i have a 91 rs. the tach was reading high. common easy fix rite? i am in the middle of a complete restoration so i have a ton going on. being completly overwhelmed with my ebl i have been looking for somewhere to send the tach. Well i found a guy in the callified section that can fix it for 40 pluss 10 to ship it back. It cost 20 to shipo i gave him 20 to ship it back dispite what he said. Great guy fast turnarround but... there always has to be a but... with me. now the damn thing reads low. He said he double checked it on the bench and then put it in his car and it worked fine. So anyone out there have any sugestions? This drives me nuts.
Could it be my car or could it be he installed the wrong rester or something simple like that. I am getting a good reading out of my EBL could it be at the dash? I am so busy and i am so sick of paying for something only not to have it work like i paid for. I am tired of not being able to get anything rite.

 

Check your wiring. Are running stock distributor? Maybe the module in the distributor is bad? I had same issue with mine same car and year 1991. Cost me $175 though and the tachs reads fine. Got a dwell/tach? Get a known working tach for test purposes and see what is really going on is one suggestion. I am sure others have some good input also. FYI been told the GM tachs for 91-92 pretty much lousy from day one for accuracy.Good Luck.

 

He has a EBL so he is seeing exactly what revs the computer is seeing ( from a different source to the tacho ) for comparision

 

Hello, I repair tach chips also. But I only charge $35 including return shipping. On some of my repairs, I will solder a 250Kohm potentiometer allowing you to fine tune the calibration if needed. I can do this to yours if you are interested.

thanks, Greg