Hey everyone so I found an 02 Saturn sc2 I'm interested in. Looks extremely clean was a one owner until earlier this year the original owner blew the engine up (ran low on oil) so the seller and current owner put a motor in it. Engine pictures look good he did the radiator and all new engine mounts. Car looks great inside and out. What puzzles me is he installed a straight pipe after the flex pipe. He welded the portion of the old exhaust into the new for the o2 sensor but no cat or muffler. Not s huge deal I can put that stuff on myself if o choose. It recently passed inspections with all the monitors ran and ready. He showed me a video that the engine light works but isn't currently on. How can this be ? He said he didn't install and o2 sensor extender or any other kind of trickery to keep the cel off but that it's off. How can this car not have a p0420? Looks like a clean car but this seems very strange to me. I'd rather him say I tricked it here's how I did so than say nothing and the car is just fine with it and no engine light. Thoughts on this?
No cat and no engine light
- Thread starter ram_man
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gathermewool
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Sounds too good to be true.
There are O2 simulators & custom tuning. Though I'm not aware of any tuning software support for "genuine" Saturn engines (1.9L SOHC/DOHC).
No guarantees that the factory calibration supported P0420. Emissions cheating at a OE level has gone far deeper & far longer than most realize!
No guarantees that the factory calibration supported P0420. Emissions cheating at a OE level has gone far deeper & far longer than most realize!
I wonder if he hasn't been deleting the CEL as it comes on. My 01 Sunfire had the code on pretty much permanently. So it was there for the 2001 MY .
I should see something though correct either a spark plug non fouler or electrical harness plugged in to it? I guess it's also possible to program the pcm to not see that fault any longer which isn't a huge deal if you know what they did. It's the not knowing that kills me!
Originally Posted by FordBroncoVWJeta
I wonder if he hasn't been deleting the CEL as it comes on. My 01 Sunfire had the code on pretty much permanently. So it was there for the 2001 MY .
A Pontiac Sunfire has little in common with a Saturn S-series, Believe it or not.....Saturn was not your normal GM Corporate fare when they first came out.
I wonder if he hasn't been deleting the CEL as it comes on. My 01 Sunfire had the code on pretty much permanently. So it was there for the 2001 MY .
A Pontiac Sunfire has little in common with a Saturn S-series, Believe it or not.....Saturn was not your normal GM Corporate fare when they first came out.
Originally Posted by FordBroncoVWJeta
I wonder if he hasn't been deleting the CEL as it comes on. My 01 Sunfire had the code on pretty much permanently. So it was there for the 2001 MY .
Easy to tell with an OBD2 reader, it'll say how long/many miles since last cleared.
Bypassing the CAT on that model year ECU isn't guaranteed to trigger a CEL - it may or may not, believe it or not. He doesn't necessarily have to be doing something nefarious to try and trick you. I installed a cat bypass on a late 90's Mitsubishi (pulled a bad converter) that didn't trigger a CEL. Nowadays they have custom hardware to reposition the downstream O2's to trick the ECU...I never had to do that the one and only time I installed a cat bypass, so I don't know too much about how the ECU fooling thing works. But Google "cat - bypass - pipe" and you'll find companies that sell them (obviously for track) and explanations/hints on how to avoid a CEL.
I wonder if he hasn't been deleting the CEL as it comes on. My 01 Sunfire had the code on pretty much permanently. So it was there for the 2001 MY .
Easy to tell with an OBD2 reader, it'll say how long/many miles since last cleared.
Bypassing the CAT on that model year ECU isn't guaranteed to trigger a CEL - it may or may not, believe it or not. He doesn't necessarily have to be doing something nefarious to try and trick you. I installed a cat bypass on a late 90's Mitsubishi (pulled a bad converter) that didn't trigger a CEL. Nowadays they have custom hardware to reposition the downstream O2's to trick the ECU...I never had to do that the one and only time I installed a cat bypass, so I don't know too much about how the ECU fooling thing works. But Google "cat - bypass - pipe" and you'll find companies that sell them (obviously for track) and explanations/hints on how to avoid a CEL.
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Originally Posted by Mad_Hatter
Originally Posted by FordBroncoVWJeta
I wonder if he hasn't been deleting the CEL as it comes on. My 01 Sunfire had the code on pretty much permanently. So it was there for the 2001 MY .
Easy to tell with an OBD2 reader, it'll say how long/many miles since last cleared.
I guess i've never used a more fancy OBD2 reader. All the ones I have ever used/owned never gave me that read out, but these where also cheaper readers. Interesting to know that they know.
Originally Posted by FordBroncoVWJeta
I wonder if he hasn't been deleting the CEL as it comes on. My 01 Sunfire had the code on pretty much permanently. So it was there for the 2001 MY .
Easy to tell with an OBD2 reader, it'll say how long/many miles since last cleared.
I guess i've never used a more fancy OBD2 reader. All the ones I have ever used/owned never gave me that read out, but these where also cheaper readers. Interesting to know that they know.
run away
I have scan tool to check that and will but I know it was off long enough to get all the monitors to ready status and pass the emissions test.
How can it not throw an engine light for sure. Both o2 without a cat should be switching their voltage signal like crazy and should cause it to throw a p0420 correct?
How can it not throw an engine light for sure. Both o2 without a cat should be switching their voltage signal like crazy and should cause it to throw a p0420 correct?
Originally Posted by FordBroncoVWJeta
Originally Posted by Mad_Hatter
Originally Posted by FordBroncoVWJeta
I wonder if he hasn't been deleting the CEL as it comes on. My 01 Sunfire had the code on pretty much permanently. So it was there for the 2001 MY .
Easy to tell with an OBD2 reader, it'll say how long/many miles since last cleared.
I guess i've never used a more fancy OBD2 reader. All the ones I have ever used/owned never gave me that read out, but these where also cheaper readers. Interesting to know that they know.
Then you sir need an upgrade. My cheap Chinese obd2 running Torque reports it under the "Real Time Info" screen IIRC.
But, I think a) the ECU has to report it b) your reader has to be able to pull it and finally c) the App has to display it. I think it works out something like that...
Originally Posted by Mad_Hatter
Originally Posted by FordBroncoVWJeta
I wonder if he hasn't been deleting the CEL as it comes on. My 01 Sunfire had the code on pretty much permanently. So it was there for the 2001 MY .
Easy to tell with an OBD2 reader, it'll say how long/many miles since last cleared.
I guess i've never used a more fancy OBD2 reader. All the ones I have ever used/owned never gave me that read out, but these where also cheaper readers. Interesting to know that they know.
Then you sir need an upgrade. My cheap Chinese obd2 running Torque reports it under the "Real Time Info" screen IIRC.
But, I think a) the ECU has to report it b) your reader has to be able to pull it and finally c) the App has to display it. I think it works out something like that...
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Originally Posted by ram_man
I have scan tool to check that and will but I know it was off long enough to get all the monitors to ready status and pass the emissions test.
How can it not throw an engine light for sure. Both o2 without a cat should be switching their voltage signal like crazy and should cause it to throw a p0420 correct?
Google it...when we pulled the cat on the friends car, we replaced it with a piece of pipe that we cut and welded right in his garage, and were fully expecting a CEL light to come on - but nope, no CEL. Like I said, Google cat bypass pipe and you'll learn more about why sometimes a CEL isn't triggered. Alternatively, i know you can actually flash the ECU to address a CEL after cat removal, there are companies that will do this.
Also, is the CAT removing O2, I didn't think it did? If not, how would taking out the CAT effect the O2 sensors? They measure the amount of oxygen in the air and not other gasses if I'm correct. Maybe somebody who knows more about that can chime in.
I have scan tool to check that and will but I know it was off long enough to get all the monitors to ready status and pass the emissions test.
How can it not throw an engine light for sure. Both o2 without a cat should be switching their voltage signal like crazy and should cause it to throw a p0420 correct?
Google it...when we pulled the cat on the friends car, we replaced it with a piece of pipe that we cut and welded right in his garage, and were fully expecting a CEL light to come on - but nope, no CEL. Like I said, Google cat bypass pipe and you'll learn more about why sometimes a CEL isn't triggered. Alternatively, i know you can actually flash the ECU to address a CEL after cat removal, there are companies that will do this.
Also, is the CAT removing O2, I didn't think it did? If not, how would taking out the CAT effect the O2 sensors? They measure the amount of oxygen in the air and not other gasses if I'm correct. Maybe somebody who knows more about that can chime in.
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Clear the codes, Look at the Readiness Monitors.....If the Catalyst is "Ready/Test Complete". The car has a altered calibration OR it didn't support P0420 in the first place.
Originally Posted by clinebarger
Clear the codes, Look at the Readiness Monitors.....If the Catalyst is "Ready/Test Complete". The car has a altered calibration OR it didn't support P0420 in the first place.
Good callðŸ‘... have the owner take a video or pic of the current drive cycle or emissions readiness and look for the catalyst..if it's red that's no bueno and something hinky is going on.
Clear the codes, Look at the Readiness Monitors.....If the Catalyst is "Ready/Test Complete". The car has a altered calibration OR it didn't support P0420 in the first place.
Good callðŸ‘... have the owner take a video or pic of the current drive cycle or emissions readiness and look for the catalyst..if it's red that's no bueno and something hinky is going on.
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Originally Posted by ram_man
My 98 Saturn supported p0420 ask me how I know...... so I can't imagine that an 02 didn't.
I'm NOT saying the OP's car doesn't support all the federally mandated emissions software requirements. But I'm NOT saying it does either.
Again....We are assuming that every calibration was/is on the Up&Up with monitored emissions systems standards.....
My 98 Saturn supported p0420 ask me how I know...... so I can't imagine that an 02 didn't.
I'm NOT saying the OP's car doesn't support all the federally mandated emissions software requirements. But I'm NOT saying it does either.
Again....We are assuming that every calibration was/is on the Up&Up with monitored emissions systems standards.....
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