Gas gauge 74 Duster help
No Sorry "it is not fine." It is, or was, a well known fact on here that "all" the repop senders are inaccurate. Part of the problem is that they don't follow the same resistance THROUGH THE RANGE as the original OEM, and part of the problem seems to be that the mechanical movement is simply not the same.
I didn't say it would fine. I said if the resistance is where it is supposed to be, it should be fine. Yes,... the site only tells you what it is supposed to be at full and empty, and yes, the resistance is not linear between full and empty. Gauge midpoint should be about 23-25 ohms.
If he can't find one anywhere else, he could get one from there and test the resistance through the range, or at least at full, mid, and empty to see if it's going to work. If the resistance doesn't match up,..... send it back before installing to get his money back.
80 ohms should just barely move the needle, if at all. I used 2 150ohm resistors wired in parallel to give me 73.8ohms. On my gauges, that JUST barely moved the needle. 23-25 ohms should put the needle in the middle position, and 10 ohms should put at, or slightly above the full line. I haven't tried to calibrate the gauges in a '74, but in my 68-70 B Body rallye dash, there are two windows on the back of the gauges that allow you to adjust the needle position at the top and bottom of their range. You calibrate by putting known 5 volts to the gauge with different resistors between the other post and ground source. I check the midpoint, but don't care if the needle is exactly accurate in that middle range. I need to know where it is running in relation to "Normal"
I never insinuated that it was going to be just a "Drop-in" and it's going to work accurately, but with a little tweaking, it can usually be made to work. I just put a new temp sender in my truck (71 Chevy C10). Gauge was reading high with the new sender, but temp was where expected when checked with an IR thermometer. I added a 10 ohm sensor into the line to bring the needle back down to the midpoint and it's working fine.
