Hello. I have a problem with the tachometer display.
At idle rev limiter occurred at 4k rpm, but running at 4.5K rpm. The same engine torque in to 6.5K rpm, but rev counter shows as 4.5K rpm. A replaced the same tachometer dial and ignition control module, but nothing changes.
Where else could be the problem? Engine is D15B7.

 

Where are you getting this information from?

 

From my tachometer display.

 

Where are you getting this "The same engine torque" information? How do you know you were at 6.5k rpm if the tach only showed you 4.5k rpms? And the tach doesn't show torque (and I don't know anything that does). Do you have some crazy 2-step programmed into this?

 

Could be assumption based on the P06 on the D15B7 having a rev limiter at 6.5K RPM. So basing it off of hitting limiter while tach shows only 4.5K.

Just guessing this is what OP is doing and assuming.

 

Add an external tach by running the wire directly to distributor.

 

I agree with grumble. I can't make any sense out of the first post.