you are talking aobut

also when it would happen the hicas light would flash for some random reason too