RPM gauge drops

[duh2150]

OK so, I had to move my battery to the back, I'm guessing this the the cause of the problem,

but the rpm gauge drops to 0 at idle and on acceleration but if I give it a little bit of gas it works, fine sometimes it bounces up a little bit so I know its working and getting signal, I think the current is too low to run it

I was wondering if anyone else had this problem

[dGALANTc]

that doesnt sound like a batt relocation problem. if you are getting power everywhere else i dont see why the tach alone would be affected.

[4g63lover]

I bet the cluster is out of whack. I'd look into that. You moving the battery is not going to mess with the tach.

[duh2150]

i don't know, the rpm gauge was fine before, its strange, if is not the battery it might be the ecu

[dGALANTc]

i saw you said you had a prob with the harness? think it could be something like that?

[duh2150]

the gauge reads right it just drops out like a loose wire, yeah i had a problem with the harness i sent it back and then i checked it like 5 times

[duh2150]

i think either i have a bad ecu and the dam thing only shows some rpms and dies out or i need to get like a ignition failure sensor or something off an evo

i plugged the galant ecu in and the rpm gauge worked fine

[Stewi]

its a bad ground wire somewhere. This used to happen to me with the speedo and the tach, both intermittently and never both at the same time. I went thru all my ground wires, cleaned them, added 2 seperate 2awg wire grounding cables in the engine bay, it never happened again.

[duh2150]

well i just kinda fixed it i disconnected the pin 58 tach signal output, i just unplugged the whole connector and it didn't drop out anymore, I'm thinking somethings wrong with the harness maybe? does anyone know where pin 58 goes from the evo8 ecu to the galant harness?

the wire goes from signal output (evo8) to pin 43 engine ignition signal (galant)
is this how its supposed to be wired??

http://www.roadraceengineering.com/evo/tech/EVO-ecuwiring.htm