Electrical Gurus

[pontiacgp]

I have had an inaccurate gas level reading for far too long so today I investigated the problem. I verified the sender by taking an ohm reading and then filling it up, took another ohm reading and calculated what amount the was in the tank for the first ohm reading and it pretty well checked out and the ground on the tank is good. Next took a look at the Autometer fuel gauge which tested good. I made sure the ground wires were good but the sender wire was not the same reading I got from the wire at the tank. I changed the wiring so I could get rid of one connector and the reading got better but still seemed on the high side.
Now to my question, when I installed the gas gauge I tapped into the OEM wire harness for the gauges. I stripped the OEM gas gauge wire, opened the strands, slid the wire for that aftermarket gauge through, twisted it and then soldered it. I left the OEM connector intact so if I ever wanted to put the GP gauges back in it would be a simple job. Could I have increased the resistance in the wire with the method I used and if so what method should I use.

Thanks

 

[foxtrot]

The soldered connection is the best connection that you can have. When two wires are soldered together a covalent bond is formed which is really awesome. As long as you applied enough heat and the solder melted when touching the wire you should have a good connection and not a 'cold' solder joint.

 

[pontiacgp]

thanks for the answer, what I am going to do is to cut that section out and re-solder it. What is the best solder to use for this?.

 

[Pontiac455]

Rosin core, stay clear the acid core.

 

[ed1948]

Wondering if there is any corrosion inside the insulator. When you stripped off the insulation was the copper wire bright and shiny?

Also the unused wire as long as the connector is insulated(taped) has no resistance effect on the circuit.

 

[foxtrot]

Also, if you haven't soldered much before, make sure to practice with some scraps of wire. You could also watch a few YouTube videos. The wire should be heated to the point where it will melt the solder. You'll see that the so,dear gets 'pulled' into the wire.

 

[drogg1]

You said it was reading "on the high side". I believe the sender is 90 ohms when full? I wouldn't expect to see more than an ohm or two difference between the sender and the gauge unless there is a corroded or potentially poorly soldered joint somewhere in between. Oxidized wire does not solder together very easy.

 

[pontiacgp]

yes, it 90 ohms when full, 0 when empty. I'll cut that soldering joint out and re-solder it like you guys have suggested. If that doesn't cure it I'll change the wire from the tank to the gauge. Thanks for all your help and I'll report back the results...🙂

 

[deanlemans81]

If ohm reading is not the same between the tank and gauge, there is resistance somewhere in the circuit. I would trace and inspect the wire to find the exess resistance and fix it or replace the wire. if there is corrosion somewhere in the wire, it could case all kinds of poblems in the long run. A properly soldered joint will not increase resistance but a poor solder will. At the dealership, the required fix was a crimped joint with a shrink tube. it eliminated the possibility of a bad solder.

 

[pontiacgp]

Toook a while to get to it but found that the aluminum solid wide from the trunk to the fuse box was the problem. I cleaned up the connection for the guage and that helped but once in a while it would mess up and then stopped working this week. The gauge was pegged at past full so that means it's not getting a signal. I found a store with 18 gauge pink wire put a new wire from the gauge to the pink wire in the trunk on the side of the connector where is has copper strand wire and the gauge is working properly now. That does it with the aluminum wire which will be replaced this winder with new copper wire. I have to find the clips for the connectors so if someone has a source for those please let me know...🙂