Is this normal? Tach/spedo
Team Owner
Joined: Sep 2003
Posts: 25,422
Likes: 2,750
With the KEY-ON engine NOT running does the tach park @ 0? If it doesn't then I'm quite sure you've a calibration issue. If the car is a C68 ATC you can get the RPM that the ECM sees by using the diagnostics in the C68 control. I'd get a scanner on it to confirm if you could.
Without actual tire dimensions it's impossible to tell you what to expect for RPM at any MPH and actually with the tire/wheel swap it's certainly not correct on the speedometer UNLESS it's been corrected for the change.
Have you ever compared the speedo/odo to a GPS for validation or error?
Without actual tire dimensions it's impossible to tell you what to expect for RPM at any MPH and actually with the tire/wheel swap it's certainly not correct on the speedometer UNLESS it's been corrected for the change.
Have you ever compared the speedo/odo to a GPS for validation or error?
Last edited by WVZR-1; Sep 13, 2017 at 12:06 PM.
Thread Starter
Instructor
Joined: Aug 2015
Posts: 225
Likes: 30
Spedo
Im pretty sure the speed is correct, i have done the gps thing and im within 1.5 mph at 60 mph. I am at zero with key on but at idle im well over 1k but under 2k and it idles normal. Just blows my mind that its in redline and im definitely not revving that high. I know WELL what 5500 rpm feels like. I appreciate the response, ill check the c68. Im familiar with using it. My temp gage dont work either lol.
Burning Brakes
Joined: Mar 2010
Posts: 1,094
Likes: 68
From: Providence RI
90 and 91 clusters are prone for being brutal.
My tach reads off by 200 rpms at idle, reads 2400 rmps at 2000, etc. I've verified with TTS and the HVAC method.
My oil temp gauge doesn't work, but works on TTS. IT shows some movement as it gets hot but is way off. Oil pressure is pretty accurate as well as coolant temp and volt meter. Just remember those gauges are not linear...
I am looking to get mine rebuilt. Not sure where yet.
My tach reads off by 200 rpms at idle, reads 2400 rmps at 2000, etc. I've verified with TTS and the HVAC method.
My oil temp gauge doesn't work, but works on TTS. IT shows some movement as it gets hot but is way off. Oil pressure is pretty accurate as well as coolant temp and volt meter. Just remember those gauges are not linear...
I am looking to get mine rebuilt. Not sure where yet.
