TTORA Forum banner

No cat, no CEL and terrible mpg.

2K views 8 replies 5 participants last post by  RockyMtnToy 
#1 · (Edited)
1996 tacoma 3.4L Auto
So a younger, dumber version of myself decided to chop off my cat and run without O2 sensors. Well I got tired of the CEL on and I figured it would be bad long term to run on a pre-made fuel map, especially at 8k ft elevation.

I went ahead and bought replacement pipe that had the O2 sensors holes/studs and threw in two denso O2 sensors but still no cat($$). I then cleared all emission related codes.

That was 2 months ago and 2-3k miles ago. I still have no CEL, running no cat. I know the 1st upstream O2 sensor adjusts the fuel map and the downstream O2 sensor tells if the cat is working properly. Since there is no cat I should be throwing a code still.

I havent really been driving super long trips lately but the past few days ive been doing a decent amount of miles. The same trip 4 months ago took 1/2-1/4 of the fuel as i'm using now. I'm assuming these problems are related.

If you have any ideas post up! Thanks!
 
#2 ·
Keep in mind that it's cold out now.. your fuel economy will go down a lot in the cold.
 
#3 ·
Maybe the light burned out or that younger dumber you cut the wire from the ECU that drives it. Hook up a scanner and see if there are any stored codes. If you don't have a scanner just don't fuck with this shit at all. They aren't that expensive anymore.
 
#4 ·
Winter fuel formula out now? That'll drop the mpgs by 2-3
 
#5 ·
I had a CEL, replaced O2 sensors, cleared codes and started the truck. The light did not burn out and no wires were cut. Even if they were cut that should throw a code? The bad mpg has been happening since the new exhaust, long before winter blend was out.
My scanner isn't showing any codes. Even if I had a faulty O2 sensor shouldn't it throw a CEL?

I'm more worried that prolonged driving will fuck up my engine since I don't think the fuel map is on point (especially living at 8k feet elevation)
 
#6 ·
You need to mess around with a real-time OBD-II diagnostic tool then. I have several and like the flexibility of using my OBD-Link MX since I can read it on my phone and it makes it easy to export logged data. That being said, bluetooth isn't as responsive as a wire would be.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top