I have a 1996 LT4....I have a service code popping up P0420 and P0430. I know what the codes are so you dont have to define them for me. Im just wondering if I need to by 02 simulators or sims to fix the problem. Im figuring its my 02 sensors since I just installed Corsa exhaust and not both of my cats all of a sudden messing up. What do you guys think?

 

Did you install the Corsa system behind a totally stock exhaust system with the stock CATs? If so installing the Corsa system should not have affected the rear O2 sensors at all. Not unless the Corsa system relocates the rear sensors down stream. In that case sometimes I have heard that with the relocation the sensors tend to become less active. Which could cause the PCM to throw a code.

 

yea go for the simulated O2s or reprogram the ecu i mean its obvious that there isnt enough backpressure in the exhaust to create the heat needed for the sensor the work properly...BUT...its hard to find them and the only place ive ever seen them for a vette is http://www.lingenfelter.com/Merchant...Category_Code=
im not sure if i did that right if it doest work just go to lingenfelter.com and go to the search option and type heated sensor and it will come right up...this is a good idea to do anyway since the sensors are going on 10yrs that is if they've never been replaced
chad

 

You may be right, but I had some O2 issues early on, and did some research on them; how they are made, how they work, what makes them fail, heated vs. un-heated sensors, etc...And, nowhere in reams of material from various manufactures did I run accross 'lack of back pressure' causing a reduction of heat resulting in O2s failing. Besides, the LT4 uses heated O2s, if I'm not mistaken.

I did read where contamination from oil leaking down into the units by way of the wires opening, or the opening being closed off/blocked (I used RTV once), and speaking of RTV, some silicon based sealants/gaskets will kill O2s regardless of where they are used in the engine. Some other honorable mentions were specific fuel additives and "octane boosters" will kill O2s. But, the #1 cause of failure seems to be connections and not the sensors. It would make sense to buy one of the O2 sensor test jigs and measure the actual peformance or scan the sensor voltages on a scanner before jumping to any conclusions.

As for installing sims - even driver controllable ones, wouldn't doing so would effectively put the system in "open loop", yes? The computer would be using some bogus fuel metering voltage value based on the sim voltage, and not the actual conditions. It is easy to see how the mix could alternate between rich or lean - I guess - in any case the O2s are an essential part of the fuel metering system. I suppose that in certain applications a sim would be useful, but it would compromise fuel economy and emmissions, etc. in a daily driven vehicle.

It's just me, but I would rather troubleshoot the cause rather than install a "work-around" solution, except as a short-term way to isloate a problem...at least on a daily driver. No?

P.

 

The ECM is just telling you the cats are not as effective as they should be. A couple of things could be causing this. An exhaust leak would be my first look because of the fact you just changed the cat back and I suspect you had to do some moving around to get the old stuff down. Also possibly the tune could now be off a little because of the new exhaust being more efficient. I would take a look for leaks first. O2 isms will defiantly take care of the problem and will not cause it to remain in open loop since if the cat is working properly the rear O2's have very little change anyway.

 

Bosch Heated 02 Sensor
Proper O2 sensor operation requires temperatures of 600 degrees Fahrenheit to ensure correct readings to the computer. In some exhaust systems the O2 sensor is unable to reach this temperature due to reduced back-pressure or improper mounting location. This condition is most easily diagnosed from a recurrent SES light or when you observe the computer repeatedly switching between open and closed loop functions. To correct the problem LPE recommends and uses this high quality Bosch electrically heated O2 sensor to replace the stock sensor. The sensor mounts in the stock O2 bung and requires only minor wiring skills. This item not legal for sale or use on California pollution controlled motor vehicles.

im not saying this is your situation because many vette owners use corsa exhaust i was just putting that there to cover my source. but like FD2BLK said it conviently happend right after installing the new pipes and he is probably right about it being a leak around the cat because i think most rear 02s measure the oxygen in your exhaust after the cat to, like FD2BLK said, tell the computer if the cats arent working properly, or "as effective as they should be"