Fuel tank temperature sensor? Rich idle, stalling.

[casman86]

I have a '96 S14 JWT ecu in a '95 S14 and I'm getting code 42 (0402) which is fuel tank temperature sensor. I looked through the FSMs for both years and apparently this is something they added in '96, my '95 doesn't have it.

My question is if this affects fuel and timing? I'm having issues with stalling and really rich idle (10-11:1afr). I have all emissions removed, knock sensor bypassed. I've tested basically everything at this point. If the fuel tank temp sensor absence might be doing this I'll wire one up, but don't want to waste time if it's a useless sensor that doesn't change any ecu parameters.

[ka4life87]

I never knew the s14 has a fuel tank temperature sensor, u sure its not a code for fuel tank pressure sensor? If its pressure that purely emissions and wont affect performance or fuel ratio at all

[casman86]

Yep it's for fuel tank temperature sensor. I compared the pinouts and they started it in 96, obd2 crap. I'm gonna assume it doesn't matter just like the IAT. I finally found my issue after wasting about a week doing diagnostics, dirty MAF! This was one of the first things I should have checked! My idle voltage on my cobra maf went from .8v dirty, to .5v clean. My car went from idling in the 10/11's to the 14/15's or even leaner when hot. It also richened up the top end significantly. I used a q-tip and 91% alcohol to clean the wires, they went from black with buildup to shiny silver. Clean your MAFs everybody, they get retarded.