Okay, I have a 91 crx dx gutted with si motor in it. I hook up a stock cluster, and the tach works fine. I bought a autometer 5 in tach, and when it gets to about 5500 rpm or so, the tach needle bounces all over.

I hooked up this tach to my 90 crx dx, stock, and it works just fine, no bounce at any rpm, and I hooked it up to the same wires, ground, 12 volt, as on the other car. This tach also works on my friends DSM. What the hell could be making this tach bounce around at 5000 rpm or so. Autometer was no help whatsoever.
He said get a clean 12 volt, good ground, and as close to the distributor as i could. I went right to the battery even, and right at the distributor, same issue as when it was in the car from dash tach signal.

???

 

bump

 

ur dizzy maybe?

 

If i understand this correctly? It only does this in the current car. first thing i would check is your plug wires sometime at high rpms the spark can find a weak spot in the insulation and cause an arch. when this happens your tach will bounce or jump cause of ground spike. This may not be your problem but, i have deal with this in the past. nevertheless it's a place to start. YOu may know how to check this but in case someone else don't . the best way i'v found is to wait till it's dark and have someone rev the motor and spray a fine mist of water from a water bottle around the plug wires if there's an arch you'll see it for sure. hope this helped........

 

ignitor is going bad

 

Okay, so the ignitor, the distributor, or the plug wires shorting out. My next question is, Why does the crx tach work just fine, but the aftermarket autometer tach go crazy then, if the ignitor, distributor, or plug wires are bad?

 

Do you guys know if the ignitor is the same from the crx dx to the crx si? any part numbers?