wierd problem
 

okay, on my fd i had this weird thing happen, my odometer, stopped displaying the milage when *cold weather* came. so now i drive the car and it dosent record milage:D which is cool, but its a pain the the ass eveytime it gets servied anywhere or if i want to sell it, when its hot outside the odometer kicks back on and the add coolant light comes on as well. I check the coolant and its fine, i had the coolant sensor checked and it was in working order as well. anyone else have a problem like this or any solutions, thanks

not sure, my gauges act up sometimes as well.. My speedo will just jump from 70 up to like 95 or 100 while i'm at a steady speed. If i speed up to 90 or so it will read like 130! when i come to a stop it falls back to zero. The increased MPH is probable adding more miles to my car than i'm actually going... Not that it helps you but maybe out problems are related.

got to be an electrical problem...I would suggest taking it to a authorized rx7 specialist and having them look at it if it is a big deal to you

You have an electrical problem, as the speedometer is electrically controlled in an FD. This will not affect the accuracy of your odometer.

I dont' know if the speedo is controlled through the ECU at all, but if it is, try another ECU. If your problems is fixed, you know your ECU is bad for some reason.

in the service manual it shows a speed sensor on the top side of the tranny.. maybe it was damaged during a recent clutch install. i'll have to check it sometime.. The problem is kinda rare and i can tell my speed by my RPM's (close anyhow) so i'm not in a big hurry. Thanks guys.

Check the wiring harnesses. Did you disconnect anything lately. Sometimes moister can find its way into harness connects and cause them to short and also causes them to expand and contract. I've had problems from getting Armor All down in steering column and in the dash on my previous car that caused some temporary electrical problems.

If all else fails.
 

FD dashboards are prone to "cold solder joints" this is when the circuit board components become loose where they are supposed to be soldered. I don't have a pic but if you look at the circuit board and move things you will see a small crack appear around the solder point. They are very temperature dependant as well as shock and vibration. If you have any guage jumping or on/off/on behavior first rule out the sender if its easier and you only have one symptom. If you have multiple things take out the cluster and inspect or better yet, use a small solder pencil and remelt all the solder points applying new solder where needed. IMHO.:)