Bye-Bye Malaise Era Speedometer

[Wolfman2332]

Thanks focodave. I have found a company that restores old instruments, and am considering sending them there to get the font match. I will be looking at the next week when I drop by Giovanni's. Have a few scratch on the speedo, but I think a quick coat of flat black will do the trick.

The car looks fantastic with the old bumpers on it, new tires and slightly wider stance. I am really looking forward to driving this summer!

[Wolfman2332]

Well, there are no 140 mph speedos from that era. I got one, and Giovanni says it will not fit. I am sniffing around for a kph to have refaced to mph. Found guys that will do it, just have to get it and do it. This is the last of the erasure of the 'Carter Malias' era mods the gov forced on us.

The 5 mph bumper really torques me down - had a minor 2 mph accident and need to replace you bumper with all the sensors? Try K plus!

[Wolfman2332]

Searched high and low for a non-malaise speedo for my 84. BAYLESS found one for me, and it improved the looks and fun. Bayless did a great job!

For milage, I left it alone. Mine had 14,500 on it, and the new one 17,000. I can live with that.

[Lstdnsr]

Looking to do the switch to the 140 mph speedo in my 1981 spider 2000 FI. Was all set up to switch them as its time to put the dash in and drive this car. However there appears to be an extra wire coming out of the back of the original speedo and it disappears into one of the wire bundles. It does not go into a bus. Back of speedo has a little plastic plate retained with a screw behind which the wire goes. When I removed the dash it had been twisted together and taped by PO. I put connectors on it to reconnect. It is orange with red stripe and I dont know what to do with it or what it does or if the fuel injection has something to do with it. Cant seem to find it in the wiring diagram. But the 140 has no wire or access plate. Also, does the140 mph speedo need a different sender on the trans or is the gearing the same?Any ideas? Help would be greatly appreciated.
Thanks
Tim

[focodave]

Looking to do the switch to the 140 mph speedo in my 1981 spider 2000 FI. Was all set up to switch them as its time to put the dash in and drive this car. However there appears to be an extra wire coming out of the back of the original speedo and it disappears into one of the wire bundles. It does not go into a bus. Back of speedo has a little plastic plate retained with a screw behind which the wire goes. When I removed the dash it had been twisted together and taped by PO. I put connectors on it to reconnect. It is orange with red stripe and I dont know what to do with it or what it does or if the fuel injection has something to do with it. Cant seem to find it in the wiring diagram. But the 140 has no wire or access plate. Also, does the140 mph speedo need a different sender on the trans or is the gearing the same?Any ideas? Help would be greatly appreciated.
Thanks
Tim

Hello Tim,

That wire, with the red stripe, you are referring to feeds a mileage signal from the speedo to the oxygen sensor switch box, which in turn will illuminate the oxygen sensor warning light in the middle of your dash when it is time to either inspect or replace the oxygen sensor. That was sort of an old fashioned version of today's "check engine" light.
You can simply tape off that wire and forget about it, unless local laws prevent you from doing that.
By taping off the wire, the oxygen sensor light in the middle of the dash will never illuminate.

As far as gearing goes, it is most likely that you will not need to change the speedometer drive gear in your transmission.
It is highly probable (but not guaranteed) that your car and the donor car both have a 3.90 rear differential gear ratio and that the donor car speedo will give the correct readings in your car.
At least that is what I experienced with my speedo swap.

Kind regards,
Dave

[Lstdnsr]

Thank you Greatly. One step closer to the road. Does the O2 sensor give feedback to the ECU? Or just an emissions thing. I am no longer tested or inspected in NJ based on age of car, but want it to run right. Sensor appears to be new(er), does it warrant replacement?
Thanks
Tim

[focodave]

Thank you Greatly. One step closer to the road. Does the O2 sensor give feedback to the ECU? Or just an emissions thing. I am no longer tested or inspected in NJ based on age of car, but want it to run right. Sensor appears to be new(er), does it warrant replacement?
Thanks
Tim

Yes, the O2 sensor provides feedback to the ECU to adjust air-to-fuel- ratio.
Disabling the warning light with your new 140mph speedo will not negatively affect the operation of the O2 sensor, ECU, or FI system in general.
The switch box that takes the mileage signal from the speedo is set to turn the warning light on after it detects 30,000 miles have occurred since the last reset.
The switchbox can be reset by breaking the wire seal and pushing the reset button.
It is impossible for me to say if your O2 sensor warrants replacement without being able to lay hands on your car and without being able to test a bunch of things.
If the sensor is relatively new, was not fouled by greasy mechanics' hands during installation, and your car is not burning large amounts of oil and laying down a blue smokescreen when you drive it -- the sensor should be fine. They are surprisingly durable when they are treated correctly.