just go the 7 a couple weeks ago, previous owner wired the sender so it always reads full. found a used 79 and a beat up 82 sender. this is my first 7 so i don't know whats all compatible between the years yet. the 82 is in pieces and the 79 has some build up or something on it that scrapes off easy. i tried all the auto parts stores around but they didn't have anything and from what i read i'll have to pay like $100 to get one from mazda. this is just my beater to get me around while i work on my bug and i'm not trying to spend alot of money on it. i'm not real worried about driving without one cause i just keep a gallon gas can behind the passenger seat but if i can get the 79 for cheap and its compatible i'll throw it in and hope it works. its also leaking oil pretty bad from what looks like the seal around the front of the case. looks like a motor pull to fix and like i said its just my beater so i just keep adding oil. thanks for the help.

 

The '79 sender isn't *directly* compatible, but I'm pretty sure you can make it work.

Y'see the '79-80 models have a *huge* number of differences from the 81-85 models. They redesigned or changed something in pretty much every major system of the car.

What this means to you is that the fuel sender in your '82 has 3 prongs on it, and the '79 has only two. Get yourself a Heynes manual, believe me it's the best $20 you'll ever spend!

I would just get the heynes and see if you can re-wire the old fuel level sender to work properly. If that doesn't work, match the two prongs on the '79 to the wires on the car (you'll probably have to cut the connector off and solder or tie them there). If you do it with the sender in your hand, you can have someone sit in the car and check if the guage changes when you move the '79 sender arm.

In the Heynes manual, the '79-80 fuel sender pinout is in the electronics chapter, while the later model sender is in chapter 13 "revisions". I'd quote the pages so you can find it but my Heynes is at home.

So try fixing yours, and if not, test the '79 out of the tank before mounting it. If that doesn't work.. Well then you'll either have to find another used one or do what I did - I bought a new one from www.mazdatrix.com for a hundred bucks

Jon

PS: Trust me, buy the Heynes.


Edit: found it! Page 304 of the Heynes shows the three-pronged one (if the one on your car turns out to be three pronged.. .might only be 84-85 in which case you're fine for the swap).

If you don't have the heynes, here's a thread with a crappy MSPaint version of the three-pronged plug's associated wires:
https://www.rx7club.com/showthread.p...hreadid=282986