I have an 86 rx7 and when i start the car the tach will jump up but then die right after. Also whenever the car is in motion there is beeping noise! i have been trying to read into how to fix this problem and believe the two problems might be connected? I have tried and checked just about everything i can think of but nothing seems to work! any help would be greatly appreciated!!

 

Just buy a new tachometer for an S4 and it should fix the problem unless there is some type of wire shorting out. The beeps mean something, there are different patterns it will beep in and they all mean different things I believe. The bulbs could just be blown in the tach too.

 

To test the tach take a rather long jumper wire and jumper the two short lengthed Black wires coming out of each coil (one Black wire on each of the leading and trailing coils). This will provide a signal from the leading coil to the tach instead of the trailing coil, which is normal. If the tach works properly with the jumper installed then the problem is either the trailing coil or the wiring from the trailing coil to the tach.

 

I tried the jumper wire and it worked! i replaced the trailing coil so i assume its in the wiring? how can i fix this? or is there anything wrong with using the test connector to get power to the tach?

 

Have you tried to verify if the trailing coil fires or not by checking for spark? If the trailing coil works, but it does not send a signal to the tach as it should, then the jumper wire from the leading coil could be used to get an accurate tach signal.

 

How would you test for spark? I have a voltmeter, i just would not know where to test on the coil.

 

SATCH!!!
I got the same problem too..
so Please tell me!.If I jumper the Bullet connectors(together)..is that supposed to fix the bounce and bad tach signal from the coil?
I have tried to fix this like 6 times..different coils,speedo cluster,etc..
It still does it!
thanks man.Dave.(and a Bump for the OP!)

 

Jumpering the bullet connectors just allows the leading coil to provide the signal read by the tachometer rather than the trailing coil which occurs under normal circumstances. For some strange reason the trailing coil will work but the tach signal is corrupted so using the jumpering technique is doable. If the trailing coil has been shown to work then jumpering is okay if it seems it's the only apparent way to to restore a working tach.

 

I'll give it a try after the ICE Rain stops..(supposed to be shitty today!)

 

Hey, i had the same freakin thing happen, its annoying as hell i know! tac would bounce around and LOVED to sit on the redline so i can hear the buzzer all dam day. now before you tearin the rx7's POS dash apart and do all that solderin business, check all the wiring on the trailing coil pack. unplug the two plugs and make sure all connections are good. and make sure the trailing coil is bolted down tightly!!!! that was what happend to mine, such a stupid easy fix my tach is solid strong now doesnt waver a bit.

hope this can find your tach probs. and if all else fails, cut its wires and buy aftermarket i guess

 

PS bolting the trailing coil pack down is grounding it.

 

hey thanks alot it helped alot, the jumper wire saved my tach and my ears! i tried new cluster and new coil, must be the harness oh well itll do