putting older speedo in fuel injected car

[solarmon]

I really HATE the moronic 85 mph spedometer in my 80 spider. .want to change it out to an older 140mph unit. but. .
the main problem I can see with putting an older speedo in an injected car would be that there is apparently some sort of speed sensor for the fuel injection inside that stupid 85 mph stock unit. .with a separate wire out of the speedo that goes into the injection computer. ..

it also seems that the cable housing end was changed in 79. .from a metal screw-on type to a push-on plastic one. .

have NO CLUE what happens if you run it without that wire to hook up to on an older speedo. but I suspect it could cause some problems

I suspect that the only two options to haveing that wire to hook up to ae the stock 85 unit, or a european speedo from an injected car. .which may or may not come in MPH

anybody had experience with this?

[lanciahf]

Find a 79 Speedo, same gauge depth and fittings. BTW 79 Speedos go up to 140 mph.

[Tobi]

I have a 120 mph speedo (year?) in my 1981and the cable hookup was different but for some reason it works.
I don't know what that wire is for but I did not notice a difference from that after changing 4 years ago.
Could it be that the wire is for that oxygen sensor in the exhaust that has to be replaced every 10,000 miles?

[launieg]

I replaced my 80 mph speedo in the FI '81 with a 160kph (Canada) from a '78. Have checked it against highway markers and it works perfect. So I can't see your swap being any problem.

[Sunracer]

The one you want is a 78 speedo, shallow dish like the rest of your instruments with a normal speed range. Also, it uses the clip on cable PB

[azruss]

the speedo is driven by a cable and isnt electronic. the older speedos have different idiot lights. that is what the wire is about.

[Danq]

tobi is right.
That wire does go to the lamba sensor timer/relay. It located above the accelerator pedal