I recieved a nice 140mph speedometer from my friend I installed into my iroc. its the one with no kph, and has z28 logo printed in the bottom. trip meter reset at the nine oclock position. trip meter above the odometer.
it looked like the hole the speedo cable snaps into was further recessed then my stock 89 speedometer was. after installation TWICE, my speedometer does not work, i believe my cable is not entering the speedo far enough to engage the square hole it locks into.
i have verified my cable still spins while driving forward. and before i installed my gauge i could spin the back of it by hand and the needle would move, and it was verified to work when it was removed 3-4 years ago, just sat in his garage till i nabbed it.
so did these aftermarket dealer installed gauges use a different speedo cable?
it looked like the hole the speedo cable snaps into was further recessed then my stock 89 speedometer was. after installation TWICE, my speedometer does not work, i believe my cable is not entering the speedo far enough to engage the square hole it locks into.
i have verified my cable still spins while driving forward. and before i installed my gauge i could spin the back of it by hand and the needle would move, and it was verified to work when it was removed 3-4 years ago, just sat in his garage till i nabbed it.
so did these aftermarket dealer installed gauges use a different speedo cable?
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Quote:
That's an 85/86 speedo and it not compatible with your '89. You can get a cable to fit, but it's missing the speed sensor for the ECM.Originally Posted by TraviZ
I recieved a nice 140mph speedometer from my friend I installed into my iroc. its the one with no kph, and has z28 logo printed in the bottom. trip meter reset at the nine oclock position. trip 
JamesC
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Apr 15, 2026
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With OE speedos there should be no issue with cables. I have an OE 145 in my 85 IROC, single cable.Originally Posted by jv9999
That's an 85/86 speedo and it not compatible with your '89. You can get a cable to fit, but it's missing the speed sensor for the ECM. As I understand it, there are three types of speedo cables: a two-piece design used with a transducer (in the early years), then a two-piece that apparently screwed together or joined in some manner, and finally a single piece. None of the above were equipped with a speed sensor. The VSS is installed on the rear of the cluster, 82-89.
IIRC, you can buy the cable itself and cut it to the size you require, say a 1/4 longer. I assume you could use the same housing. Also, is it possible that end of the cable simply isn't finding its way into the speedo and seating properly (don't ask me why I suggest that)?
JamesC
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As I understand it, there are three types of speedo cables: a two-piece design used with a transducer (in the early years), then a two-piece that apparently screwed together or joined in some manner, and finally a single piece. None of the above were equipped with a speed sensor. The VSS is installed on the rear of the cluster, 82-89.
IIRC, you can buy the cable itself and cut it to the size you require, say a 1/4 longer. I assume you could use the same housing. Also, is it possible that end of the cable simply isn't finding its way into the speedo and seating properly (don't ask me why I suggest that)?
JamesC
But the VSS mounted on the back of the cluster used an optical sensor installed on the back of the speedo. I don't think the earlier ones had the mounting for it (but I could be wrong). I think you're right about the cables though. They should all be the same.Originally Posted by JamesC
With OE speedos there should be no issue with cables. I have an OE 145 in my 85 IROC, single cable.As I understand it, there are three types of speedo cables: a two-piece design used with a transducer (in the early years), then a two-piece that apparently screwed together or joined in some manner, and finally a single piece. None of the above were equipped with a speed sensor. The VSS is installed on the rear of the cluster, 82-89.
IIRC, you can buy the cable itself and cut it to the size you require, say a 1/4 longer. I assume you could use the same housing. Also, is it possible that end of the cable simply isn't finding its way into the speedo and seating properly (don't ask me why I suggest that)?
JamesC
JamesC
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Apr 15, 2026
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I've never seen an 82-89 model without the VSS mounted on the rear of the cluster--of course, I haven't seen them all. I've also never heard mention that it was cause for problems in swapping speedos.Originally Posted by jv9999
But the VSS mounted on the back of the cluster used an optical sensor installed on the back of the speedo. I don't think the earlier ones had the mounting for it (but I could be wrong). JamesC
Quote:
i dont have a ecm anymore, i dont care about vss.Originally Posted by jv9999
That's an 85/86 speedo and it not compatible with your '89. You can get a cable to fit, but it's missing the speed sensor for the ECM. so no one has heard of different speedo cables? I wonder why mine isnt working then. maybe i should bust out some photos of my problem.