[ks gto (Cap)]

I realize the 64 takes a different sending unit than the 65. As I understand it, the diffence is the ohms for the two years'.
I have purchased an original 64 sending unit. It has "90 OHMS" stamped on the side of the "case" the float arm goes into. I'm assuming that's the ohms of the 64 sending units
My question is; Is the 65 sending unit stamped with the ohms pertinent for the 65 model year? And what are the ohms for the 65?
Thanks in advance. Cap

[Peter Serio]

All 1963 Tempest-Lemans and 64 Lemans/GTO dash gauges operate off of a range of from: zero to 30 ohms. In 1965 for Tempest-Lemans including GTO they changed the design of the dash gauge so that the sender now gives a range of from between zero to 90 ohms.

[ks gto (Cap)]

Pete----what you're telling me is, that it's the gauge that's the key? That a 64 gauge (0-30 ohms) has to have a fuel sending unit that operates from 0-30 ohms, but if the gauge is a 0-30 ohm gauge it won't read correctly with a 65 sending unit?

[veet66]

Peter is correct. I just got through going with a sending unit problem on my 65. If you have a 64 and your gas gauge is a 64 gauge and has not be changed to a 65 gauge you have to use a 0-30 ohms sending unit. On a 65 gauge you have to use a 0-90 ohms sending unit. Some of the sending units on the side of the float will read 30 ohms or 90 ohms.
I have bought 2 sending units in the past 2 weeks for my 65. The first one I bought it was for a 65 but there were no ohms on the side of the sending unit. I used my ohms meter before I put it in the tank and found it was a 30 ohms. I contacted the distributor and told him the problem and he said it must have been a defect. On the second one I bought from another vendor. Still no ohms on the side of the sending unit so I also checked it with an ohms meter. It was a 90 ohms unit. So check it before you install it.
I still am having a problem with the gauge. The old sending unit megged out at 106 ohms. The tank gauge shows full when the gas tank is full of gas. With the 90 ohms unit my gas gauge reads just below full when the tank is full. I checked the gauge before I installed it in the full position and the gas gauge showed full. I believe my problem is the float is hitting the top of the tank not letting the float to go all the way up to the full position on the sending unit.

[ks gto (Cap)]

Thanks guys for the help----btw veet66....the original sending unit I bought is stamped "90 ohms" on the case, but as I checked it with a multi meter, it measures 30 ohms. So relying on what's stamped on the side could lead you astray--just an FYI. Cap

[veet66]

Yes sir, I have decided anything I can check before I put it in I do so. In the fuel sending unit case what a pain it would have been if we just installed the unit and fill the tank with gas. Then have to empty the gas to take it back out.

[Peter Serio]

You have to match the design of the gauge to the sender. They operate as a matched set. Either zero-to-30 or zero-to-90. If you study the face of any '64 fuel gauge vs. a 65 gauge ( we are talking standard dash-here) you will see there is actually a slight difference in the arch of the lined artwork and the shape of the dial. The gauges are very different in construction.

I tend to think the '65 and up gauges are an imporvement over the 64 type. But either one will work fine as long as it works and you have a clean sender to match it.


I ALWAYS test electrical parts; new or NOS, before I install them!!! It can save you a lot of time if you can catch a bad part before you go thru all the trouble to put it on your car!