1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

speedometer issues, help!

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Old 05-16-06 | 01:57 PM
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edwin-82/rx7's Avatar
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speedometer issues, help!

Installed my '83 speedometer cluster last night, now my speedometer is roughly 7mph slow. is there any way that i turned the speedometer cable while putting it in? The center is a square pin, i'm thinking it could have rotated too much one way and its throwing things off. is this possible or not?

btw is was so easy to take out... if you remove the heater tube that runs under the steering column. you can get to the speedo cable by laying on the floor under the dash, its very easy.

i tried turning it as much as i could before plugging it in, but that hasn't helped.


*edit* is there any other way to calibrate the speedo without pulling the dial and putting it back on?

tia
Old 05-16-06 | 02:02 PM
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...my understanding is that the speedometer cable rotates already, so rotating the cable by a half turn(or full turn, or 189 turns) is not going to make any difference...

...how are you measuring the difference in speed? its possible your previous speedo was off and this one is right....
Old 05-16-06 | 02:13 PM
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with my gearing, 3k in 5th is 60, 4k in 5th is 80, 5k is 100... and i made quite a few runs at the speed thing that the cops set up with the old speedo :-)

also, the needle stays on the bottom pin for a while when accelerating in 1st.

from the back of the speedo, i tried rotating the cable assbly clockwise before plugging it in. my thinking was that if it needed to move the needle sooner, rotating the square pin 90 deg. would work, putting more tension on the cable before it started turning.

i operate primarily on fuzzy logic!

j
Old 05-16-06 | 03:37 PM
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i would get the speedometer gear from an 83 trans that would turn at the rate that the 83 speedo would.
Old 05-16-06 | 03:46 PM
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the amount that its off appears to be linear. i really don't want to be switching speedo gears around...

what about holding the pin up while i put the cable in?
Old 05-16-06 | 05:02 PM
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your cable has nothing to do with it. the gear turns heh cable at a certain rotation rate and its matched with the gear in the speedometer part of the cluster.
Old 06-06-06 | 02:36 PM
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im bumping this cuz im having somewat of the same problem.. i cant find the thread i was reasding earlier to post it on there so this will have to do.

my speedo pins when i accelerate and it stays there. all the time. so i thought it was the cable and replaced it... 20$ and a half hour later i realize that isnt the issue...... so what is? the speedo gear? and if so where can i get one?
Old 06-06-06 | 03:02 PM
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Originally Posted by edwin-82/rx7

also, the needle stays on the bottom pin for a while when accelerating in 1st.
This is your clue right here. Either the cable is binding a bit in it's sheath, needing cleaned and lubed, or the dial/needle needs reset.
Old 06-06-06 | 10:28 PM
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well i got a brand new cable and i lubed it up, so its not binding ant all and theres no kinks and tight turns in my setup. so its not the cable... how do i reset the dial\needle? and can i do it without taking of my dash?
Old 06-06-06 | 11:13 PM
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bump
Old 06-06-06 | 11:20 PM
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Did you get a brand brand new cable and sheath or a used one and what did you lube it with? If it was a used cable or sheath, it needs cleaning before lubing. If both were band new, it should not have been lubed. What did use use for lube?

If the needle pegs and stays, I may be the head unit is bad. Check that the needle is not bent and catching on the face of the dial, before replacing the speedo itself.
Old 06-06-06 | 11:25 PM
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it was a new cable and new sheath. and i used the lube that came with the package. the need isnt bent at all. it just goes to 85 and stays there (which is top end on my speedo hahaha) so i dont know wat to do...
Old 06-06-06 | 11:35 PM
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Change to the other head unit, or quit going over 85.
Old 06-06-06 | 11:51 PM
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quit going over 85... hahahaha
i have no idea wat u mean by switching to the other head unit.
Old 06-07-06 | 12:29 AM
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Sounds to me like someone removed the needle on your new cluster and didn't put it back on in the right spot. I removed the needle on my previous cluster and never got it back on right. its a real PITA as my speedo was off by about 10 mph all the time.
Old 06-07-06 | 12:36 AM
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nope.. cluster has never been removed... wat exactly happened was this


car worked great, no problems...
i left for cali, came back a week later...
speedo shot to 85 (pinned) and stays there till i slow to a stop, then it goes back to 0..

i replaced the cable, and it does the same thing, just shoots to 85 a lil bit slower..
Old 06-07-06 | 12:46 AM
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ild sugest takin it out cleaning contacts have a basic look at the circuit to see if theres corrosion or maybe a lose track
Old 06-07-06 | 01:16 AM
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From: St Joe MO
Replace the speedometer.
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