Hego?

I discovered the HEGO fuse was blown in my SC. What is HEGO, and what's linked to that fuse?

My gas gauge hadn't been working (as in not moving at all, w/the needle at 9 o clock)--it seemed to move a bit after I replaced the fuse, but it's still way past E. Is the fuel gauge on that fuse?

Will, the HEGO is the O2 sensor. I think it stands for 'heated exhaust gas oxygen'. The fuse is probably for the heater in it. The heater heats the sensor up to 900 degrees until the exhaust is at full temperature.

I have no idea how long the fuse has been blown, so what would be the consequences of it not working? Bad A/F readings, running rich or lean?

Mercutio said:

I have no idea how long the fuse has been blown, so what would be the consequences of it not working? Bad A/F readings, running rich or lean?

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I would think it would throw a CEL. Not sure...

It's possible it just recently blew in the course of my "Rip out all the wiring!" project.

I've had O2 sensors stop working and the symptom was that it ran like crap at part throttle, misfired and lots of black smoke. It would make it look like it was real lean to the EEC so in turn the EEC would keep giving it more fuel trying counteract the "lean" condition. At WOT it ran Ok. If the fuse is only for the heater it would probably just run crappy when cold and smooth out when warmed up. The heater is just used until the exhaust comes up to temp. It's possible that you wouldn't even notice the difference.