Tachometer reads incorrectly.

[Ghost_GSX]

So my Tachometer is reading half of my actual engine RPM. It was working fine when I first started the car and drove it. Has anyone had this some problem before?
I have a 6-bolt swap done and my CAS is wired correctly.
Other than a FMIC everything is stock.

 

[97gst_spyder]

Power Transistor, or coilpack issues. Check that everything is getting the correct power.

 

[Ghost_GSX]

I switched Both of those with known good ones and there was no change. How would I test to see if its getting correct power? I have a multimeter but I never knew how to use it.

 

[97gst_spyder]

Umm, I found it one time about 4 months ago... I'll look tonight for you.

 

[Ghost_GSX]

Any Help will be greatly appreciated.

 

[phunny]

Do you have an SAFC or Link?

 

[Ghost_GSX]

Do you have an SAFC or Link?

Not yet. Plan on it when I get the money to get an E-prom and Link.
The only reason I know my Tach is off is when my friend hooked up his obd2 scan tool and my idle was reading higher than the gauge. We drove it around with it still hooked up and compared both readings and the scanner was reading double the tach.

 

[phunny]

Not yet. Plan on it when I get the money to get an E-prom and Link.
The only reason I know my Tach is off is when my friend hooked up his obd2 scan tool and my idle was reading higher than the gauge. We drove it around with it still hooked up and compared both readings and the scanner was reading double the tach.

Okay well that eliminates the ECU

 

[dsmornothing]

is it a good scan tool? not a 2-300$ one?

 

[Ghost_GSX]

Its a Craftsman OBD2 scan tool. I took the time to adjust the idle by sound and its sitting on the bottom line (500) and it sounds better at idle.

 

[Ghost_GSX]

Anyone else wanna have a crack at it?