The guy’s got a call today from a woman in Minneapolis saying the transmission on her Honda wasn’t shifting right. She also noted that when this occurs that her tachometer was acting erratically.
One thing that can cause this is the distributor signal module. This is mounted at the base of the ditributor. And what this module does is sends a signal to both the tachometer and the engine management computer. From this the computer determines the shift points from the signals it recieves from this module and from the Vehicle Speed Sensor. If the tachometer is recieving erratic signals so too is the engine management computer. When this happens the engine manegement system becomes confused with signals it’s recieving from this module along with the signals from the Vehicle Speed Sensor. This then causes the transmission to shift incorrectly.
I suggest this because I’ve replace numorous distributor signal modules on Honda’s for this exact same problem.
Tester
I have this exact issue on my '89 Accord. I went to hondaautomotiveparts.com and found a part on the distributor diagram labeled “CONTROL ASSY., VACUUM” which is mounted on the bottom of the distributor and is round in shape. It costs $52, does that sound like the correct part?