So today by Saturn popped the engine light on again!!! It was off for 3 weeks and the readiness monitors were reading good. It the same code p0420 cat below efficiency bank 1. My cat is 4 months old and is under warranty but I will have to pay labor again. I'm not real OK with paying labor for a part that lasted four months. Especially when the cat they used was universal and not a Saturn cat like I was told. Is there anything else it could be? Why would it read OK and then bad all the sudden again. Thanks guys!
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- Thread starter Dakota1820
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Because it was within tolerance (barely) when new and fell out of tolerance so now its tripping the light.
I bet you can install that cat yourself. Probably just 3 bolts on each end of it. 30 minutes with a jack and basic hand tools.
The universal cats are never as good as the real ones.
Originally Posted By: bdcardinal
The universal cats are never as good as the real ones.
Originally Posted By: dparm
Originally Posted By: bdcardinal
The universal cats are never as good as the real ones.
If the engine is not burning the fuel properly: not proper air to fuel ratio, or timing off with valves or ignition, or ignition not proper due to bad plugs or coil(s), or cam worn out, or not keeping the engine at proper operating temperature, or burning too much oil, or some other problem(s), you could put a brand new factory top of the line cat on the car and it will still fail after some time.
So along with the cat failing, maybe the real question is why did the cat fail.
If it were my car I would be looking at how long it has been since a tune up, and also run three tanks of a good gas with a bottle of RedLine SL-1 in each tank to clean the fuel system so it has a chance to meters the fuel properly, if the components are not totally worn out.
And I would also be looking at how many miles are on the engine. There is a limit to how many miles you can expect to get out of an engine and still have it run clean enough to not kill a catalytic converter.
Why would the downstream oxygen sensor not be the main suspect?
...but in such short order? 3 month beginnings of failure? Unacceptable.
There are plenty of Saturns out there burning oil on the original cat like chevy(cant recall his consumption from the other thread, but lets say average for his saturn) that have the original last a good while even with the burning. I'm sure at this rate, he would have been satisfied with 5 years compared to this.
EDIT: Yes, did you ever get the downstream replaced for kicks?
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No not yet. I guess my thinking was it went away for 3 weeks and even passed all the monitors so how could it be the o2 ? Also my cat is welded
Gotcha.
Can you read any part numbers on the cat itself? Did they let you know what brand it was? They will pay for the cat but charge labor again, sorta a waste to go for the same brand again.
Here's a complete redo that might fit your car post cat, but it's expensive.
Complete Magnaflow custom replacement
Otherwise, that price seems way too low in your replacement thread I found months ago for the entire job. The magnaflow legal in cali converter is $251 w/ free shippin on Amazon alone. The link above is for an entire kit 'bolt on' no welding, supposedly.
Either buy the one on Amazon, if the rear 02 isn't the issue; and have the shop do the labor and pay $330+ or put the entire one for $425 on yourself above.
Single converter:
Magnaflow 46222
PS: A lazy 02 will have 'intermittent' codes, thus the go away and return of the CEL/MIL.
ADDED: You can get the 'complete' bolt on for $370ish on Rock Auto with shipping included(not counting use of 5% off code you can use), so save $50 over Amazon right now for that same replacement I just mentioned...so to me if it IS the cat and not the rear 02 then pay the hop but choose either the replacement magnaflow 50 state legal or buy the bolt on and do it yourself(25,000 mile or 5 year warranty, whichever first).
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Is there a way to test the o2 sensor. I can get the part number tomorrow but it was a magnaflow universal.
http://www.saturnfans.com/forums/showthread.php?t=166664&page=3
^You could pull your rear 02 and see if it looks like this guys(97 LS2 I believe?).
He had replacement piping and converter on for 2 1/2 years when the code came back that you are dealing with. Replacing the front 02 sensor with NGK/NTK and resetting ECU kept code away frmo 1,200 miles...back. Pulled his 02 and check out picks on page 3 I linked, caked to the max he says. Replaced, trips trips trip and no codes.
So, pull your rear 02(front should be white if you bother to check it as well). It could wind up being your rear 02 sensor all along if I'm reading this right??
Anyhow, he chose NGK/NTK. See if the rear one is lame. The CEL would have been in open loop more frequently than a rear issue, AFAIK, as a mildly lazy front can still not trigger a CEL/SES/MIL, as that OP experienced, but the issue with the cat related code is rear 02 or cat; for your engine. DOHC, right?
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Well, see the thing is, the forward O2 sensors produce a wave form because the engine is constantly switching LEAN-RICH-LEAN-RICH. The way the cat is checked is it compares the forward waveform to the rear waveform. It does the same waveform, but at a more leveled scale. Peak to peak voltage is lower. So it looks like LITTLE_LEAN-LITTLE_RICH. Just going on either side of stoichiometric. When the rear O2 begins to resemble the forward O2 output; going nearly full LEAN and RICH, then the cat is bad, and the light is tripped.
I kinda dont think its the O2. Because it is making the larger voltage swing necessary to make the computer think the cat is bad.
^Well, he should be able to tell if the rear 02 is clearly caked to the max or not. If it looks really bad, it probably needs to be replaced 'anyway' even if the cat failure contributed to it's failure in the past.
chevy, check for any exhaust leaks, too. Feel all piping between manifold and cat for obvious signs of exhaust air leaking.
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Originally Posted By: bdcardinal
When they were legal, universal cats are no longer legal in CA, they were jokingly called "one time pass" cats for a reason.
Didn't we discuss this few weeks ago? Didn't I say your light will be back? Didn't I rant like lunatic then? If not, I need to do that again :-)
Seriously, the universals do not work. Either accept that or get it replaced.
If you are determined to replace the O2 sensor, replace the PRIMARY O2 sensor. Do NOT bother with the O2 sensor which is plugged in the converter.
- Vikas
O2 Sensors should ALWAYS be replaced when a cat convertor is replaced, just to prevent issues like this from coming up.
First of all, we should look at the conditions that have to be met that kill convertors in the first place.
Too much fuel (running rich)
Too little fuel (running lean and hot)
Too much oil (coats cat, and eventually lights off, damaging catalyst material)
Now think about those conditions.
Two of them involve the convertor being plugged up with carbon.
Guess what other parts are getting covered in carbon, too?
YES! The 02 Sensors!
Always replace them when you are replacing a convertor.
BC.
Well the shop didn't recommend replacing them and I didn't even think about it. Please give me the info on the anti fouler plug thing . Pros cons and how to do it. And yes vikas you did say that. But I wanted to clear it and see if it was a flook or not 
but you were right.
but you were right.- Status
