Aftermarket fuel gauge help

[Courterman08]

I'm trying to get this Autometer Phantom gauge to work on my turbo LS1 swapped '89 and I have no clue where to start. I did a search on here and didn't find anything even remotely close to what I was looking for.

The previous owner has it wired up somehow but it's obviously not right. With a full tank it sits at E, and after driving for a bit it's now at around 1/4 tank. (not really sure how you can wire a signal wire backwards? if that's even possible) Any help would be appreciated. I'm pulling the dash back off tomorrow to figure out what's going to what.

Thanks,
Zach

 

[Scruggs86.5T]

It sounds like he didnt change out the sender in the tank to match up with the new gauge when he got it. The sender is basically a variable resistor in line with the gauge this is why the gauge changes when your fuel level changes. There are different ranges of resistance that senders have, that being said there are different resistance ranges that different gauges will use. Some examples of this being 0-30, 0-90, 73-10, 16-158, 0-280 ohms. Our stock sender is 4 ohms=full and 110=empty. In your paticular situation it sounds like he didnt change out the sender and he put in a gauge that reads opposite the stock sender.

sender- 4/full 110/empty

gauge- 110/full 4/empty

To correct this you would need to find out what range the gauge wants to read and get a universal sender that matches the gauge or the simplest way would be to change back to the stock gauge.

 

[Courterman08]

Thanks for the help, Scruggs. I think you pretty much cleared up all my questions. If that's the case (him putting in one that reads the opposite) then it's not too big of a deal for now. As long as I remember to fill up when it gets to close full haha.

 

[Scruggs86.5T]

It might not be an exact opposite though, I wouldn't rely on it getting up to full. It could be something like;

sender- 4/full 110/empty

gauge- 160/full 4/empty

in which case it would never read full. Or

sender- 4/full 110/empty

gauge- 70/full 4/empty

and it would read full before you were actually close to empty.

 

[Courterman08]

Thanks again Scruggs... I found some info about the gauge. Looks like it's 73 ohms empty, 10 ohms full.

http://www.summitracing.com/parts/ATM-5815

I guess they make a programmable one but it's $120. I also need a Speedo, so there's another ~$200 if I wanted the same brand/style.

edit: my gauge could be one of many choices... I'd have to pull it out of the dash and see if there's any markings on it.
http://www.autoanything.com/gauges/65A4126A0A0.aspx?kc=ffproduct