I have a 79 RX7 with sixty K miles on it and have posted here before but it's been a few years with it sitting in the garage ( Heated) It was difficult to start and we established three days back that the fuel pump was working part of the time but was erratic. So, sometimes it would start, run for a while and then die. We replaced the fuel pump and it now works fine. We replaced the filter as well. . So it runs. I am replacing the tires since the old ones are cracked and unreliable and when the rear left wheel ii off, I would like to pull the fuel sender which does move, but not much. I understand it is accessible behind the wheel and we don't see it. Was I wrong in my understanding of the location. I saw one person saying the gas tank had to come out, or at least down and another saying it could be approached with out that PIA. Once I have it out, I read one person saying they simply soaked it in a cleaner and another saying it might just be a bad ground. We can try the ground first but wanted more opinions about it. I do understand the sender is no longer made and was wondering if a sender from a later model might be available and fit? It's overall a very nice machine, garaged for 40 years always heated. If I ever gain any fundamental web/photo skills, I'll try to post a picture of it. Thanks in advance.

 

The sender can be accessed by removing a plastic (might be metal on a 79) cover just behind the rear wheel. It is there to keep debris from hitting the sender and fuel filler etc. The bolts can be a pain to get undone but some heat and PB blaster usually will do the trick. No need to drop the tank. The sender has a gasket that may need to be replaced if you remove it. Usually the sender has a poor ground connection that causes it to not read full when the tank is full. Before removing the sender clean its connector really good and see if that works better. Another way to get a better ground is to add a wire from the core of the send unit (its at the center of the top of the sender) to one of the sender bolts holding it in. I had to do this on my 80 to fix the sender ground. Note that the bolts holding the sender in usually break or get trashed on removal, so be prepared to R&R with new bolts of the right thread and size. Good luck! Its annoying for the sender to be in error but will not affect running at all.

 

Do this google search and read thru the threads. We have all been there.

sender ground site:https://www.rx7club.com/1st-generati...-1979-1985-18/

 

We shall dig in on Monday. I have a few other issues but not a lot. I will come back on vacuum leaks which sound like I'm not the first to have them.

Thank You!

 

Dropping the tank really isn't a big deal. It gives you a chance to replace the soft fuel lines and inspect the tank.

 

virtually every rubber line was cracked, or cracked once we touched it, so that is done, all the way to the front. Monday, I'll get back under it with the man who is doing most of the work. I'm just too old and too stiff to do much. Getting in is hard enough. Getting out may be worse. .

 

I replaced the linear rheostat in the fuel gauge sender unit with one salvaged from a newer one. The overall size and connections were the same, and it looked like the same number of windings, but there is a slight difference in the 'front face' of it (diagonal ridge vs straight across).
https://www.rx7club.com/1st-generation-specific-1979-1985-18/fuel-level-sensor-sender-out-gas-sensor-1171192/?utm_source=share-link&utm_medium=button&utm_campaign=share&utm_cont ent=post

It was a partial success. The gauge hangs around full for a while, then it drops to half-full, then work its way back up, wandering between the two, then it sort of settles down for the drain down to 'empty'. But the "outta gas" light works! Can I call this a partial success?

 

That's yet another possibility. I don't have an "Outta Gas" light sadly. I know it when it happens though. How can the electric clock still work at this point is a mystery to me.

 

The electric clock is unstoppable unless your battery runs completely down!

 

So, time flows by. I finally got four new tires for the car and had intended to go after the fuel sender unit which I had thought was behind the left rear wheel. Currently the wheels are off all around only there was no cover plate for the sender behind the left rear to be found- nothing! Were there variations on where to hide the thing on the '79 car. I'm down to so little to fix on the car. The vacuum leaks and bleeding the brakes are the others remaining but given the size of the fuel tank and the terrible milage these things get, having the fuel gauge would be nice. Should I just bite the bullet and drop the fuel tank and look elsewhere? We replaced all the soft hoses for the fuel.

 

The cover is inside the rear wheel well and forms part of the inner wheel well protection. Its not an exterior cover that you can see. If you have the wheels off, just go to the driver rear and look behind that wheel and you will see that the back part of the wheel well if a separate piece that comes off with the removal of a few nuts. Take a look at this thread for some pics of what I mean: https://www.rx7club.com/1st-generati...cement-353758/

 

The cover / plate he refers to is right here. It has 3 points of attachment.