P0101 and P0420

nickb2

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#16
Yeah, that pid data should be in grams per second. Air flow ratio. Anything below 10 is suspect and anything over 15 is suspect. Graphing for a MAF is not the best, as the response of the scan tool cannot keep up. Better to just let it in PID data form.

I am really happy you are getting this done and you are learning something. Excellent. ;)

I got carried away with another op here. I feel bad about that.

@Boomer, you are a really cool guy. Only thing I would say here is, make sure you don't hinder the element in the MAF. They are very fragile.

Now that you are getting good readings with your scan tool, o2's should mimick MAF readings.

Anyway, good luck and good driving, and I hope I won't get banned for having told that guy to screw off. Wish me joy!!;)
 

Gus

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#17


As I said before, in a good cat, the rear O2 sensor changes very slowly(could stay high or low, depending on whether the Cat is storing O2 or not), while the front changes constantly between .1 and .9 volts.........but when the rear, "mirrors" the front , the cat is not working........

Your scan tool has the capability of plotting wave forms to check this....you don't have to just look at live data, changing.......the waveform gives you a better idea of what is going on......
 
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Boomer

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#18
On a funny note, I chipped a tooth taking out the garbage. Hurts like a son of a b$tch. Details in life is what gets you.

How do you chip a tooth taking out the garbage? :confused:
Nick you have to be careful my friend. If I remember correctly, you recently jacked yourself up in an ice skating mishap. Take it easy there.:D Thanks for all of your great advice. I did what I could on the drive home with that cycle monitor. Hard to get it verbatim because of roads and traffic. I think I did get number 7 completed though.
 

Boomer

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#19


As I said before, in a good cat, the rear O2 sensor changes very slowly(could stay high or low, depending on whether the Cat is storing O2 or not), while the front changes constantly between .1 and .9 volts.........but when the rear, "mirrors" the front , the cat is not working........

Your scan tool has the capability of plotting wave forms to check this....you don't have to just look at live data, changing.......the waveform gives you a better idea of what is going on......
Thank you Gus. I have to do a little more studying of the tool manual to see if I can figure out how to plot the waveforms you speak of. I do see a page I will upload a photo of.

One question for you guys, do you think the two codes I had were related or, just a coincidence I got them at the same time? I interpreted Kevs initial post to say, if that MAF is a problem, it could be throwing the O2 readings off. In other words, making the cat look bad even though it may not be?
 

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#21
Feel its a lot easier to do a back pressure test on the cat than to fool around with propane, sign of a plugged catalytic converter. P0420 is a type A code, has to be reset, but with low back pressure, kind of says that rear O2 sensor can be defective.

MAF code can be to other air getting into the system, like a loose hose clamp, or just cleaned. Also can be triggered by a plugged cat, if air can't get out, can't go in. A calculated value based on other engine parameters, its out of range. Is a type B code and will reset itself, but with only one CEL that switches on for any of over several hundred problems, don't know unless you have a scanner.

Same old problem with that O2 sensor, with even a mild misfire, fooled by oxygen in the exhaust and enriches the fuel to all the cylinders. Causing a chain reaction that can fry a cat in a hurry. To prevent this, find myself dumping a can of Seafoam in a full gas tank around every 5K miles. And either cleaning or replacing my spark plugs every 15K miles.

But haven't learned how to deal with road salt, last November, drove my 04 Cavalier to the wrecking yard, 150K on it, still a good runner, but that unibody turned into dust. Almost like they are putting some kind of time bomb in that metal.
 

Boomer

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#22
Well I guess when it rains it pours. I have not had the light come back on yet. Truck is running fine. I pulled into the garage last night and decided to check my tranny fluid and coolant reservoir since the vehicle was at operating temp. Coolant reservoir appeared empty. Look underneath and see a lot of spots on floor. Not good. Looked around a bit and didn't see anything. It was late so I called it a night.

Fired it up today and noticed pretty bad dripping from the bottom tranny bolt on rear drivers side. Looks like it had been running down the bell housing. Looked around with my light and noticed all between the intake and rocker cover I could see a little coolant standing. Looking at the s10 forum it seems to be a common problem on this engine. The dipstick appears to be clean oil.

I'm wondering if I didn't have a tiny leak contributing to the codes I had and also, I'm only getting about 13mpg. It didn't overheat or anything but, I don't think I should continue driving it.
 
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#23
Our 93 S10 4.3L engine was all cast iron, can't tell from the photos, but looks like they switched to a plastic intake manifold. Seems like instead of solving problems, creating new ones.

One problem we had with it at around 70K miles, engine was burning a quart of oil every 600 miles. Only a single O'ring was used on top of the valve keepers that changed into dust. Found a Felpro kit that included new O'rings plus the umbrella type seals like found on my old 41 Chevy. Apparently the engineers back then considered them necessary, new kids didn't.

Engine was so badly carboned up, took four treatments of Seafoam in the TB to clean it out. Ha, did this on a back road at 3:00 AM in the morning, left a smoke trail about ten miles long. After this the compression came up to par, never was a problem even with 200K miles on it.

Another problem was those plastic radiator tanks that became brittle and literally fell apart, only choice was to put in another POS plastic. Never a problem before when brass was used.

Ha, feel GM should advertise if you want problems, we have problems. Have plastic intake manifolds on a four banger, not much of a problem, no coolant flow, and just hanging on the side. But putting a plastic intake manifold cradled in a V-6 or a V-8 with a much greater expansion rate, is nothing short of being completely stupid.

Catalytic converters have always been an after the fact emission control device, namely to burn HC's that the engine didn't, should be before the fact.
 

Boomer

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#24
Our 93 S10 4.3L engine was all cast iron, can't tell from the photos, but looks like they switched to a plastic intake manifold. Seems like instead of solving problems, creating new ones.

One problem we had with it at around 70K miles, engine was burning a quart of oil every 600 miles. Only a single O'ring was used on top of the valve keepers that changed into dust. Found a Felpro kit that included new O'rings plus the umbrella type seals like found on my old 41 Chevy. Apparently the engineers back then considered them necessary, new kids didn't.

Engine was so badly carboned up, took four treatments of Seafoam in the TB to clean it out. Ha, did this on a back road at 3:00 AM in the morning, left a smoke trail about ten miles long. After this the compression came up to par, never was a problem even with 200K miles on it.

Another problem was those plastic radiator tanks that became brittle and literally fell apart, only choice was to put in another POS plastic. Never a problem before when brass was used.

Ha, feel GM should advertise if you want problems, we have problems. Have plastic intake manifolds on a four banger, not much of a problem, no coolant flow, and just hanging on the side. But putting a plastic intake manifold cradled in a V-6 or a V-8 with a much greater expansion rate, is nothing short of being completely stupid.

Catalytic converters have always been an after the fact emission control device, namely to burn HC's that the engine didn't, should be before the fact.
Hey Nick, my old 92 S10 had 204,000 on it and the intake didn't leak a bit. Didn't use any oil either. It's still going and probably still doesn't leak coolant.

These 2nd generation 4.3s are notorious for this leak. The upper intake is plastic however, that is not where the leak is. The lower intake (which I believe is aluminum) is where it's leaking. I've read they use a plastic gasket from the factory. I'll be using Fel Pro on the replacement. I don't know if Victor Reinz is any good or not? I'm considering Permatex "the right stuff grey" to seal the ends as opposed to the RTV. I only want to do this job once.

GM must not have been making enough in parts.
 

nickb2

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#26
On a funny note, once saw a guy come to the garage with clear bathtub sealant. I told him "what were you thinking"

He had butchered the whole intake job with this crap. At least it was easy to remove. That stuff only works for shower or bathtub moldings. He was red as a beet when he got the receipt. I said that stuff will never set in engine environment. ;):money:
 

Boomer

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#27
On a funny note, once saw a guy come to the garage with clear bathtub sealant. I told him "what were you thinking"

He had butchered the whole intake job with this crap. At least it was easy to remove. That stuff only works for shower or bathtub moldings. He was red as a beet when he got the receipt. I said that stuff will never set in engine environment. ;):money:
I may not be a professional mechanic but, I certainly know better than to use bathtub sealant.:p
 

Boomer

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#28
I may not be a professional mechanic but, I certainly know better than to use bathtub sealant.:p
Well I changed the intake gaskets (used the metal framed Fel Pros.) All seems well there. I've been driving it for a couple of weeks. On my way to work this morning, the SES light came back on. Evidently it has completed enough cycles to diagnose?? I'm thinking when I get home I can read the codes and look at data? This time I will NOT reset the light. Is this the way o should go about it?
 

kev2

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#29
do not erase at least until you -
check freeze frame, look at ECT, FT's MAP,MAF and those o2 sensor voltages... I did not see anything to resolving the P0101 - did I miss that -

Sometimes the CAT monitors take time to run - there are parameters that need to be meet -
 

Boomer

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#30
do not erase at least until you -
check freeze frame, look at ECT, FT's MAP,MAF and those o2 sensor voltages... I did not see anything to resolving the P0101 - did I miss that -

Sometimes the CAT monitors take time to run - there are parameters that need to be meet -
I did spray the MAF while I had the air breather off to change intake gaskets. At this time, I don't know what codes are showing.