My tach has been intermentedly having signal interference. Which is caused by my trailing coil firing irregularly. Today I tried to fix the interference by wrapping every thing in electrical tape. Now it worse. The tach now is reading twice as fast aka ifif the engine speed is 3k the tach would read 6k.

I think the interference is coming from the harness itself. As I have bundled the trailing wires together.

What do you guys think? Sprint Re on a s4 rx7.

 

change the tacho setting to 4 pulse

 

The tach isnt wired to the haltech. Its the coil. That is firing irregularly. Im using the tach as the measure of malfunction. The tach is telling me what the trailing coils are doing, which since i last drove the car; firing at twice the rate.

 

Log trigger at last home. If it's consistently at 12 you have an issue with the coil or tach. If it's not consistently at 12, you have noise in the trigger input to the ECU.

 

Fixed. Yellow/Orange looks to much like Yellow/Red.

 

Ok. Its not mis-wired. How do i go about identifying the noise source? How do i isolate the noise? My whole harness has been shrink wrapped i really dont wanna undo it but if i have to i will.

Is the CAS supposed to be grounded in a particular way?

The problem is intermittent. So im having a hard time isolating the suspect.

 

check to see if the trailing coil pack is bad by swapping it out. i know they dont tend to go bad, but sometimes they do. you have to rule that out.

 

sort of confused.
Is it the trailing coil firing you are worried about or the Tach being screwy?
If it is the Tach,and you have the stock coil setup,are you getting signal from the bullet connector on the trailing coil?
If so,try putting a jumper wire to the Leading coil bullet connector as that give you tach signal too..