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-   -   Smith's Reverse Speedo problem and most gauges.... (http://www.clubcobra.com/forums/shop-talk/115243-smiths-reverse-speedo-problem-most-gauges.html)

donnieR32 04-17-2012 01:19 AM
Smith's Reverse Speedo problem and most gauges....
 
I realized very quickly that my speedometer doesn't work...actually I think the only gauges that are accurate are the tach and fuel pressure.

Anyways, I attempted to use GPS from my phone which claimed it was pinging between 7 and 11 satellites and in 3rd gear I was about 6 mph faster (on the dash) than what the phone claimed. Is this an issue that I can fix or is this something that will have to be handled in a shop?

mickmate 04-17-2012 03:52 AM
Yes you can send them in and have them calibrated. I have found they prefer a measured rolling number to a GPS measurement. Shoot me an e-mail address for the instructions if you want them.

strictlypersonl 04-17-2012 05:30 AM
First do a measured mile and check the accuracy of the odometer. If that's off, the change should be done by replacing the driven gear on the transmission end of the cable.

elmariachi 04-17-2012 09:36 AM
Quote:
Originally Posted by strictlypersonl (Post 1186262)
First do a measured mile and check the accuracy of the odometer. If that's off, the change should be done by replacing the driven gear on the transmission end of the cable.
Great advice. Get the odometer synch'd first and then see what your speedo says using a high quality GPS. Too much latency in cell phone GPS technology.

donnieR32 04-17-2012 10:56 AM
Quote:
Originally Posted by elmariachi (Post 1186290)
Great advice. Get the odometer synch'd first and then see what your speedo says using a high quality GPS. Too much latency in cell phone GPS technology.
Seeing that I don't have a high quality GPS I wonder if it would be more cost effective to just send them in.

CHANMADD 04-17-2012 11:05 AM
Most factory speedos read a little fast , designed in to keep us at or under the legal limit.
I have an app. Speedview, on my phone which I have found to be extremely accurate.

elmariachi 04-17-2012 11:26 AM
Quote:
Originally Posted by donnieR32 (Post 1186298)
Seeing that I don't have a high quality GPS I wonder if it would be more cost effective to just send them in.
You can install a calibrated speedometer in a car with the wrong speedo gear and it will still be wrong.

donnieR32 04-17-2012 03:15 PM
Quote:
Originally Posted by elmariachi (Post 1186303)
You can install a calibrated speedometer in a car with the wrong speedo gear and it will still be wrong.
This is what I was thinking because it seems to be 6 mph faster in 3rd gear but like 9 mph faster in 4th....so maybe it is the speedo gear.

strictlypersonl 04-17-2012 03:17 PM
Quote:
Originally Posted by elmariachi (Post 1186303)
You can install a calibrated speedometer in a car with the wrong speedo gear and it will still be wrong.
Most highways around here have mile markers along the way. Sometimes they're subtle: Just a post with a number.

mickmate 04-17-2012 04:47 PM
I agree to check it against a measured mile first. Even with the supposedly correct gear they can only come close. One tooth higher or lower will account for the reading difference you are seeing. The calibration instructions were sent to your e-mail.

elmariachi 04-17-2012 07:20 PM
Quote:
Originally Posted by strictlypersonl (Post 1186323)
Sometimes they're subtle: Just a post with a number.
That's funny. :LOL:

donnieR32 04-17-2012 08:57 PM
Quote:
Originally Posted by CHANMADD (Post 1186300)
Most factory speedos read a little fast , designed in to keep us at or under the legal limit.
I have an app. Speedview, on my phone which I have found to be extremely accurate.
Is this serious? Why would anyone intentionally make a measuring instrument incorrect :JEKYLHYDE If I buy something I want it to tell me exactly what its meant to tell me. That's like buying a phone that hangs up mid-call to save you money.

I think I was using Speedview as well...I can't remember.

elmariachi 04-17-2012 09:19 PM
Quote:
Originally Posted by donnieR32 (Post 1186372)
Is this serious? Why would anyone intentionally make a measuring instrument incorrect :JEKYLHYDE If I buy something I want it to tell me exactly what its meant to tell me. That's like buying a phone that hangs up mid-call to save you money.
He might be serious but its not true. There is no underground collusion of forces trying to make sure all speedometers read wrong to slow us down. We might be headed in that direction, but I don't think we are there quite yet.:rolleyes:

DougD 04-22-2012 01:01 PM
Quote:
Originally Posted by strictlypersonl (Post 1186323)
Most highways around here have mile markers along the way. Sometimes they're subtle: Just a post with a number.
Don't assume that highway mile markers are placed at intervals of exactly one mile. Ever wonder what happens to the existing mile markers when the roadway is reconstructed, resulting in a longer or shorter route? Here's a hint - they don't dig up all the mile markers after the revised portion of the road and replace them. Take it from someone who has 35 years of road construction experience - the mile markers are not all a mile apart. They were never intended to be a precise measurement.

vatdevil 04-22-2012 05:24 PM
Remove the speedo cable from the trans and count the teeth on the driven gear. Try the next tooth count available. Not sure what trans you have but a Tremec replacement driven gear is around $20. Just replaced mine due to tire size change, very easy to do.

donnieR32 04-22-2012 05:34 PM
Quote:
Originally Posted by vatdevil (Post 1187100)
Remove the speedo cable from the trans and count the teeth on the driven gear. Try the next tooth count available. Not sure what trans you have but a Tremec replacement driven gear is around $20. Just replaced mine due to tire size change, very easy to do.
Are these gears easily obtained at local automotive stores or will I have to order them online?

ETA:
To answer your question the trans is a Ford Toploader 4 Speed

elmariachi 04-23-2012 06:57 AM
Your local Ford dealer likely has a few of them (that's where I found mine for my TKO), if you can engage a knowledgeable parts counter person. Some reference here:

Ford Speedometer Gears for Automatic and Standard Transmission

vatdevil 04-24-2012 05:38 AM
Fortes Parts can supply.


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