Help with Aftermarket Guages

[r0nin89]

So I have a full custom panel with auto mete and sunpro guages in my camaro. My speedo and fuel guage give me problems and was wondering if anyone knew some tricks to trouble shoot. My speedo once pretty much a month decides it wants to go from 20mph to 80 to 100 to 120 to 30 to 120 to 40 to 105 ect you get the point. I'll turn my car off for about 30mins and go back out and it will stop. I am running a mechanical line to a transmitter behind my guage that feeds and electric signal to an electric analog gauge. So basically I am going from mech to electrical. Anyone even have this problem? I am running an arctic white autometer.

My second problem is with my sunpro fuel guage. I paid my mechanic to put the sender in a hooke it up to my guage but the thing just seems borked. I'll fill the tank and it will tell me 1/2 full then about 30mins later it will say full. But then it seems to drop faster than it should. It just acts weird like that. Is that normal for an aftermarket guage?

I know that people have told me stock fuel guages sometimes dont work on thirdgens so dont expect aftermarkets to be much better but I know the speedo shouldnt be doing that...

[WildBillyT]

First and foremost, check all of your connections and that you have a solid ground. The fuel gauge problem in particular sounds like it may be a loose connection.

[r0nin89]

Thats good to hear... I hope its something simple like that...

[WildBillyT]

You may be surprised at how important a secure connection and especially a good ground really are.

Certain things (like MSD boxes) are especially sensative and won't work right with an improper ground. Older fuel gauges (60's and 70's, maybe even later) will shoot up to way past full with an improper ground, and if it is a loose connection the gauge will be all over the place. I'm not sure if this is the case in your car, but it is worth a look.

Did your mechanic install a new sender? Do you know what the resistance of it is vs. the range for your gauge?

[r0nin89]

He installed a new sendor for my fuel gauge. I think he may have used the stock wiring though could my problem be there?

[V]

well make sure the sender is the correct Ohm range for the gauge, also make sure the sender is set and adjusted properly. I have a VDO sender from an old project that came with a gauge set and i never installed it because it was more complicated to get it right with the float and all then just to use a factory one.(i had several spares) GM oem sender ranges are 0-90 OHMS(1950s up i think)

IMO aftermarket senders arent any good with gas tanks that are an odd shape like in 3rd and 4th gen f bodies. They are almost a triangle shape, the aftermarket senders are designed for a consistant depth tank. so when use in a tank that gets narrower as the level drops, an aftermarket gauge WILL "speed up" as the fuel level goes down. Factory gauges compensate for this i believe.

As long as the wires arent cut, exposed or loose, the stock wires should be fine. also make sure the sender is grounded properly.

[r0nin89]

Yeah, idk I'm gonna send it to my mechanic and say fix what you ****ed up because I am sure as hell not paying for what he said he could do. As far as the sender its the one that matches the guage so no problem there...