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Throwing a P0420 code does this not allow the engine to run in closed lopp control; P0420 code
Topic Started: Oct 28 2013, 06:40 PM (846 Views)
nwgeo


Throwing a P0420 code does this not allow the engine to run in closed lopp control. This is in my new to me 96, which on closer inspection looks like the previous owner or shop it was bought from installed a USED cat. :coffee
:bigpop

Thanks in advance.
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Johnny Mullet
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Fear the Mullet

On the Metro, the downstream sensor is simply a monitor and does not change the ECU settings.
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dayle1960
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Fastest Hampster EVER

You can pull the downstream O2 sensor and put it next to your passenger side strut tower and then plug the bung. The P0420 CEL will then go away.

Go and price a new downstream O2 sensor for a metro and you will soon see that plugging the bung is very cost effective.
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vr4


Johnny Mullet
Oct 28 2013, 06:46 PM
On the Metro, the downstream sensor is simply a monitor and does not change the ECU settings.
+1


I lost no mpg when I was tripping a p0420
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vr4


dayle1960
Oct 28 2013, 07:05 PM
You can pull the downstream O2 sensor and put it next to your passenger side strut tower and then plug the bung. The P0420 CEL will then go away.

Go and price a new downstream O2 sensor for a metro and you will soon see that plugging the bung is very cost effective.
The sensor isn't the issue so he should have no reason to price a sensor.
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sjbene123
Advanced Member
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my 96 was throwing the same code it had no cat on it i used 2 spark plug non foulers had to drill out the first 1 to fit sensor in it 18mm was the size i believe then it would still throw p0420 about 1 a month so i added a 3rd non fouler .....now it has a functional cat lol :D
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nwgeo


Thanks very much for the replys. I had done a search on the P0420 code and found what you all had explained. The used looking cat on my 96 sounds like it has a loose chuck of ceramic in there. I think I will remove and plug the down stream O2 and find original cat from a used engine/geo. :whistle

Good to hear it will not effect MPG as I saw there was a statement that it would effect it slightly above 50 MPH.

It has some other problems like serging and a fluid leak at where the pipe exits the water pump(Going to get a used pipe on Saturday to repace my leaky one and see if that does it.) Working on it. ^o)

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evadfa


I am having a MPG drain on my 97 metro 3/5. I thought it could be the CAT or the downstream sensor, so I bought a sensor but now I read that this may not be the issue. I went from 45-46 MPG down to 41. still ok, but I have to take a look and also get the codes scanned to see what the exact problem might be.
I already changed the upstream O2 sensor, and I JB welded/sealed the holes in the muffler and pipes. Lately it has started to sound loud like before so I think that means there are more holes in the exhaust.
Anyone have any ideas on fuel economy.
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Waldo
Jack of all trades, Master of none
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sjbene123
Oct 28 2013, 08:28 PM
my 96 was throwing the same code it had no cat on it i used 2 spark plug non foulers had to drill out the first 1 to fit sensor in it 18mm was the size i believe then it would still throw p0420 about 1 a month so i added a 3rd non fouler .....now it has a functional cat lol :D
I have a '98 Metro and tried the same thing. It cleared the 0420 code but soon got another code that indicated the rear O2 sensor wasn't working (because is was out of the stream). I tried EVERYTHING to clear the issue. Finally just bit the bullet and replaced the CAT. 3k miles, and no more problems. It was the best $180 that I've ever spent. lol

BTW, we have emissions testing here and can't have ANY codes.
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Waldo
Jack of all trades, Master of none
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evadfa
Oct 30 2013, 12:00 AM
I am having a MPG drain on my 97 metro 3/5. I thought it could be the CAT or the downstream sensor, so I bought a sensor but now I read that this may not be the issue. I went from 45-46 MPG down to 41. still ok, but I have to take a look and also get the codes scanned to see what the exact problem might be.
I already changed the upstream O2 sensor, and I JB welded/sealed the holes in the muffler and pipes. Lately it has started to sound loud like before so I think that means there are more holes in the exhaust.
Anyone have any ideas on fuel economy.
1) A heavier than desired right foot is the first thing to check :drivin

2) Compressions would be another, since a wore out engine has lower compression, which results in lower power, which results in poor fuel mileage :x

3) Tune-up, when was the last time the plugs, wires, distributor cap, rotor, and air filter were replaced? :-/

4) I've recently noticed that the "winter" grade fuel is out. You can expect a 8-12% decrease in economy until summer arrives. My Metro dropped from a steady 52 to 47 MPG after filling up with winter grade fuel :hmm

Good luck with finding a solution. I'm sure many more will chime in soon :cheers
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