Tech Tips
Coolant Temp Sensor ~ 85 Firebird

I just finished this repair and I included it because I didn't know how important this little $9.00 sensor is. The Bird had just come out of the shop for running really rich. They re-routed and re-hooked some hoses, charged me $60.00 but obviously missed some stuff.

I hooked up my new Auto X-ray to my bosses Firebird to get some reference points for my 86 T/A. Her SES light was not on but I got a Code 15 ~ Coolant Temp Sensor Too Low. Her SES light must be burned out. Upon scan I found the sensor was reading -4°. The gauge uses one sensor the ECM another, that's why the gauge still worked.

The ECM thinking the car was freezing was dumping extra fuel all the time. Other results were TCC not locking up and no closed loop operation.

I picked up the sensor NIEHOFF DR134AK $8.99 from
Checker Auto and wired it in. It has updated connections to prevent moisture and corrosion and the leads must be crimped and soldered. The old one took an act of congress to remove. Tech Tip #1 ~ Plan this repair the night before and soak sensor threads with penetrating oil. While I was working I found a broken vacuum tee, don't know if I broke it, and a vacuum hose that was really loose. Replaced these items.

Night and Day. The car now knew how to adjust itself. I no longer had that "rich" choking smell, and it idled like glass. On my cruise to work the TCC locked up giving me better fuel economy and the rich/lean teetered back and forth doubling my O2 crosscounts indicating the car was constantly metering and adjusting it should. And I had closed loop operation with "no trouble codes found".

I noticed the "romp on it cold power feel" was slightly decreased but well worth it when I stopped at a light and the idle smoothed rock solid. Outside of replacing a broken door handle so I could actually get into the car, this was the most dramatic $9.00 repair I have ever encountered (used door handle!!).
I can already tell the difference in gas mileage.

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