Finished the exhaust on my wifes 2000 4wd CR-V, and it seems that the sensrs aren't too fond of the signal they're getting, and now she gets a constant MIL. Whats the best way to combat this and where can i find the parts? Thanks

 

What exactly has been done to the exhaust? It sounds like you might not have both oxygen sensors hooked up to the ECU properly.

 

removed the stock exhaust system from the header back, and replaced it with a straiter piping all the way back, high flow cat, and a mild muffler. O2 sensor bung was re-installed behind new cat.

 

Okay so you're running both oxygen sensors?

Regardless, you can check the ECU code by following this process: http://www.c-speedracing.com/faq/06.php

 

45-System Too Lean or Too Rich malfunction in the fuel monitoring systems

67-Catalyst system Efficiency Below Threshold malfunctioning or defective catalyst system

Like i said, i need an ECM that ignores the o2 sensors, can you help me?

 

A high flow shouldn't cause those codes. Especially not the lean code. :thinking:

Now, I'm not very edumacated on the CRV's sensor layout, so are you sure you didn't switch the sensors? (impossible on most B series) Beyond that, are you sure you didn't stretch the wires, let the exhaust hang by the O2, etc?

I wouldn't want to send you off to buy a new ECU or an O2 sim if that's not the problem. The secondary O2 sensor isn't used for fuel feedback and thus it shouldn't even be possible for it to cause a code 45.

 

The code said too rich or too lean, or "other" it's broad enough that I think it could be addressing the lack of a cat issue.

Maybe primary and secondary O2 sensors were installed in reverse? Are they different parts?

I think you're going to have a hard time finding an ecu that will play nice with the CRV's CVT transmission... I say, just install a high-flow cat, it'll be cheaper than fooling the electronics, and is your wife REALLY going to notice the performance difference?

Ok, re-read the post, to check my advice. I see you already have a high-flow cat, can I just confirm this is a cat and not a test-pipe?
-PHiZ

 

yeah, its hooked up fine, i think its definately the cat, cause before the install i looked though it and it looked like 2 mesh screens and tahs about it, i could clearly see through it. I dunno, I'm gonna be strapping a s/c on this thing soon, so I don't feel like taking a stap backwards with a less flow cat. Someone suggested a OBD1 conversion harness, and you seem to be an ECM guy....opinion?

 

Did the original system have the o2 sensor in the cat? Cause if it is then thats where the o2 needs to be. If it is after the cat, the sensor is not getting hot enough and throwing codes.

 

We call them ECUs on this side of the yellow ricey line, just to let ya know
I don't have any hands on experience with the CRV. I'm concerned with the interaction between the ecu and 4WD automatic tranny. There might be an option to use an OBD1 CRV ecu. Or a regular honda/acura ecu might work, if the 4WD auto functions are divorced from the ecu.

However you are correct in thinking that OBD1 only uses one pre-cat O2 sensor, and might help out.

Sorry, again just to clarify, are you talking about a high-flow cat, or a test-pipe?
-PHiZ