Foghead (aka - Chris) here...

I have a second gen rx7 (1983 variety) with a gas gauge that never reaches the 'full' line when the tank is topped off. Previous owner swapped float assemblies and instrument clusters without success. Highest that it goes is about 3/4 tank with it hitting empty long before running out of fuel.

Any pointers as to where I should be looking for known issues in this area?

 

1983 is 1st gen.
It sounds like the rod arm that holds the float is bent and causing a bad reading.That would explain the 3/4 full and Empty before actually empty readings.

 

Gen concept clarified. Ty.

But the whole unit was replaced with a new one.... Looks like it'll be a winter project...

 

Actually you can get to it from the side. By the back side of the driver's wheel well, there is a black plastic cover. Take the 10mm bolts off, remove cover and you should be able to see the sending unit. Unplug the sending unit, remove screws (possibly with a stubby phillips screwdriver) and pull it out. Might have to turn the sending unit slowly to get it out. 1/2 hour job tops!!!!!!!!!!!!!!

 

That may be so,but when you put the sending unit in the tank you can hit the float and arm,and it can bend the arm.
It may even have hit the baffle and bent it up when the guy installed it.

 

Very cool... thank you!!! Worse comes to worse, I'll just loosen the straps and possibly just drop one 1/2 of the tank to give myself a little more clearance. I'll dig through the service manual to see if there's a spec for the resistance on the unit.

 

Does the guage, after a certain point drop suddenly to E? If so then the resistance wire inside the sending unit may be broken. You will have to replace the unit. You can check this when the unit is out with a multimeter. The procedure should be in the service manual.

 

No... it drops linearly unless going through a corner in which case, a little fuel slosh occurs. It's gotta be a bent arm... or at least it may be fixable by bending the arm...

 

Sigh... jst a quick reply to myself....

 

...in order to get my thread count up... lol!

 

i have a problem with my gas gauge, i have a 1990 vert 2nd gen and when i fill it up it reads but when i think i get to half a tank it just drops to empty, wonder if it would be the same thing or another issue, help