1969 Mach 1 Speedometer Problem
05-08-2015, 09:25 PM
#1
Thread Starter
Join Date: Nov 2010
Location: Washington
Posts: 3
1969 Mach 1 Speedometer Problem
Hello,
I own a 1969 Mach 1 “R” Code with an automatic and air conditioning. I’m having issues with my speedometer. I recently had to replace my aging cluster circuit board. The repair shop broke the clip holding the speedometer cable to the back of the speedometer gauge and installed a new cable. Prior to the new speedo cable being installed the speedometer gauge functioned properly. My first series of issues after the the new speedo cable was installed were as follows (comparing my GPS speed) to the gauge:
1. The speedo gauge needle would not move until I reached a speed around 15 – 20 mph. It would then jump up and gradually match actual speed.
2. If I maintained a steady speed around 50 mph or higher the needle would slowly increase to 90 mph and keep going.
3. When I stop the needle would not return to zero but remain at around 15 mph.
4. When I jiggled the cable from inside the engine compartment the needle would drop to zero.
I suspected a bad cable and returned to the repair shop. They replaced the cable with a new one which created a new series of issues:
1. The speedo gauge would not move until I reached 20 mph. Then it would begin to move upwards but never reaching or matching actual speed. Under 40 mph (gauge speed) the needle would always be lower than actual speed; e.g. gauge reads 20 mph and actual speed is 35 mph.
2. Maintaining a steady speed of 50 mph or more the needle would increase quickly to around 90 mph.
3. If I go over road bumps or railroad tracks the needle would bounce higher and lower and then steady itself after a few passes but never matching actual speed. This occurs more frequently at higher speeds. This was a new issue.
4. When I stopped the needle returns to zero.
The repair shop performed the following troubleshooting steps:
1. Replace the speedo head gauge – no improvement.
2. Removed the inner cable and greased it - no improvement.
3. Replace the plastic speedo gear at the transmission – no improvement.
4. Inspected the transmission out gear – appears to functioning properly.
Anybody have any ideas how to fix this?
Thanks,
Larry
I own a 1969 Mach 1 “R” Code with an automatic and air conditioning. I’m having issues with my speedometer. I recently had to replace my aging cluster circuit board. The repair shop broke the clip holding the speedometer cable to the back of the speedometer gauge and installed a new cable. Prior to the new speedo cable being installed the speedometer gauge functioned properly. My first series of issues after the the new speedo cable was installed were as follows (comparing my GPS speed) to the gauge:
1. The speedo gauge needle would not move until I reached a speed around 15 – 20 mph. It would then jump up and gradually match actual speed.
2. If I maintained a steady speed around 50 mph or higher the needle would slowly increase to 90 mph and keep going.
3. When I stop the needle would not return to zero but remain at around 15 mph.
4. When I jiggled the cable from inside the engine compartment the needle would drop to zero.
I suspected a bad cable and returned to the repair shop. They replaced the cable with a new one which created a new series of issues:
1. The speedo gauge would not move until I reached 20 mph. Then it would begin to move upwards but never reaching or matching actual speed. Under 40 mph (gauge speed) the needle would always be lower than actual speed; e.g. gauge reads 20 mph and actual speed is 35 mph.
2. Maintaining a steady speed of 50 mph or more the needle would increase quickly to around 90 mph.
3. If I go over road bumps or railroad tracks the needle would bounce higher and lower and then steady itself after a few passes but never matching actual speed. This occurs more frequently at higher speeds. This was a new issue.
4. When I stopped the needle returns to zero.
The repair shop performed the following troubleshooting steps:
1. Replace the speedo head gauge – no improvement.
2. Removed the inner cable and greased it - no improvement.
3. Replace the plastic speedo gear at the transmission – no improvement.
4. Inspected the transmission out gear – appears to functioning properly.
Anybody have any ideas how to fix this?
Thanks,
Larry
05-10-2015, 11:04 PM
#2
4th Gear Member
Join Date: Mar 2014
Location: Austin, Texas
Posts: 1,155
Welcome to the forum.
No idea on how to fix it, but I have an idea for how you could get help.....try posting in the Classics section. The New Member area is not intended as a troubleshooting forum and you won't get much assistance here.
No idea on how to fix it, but I have an idea for how you could get help.....try posting in the Classics section. The New Member area is not intended as a troubleshooting forum and you won't get much assistance here.
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