Hi all,

Roger, you are correct in your interpretation. My gauge is reading low all of the time, due to the sender having slightly higher resistance over the old sender( I think. The old sender wasn't functional in the time that I owned the car).

I have an extra gas gauge around here. Tomorrow night, I am going to take a few batteries, and mock up the circuit that you are describing. I have a box full of resistors ( death of grandparent who was a radio nut from way back), so I can play with this until I get it close to correct.

Thanks. This is really interesting. I am really glad that this board has such high quality thinkers here. Pierre, I also appreciate your conservative approach on this. ( Aren't you the same Pierre with the home built T-5 conversion, megasquirt, and so forth? You are voicing a new, less "junkyard wars" message here!)

Thanks guys. My slant is fun, and you all help keep it fun.

Greg

T5? I don't even know how to drive a stick

I use throttle body efi but based on a GM computer, not a megasquirt (yet).

I just hate paying a significant amount for something so simple and having it not work.

Actually, I'm abit on the conservative side, myself. I'll side with Pierre on this one.....it's probably a good idea to do a mock-up and bench test. Ain't it great, being able to use Grandpa's old stuff in yor car!?

You do know the resistor color code, don't you? (Let's see;...Bad boys rape our young girls but violet gives willingly......yeah, Blk, Brn, Red, Orange, Yel, Grn, Blu, Violet, Grey, Whi., Blk is 0 and Whi. is 9 ) So, you would need, for a 20 ohm resistor, Red, Blk, Blk. There might be a silver or gold color band on the end. This indicates tolerance....gold for 5%, silver for 10%.

Roger

Whatta ya think, Roger? This would save me some effort, since I already have the sender out. Would I get the same effect?

Thanks,

Greg

I have the same problem after installing a new gauge from the same place. My old one was also toast. In my case, however, I am beginning to expect it may also be the voltage limiter. I noticed that my temperature gauge never gets above 120. Nonetheless, I am curious to see you rtest results in case I need to go that route as well. Thanks.

Mike

Sure....you should get good results doing a "dry" bench test. I might suggest you try to get hold of a variable DC power supply, though. With something like that, you could vary the supply voltage and see if it really is the sender, or too low of an output from the voltage regulator. Start with a 5VDC output, and see what results you get with a guage and sender, then crank it up to 6VDC, and then 7VDC, maybe even hit the 1/2 volt points between. That should give you some really useful info.

Roger

I am suggesting that I put the resistor in parallel with the sender rheostat, instead of across the gauge terminals. If we do this, the gauge will get some voltage through the resistor, and give a little more voltage at the gauge.

Whatta ya think? I don't think that I got my idea across with the post from this morning.



Greg

Well, that's the idea I was trying to get across, but I sorta figured it would be a little more difficult putting it across the sender while mounted in the car. Electrically, it should be the same, whether across the sender or across the guage terminals, but I digress.

Roger

I think it would be easier to do it on the sender because you wouldn't need to take the dash cluster out. I think the sender goes through the bulkhead, not sure. Or at the connecter between the rear harness and the front. On my 71 duster, this conenction is located behind the drivers kick panel.

Hi all,

Okay, I tried the resistor in parallel trick. It did move everything towards full, but at least in my case, I couldn't get the range right. If it read full when the float was up, then it would not read close to empty when the float was down. Evidently, the resistance scale is not linear.

What did work was fooling around with the star wheels on the back of the gauge. I moved the top one counterclockwise, and it moved the needle towards full. These little star wheels are really hard to move. Be careful, but this works.

Thanks to Roger, Rafa, Pierre, for the help. This would be a good addition to Chuck's article on voltage regulators, maybe?

Thanks guys.

Greg