I cleared the engine codes in my car to have the p0180 code remain active immediately after clearing it. 

 

From my research, this code is relevant to a fuel temp circuit A. http://engine-codes.com/p0180.html

 

My gas tank has been swapped from a 95. The car's original fuel pump and sender is swapped in, as well as all the vent lines retrofitted to match the 96's purge canister system under the car. I also swapped the car's original fuel tank harness onto the new tank.

 

I have noticed my yellow warning lamp hasn't come on after running 400 miles on the same tank of gas (still hard to believe!)

 

MY car is required to pass emissions, for which my registration is illegal right now.

 

Any ideas of grounding a wire or adding a resistor to fool the ECM? I was trying to tackle a p0420 code, but it seems i was able to clear that one (straight pipes, no cats, w/both o2's present)

 

 

Temp sensor is built into the sender unit IIRC.

Do you have the sender from the other tank? Was it the same?

 

You could check resistance of the temp sensor. Make sure the terminals in the connector are clean. Other than that I think you'll have to pull the sender unit and replace the sensor if possible. I think you have to replace the whole sender unit just to get the sensor though.

The sender on the old tank was broken for the variable resistor, but the thermistor did work. I don't want to risk damaging it by removing the assembly again if i can avoid it. 

 

I find it stupid that my registration is illegal over a code that is irrelevant to the engine's emissions performance. 

 

The original sender unit was damaged by replacing the fuel pump upon re-installation, before i owned the car. I swapped the units when both tanks were out-of-car. I would like to avoid removing the sender if i can, as to not damage this one. I'll double check the pigtail as that is a variable in this equation.

Oh, and one more thing, is circuit A in the main sender unit, or the secondary unit. I  never did swap the secondary sender, but i have it off the original tank already.

Pretty sure its the pump side. Should have 5 or 6 wires there. Two for the pump, two for the level sender, and one or two for the temp sensor depending on its design. Definitely double check any wiring you might have done just to be sure.

Would anyone know the resistance value for the thermistor, that if my wiring harness checks out, i'll be fine with shoving a resistor in the plug and call it a day. My car is loaded down with half another one, so it will be a day or 2 before i can inspect it.

Not sure how long it will fool the ECU since it uses the temp sensor for checking the operation of the emissions systems, but worth a shot. Pick any resistance that's within the normal range of a temp sensor and wire it in. Might work.

I'll look into that. Thank for the idea