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Discussion Starter #1
ok so that last few weeks i have been getting this code. a few times i got p0135 and p0130 which leads to front 02 sensor. p0420 leads to cat. so i have been doing some research and i see a bunch of guys saying to try lacquer thinner in the gas to see if that clears out the code due to possible clogging of the media. so before i dump this in the tank i figured i would run it by you guys to see if there is any merit to this of is it some much bs? if it works then i will give it a try also some say to move the lat 02 out of the stream by adding 2 spark plug extenders. i have done that to a geo metro when i was experimenting with water into hydrogen. that helped to keep the front sensor off but did not help with mileage as the 02 just compensated for the lack of 02. also i have tried acetone for that metro and it did not help so that makes me ask before i just dump this into the tank. thanks
 

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P0420 Catalyst System Efficiency Below Threshold (Bank 1)

This means your front HO² is arriving at it's end of life, you may have a bit of cat contamination but this should clear once you change the HO² sensor and drive it for a few hundred miles.
 

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Discussion Starter #3
coby7 i have a new 02 sensor in the front. i just changed it about a week ago and being i do not drive this car much i just reset the code. if you recall i asked if that code p0130 would reset itself but no one replied and said either way so i just reset it. it was a rockauto 02 sensor.

so it sounds like your telling me i have to change the front one again or the back one? or are you saying once the front one has been changed i need to drive it some time to get the cat back to normal? if that is the case then it may take quite a bit as the car maybe see's 20 miles a week.



i confused being the code leads to cat inefficiency? thanks coby7
 

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Did you get an ACDelco HO²?
 

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Discussion Starter #5
Did you get an ACDelco HO²?
don't know if it was or not if i can find the package and it has any of that information on it maybe i will be able to tell. i reset the light the other day and i drove 60 miles yesterday on a visit to kids and it has not returned so maybe it just had to be driven. i will let you know if it returns and then go get the ac delco 02 sensor if the code leans to that. thanks
 

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People on here have had bad luck with Bosch and NTK where they wouldn't last very long or wouldn't work at all. Chances are it just needed a good run especially if you touched the end of the sensor with your hands.
 

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Yup can't be any other brand. Has to be a.c. Delco the rest fail and good luck sending them back.
 

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Discussion Starter #8
again thanks, if it keeps showing up i will just not mess around and will just go and get one from ac delco. i have to see if i can find the box this one came in but by now it is most likely in the landfill. and i don't think the place i got it can tell me. anyway thanks for the help. if it does return i will post it and the codes that showed up for more help in troubleshooting.
 

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Discussion Starter #9
so i got the p0420 code again after my first post on this back in sept. i did not remember the make of it but i do not drive the car much at all may have put 200 miles on it since then. and now in the last 2 days i returned back to work and now i got the code again. so i must have got the wrong one, seems it shout not have went out this fast.

so rock auto has them for like 50.00 or might i want to vist advance auto and pay 80.00 but then if it fails i may have a warranty? or what parts store offers a warranty.

last time i went thru the 02 sensor issues was on a 95 lebaron and i spent hundreds trying t get that one corrected and the last one came from the dealer and they did not stand behind it either. if that is the case and i get another one and i get the code again i just put tape over the light and forget it. tired of all the money on stupid stuff.
 

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Rock auto is where most buy them. I have a business account so I get discounts at the dealership so I went there. 120k km later and no issues.
 

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It could still be your cat. I would clear the code a few times and see if they clean themselves out.
 

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Discussion Starter #12
It could still be your cat. I would clear the code a few times and see if they clean themselves out.
yes coby7 i plan on trying that out before i get another one. but like the talk has been if it comes back after a couple of drive cycles then that 02 sensor i put in may not be what the car should have in it. thanks
 

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Discussion Starter #13 (Edited)
ok i hooked up a harbor freight scanner and did some looking around in the ecu. this is what i got after it warmed up. see if these number make sense to you? for a bad b1s1 02 sensor or cat being i got the p0420 code last.

at idle b1s1 .085 .665 on the graph at 2k rpms .385 .695 i think this was the front but seems like it should be the bac as the front should be moving up and down a lot.

at 2k rpms b1s2 .750 when i raised the speed it went up and when i lowered the speed it went down, that makes sense

cat temp idle 1040 temp at 2k rpms 1090

if i have to go and check it again let me know. also tell me what i need to be looking at on the scanner and info to bring back if this makes no sense. about all i ever did with this scanner was clear codes and see what code it had, never did much in the back pages with it.

also the im monitors are all good but the evap and the cat they have an x in the field so my guess is after i cleared the last p0420 fault that may have reset the monitors and now they are starting to reset. thanks
 

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The first HO² should be all over the place ( Upstream Bank 1 Sensor 1 (b1s1))
 

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Discussion Starter #15
that is why i put in the numbers. i know b1s1 should be moving because it is adjusting the fuel and b1s2 should be holding more steady if all is good. and the cat is doing its job. at first b1s2 was moving just like b1s1 and then it calmed down, i think it may have been open loop at that time as i just started it up. and that is why i put in the cat numbers and temps. to give you an idea how the system was working.


so i will just drive it now and see if the code returns. if it does it may be the b1s1 02 sensor i put in causing the fuel to be off so far the cat is not able to keep up with it. i will then see about getting the ac delco sensore you told me about. it may be i got the wrong one. like i said before i did not pay much attention to it. they gave me one and i tossed the box not thinking i had to get the ac delco type. thanks
 
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