Codes?

[UndeadGods]

Ok I have been having this problem for some time now.

Engine light came on, scanned it and this is what I found:

1) P0131 Oxygen O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)

2) P0420 Catalyst System Efficiency Below Threshold (Bank 1)

I replaced my O2 sensor (I got used one for free) in summer, but I got a sensor that wasnt for my car, we rewired it (dumb idea) and it was ok, till a few months ago.

My car has really bad fuel consumption. I know most of you are from states so bare with me, but I get about 300km outta full tank (57L ish). It's been getting worse n worse for the past few months.

Another problem is that when I drive I feel like my car has no power, I would literally have to floor it (sometimes, it comes and goes, its not constant) in order to go faster than 60hm/h and still it would feel slow and weak.

I know that the head gasket has been replaced twice prior to me owning the car.
I bought the car with 200,000km.

I read somewhere that the cat doesnt like coolant in it, but I dont know if thats what the issue is here..
I also hear really bad rattling sounds from underneath the car.

When I was undercoating my car at work, I checked the heat shield to see if it was loose. But it wasnt.

I also replaced my fuel pump because it was making buzzing sounds + was losing power.

Do I just need to replace my O2 sensor again with the real one?
Or is my cat gone?
Is it both?
Or something else?

Thanks!

[[ChaosweaveR]]

The LA1 and catalytic converter issues go hand in hand.

Been through this issue before, and again now. Sounds like the ceramic insides of the cat have fallen apart. That's what the metallic noise is, and make sure you replace with a direct fit OEM cat. Universal cats are a huge no-go, as the engine light will not go away. As for your sensor, that's probably shot as well. Dunno what glue you sniffed to wire in a different sensor though.

[AaronGTR]

I agree. I think your catalytic converter may need to be replaced. O2 sensor codes, lost power, poor fuel economy.... all points to clogged exhaust flow.

Replacing your O2 sensor with a used one that isn't right for your car wasn't a bright idea either though, and can also hurt your fuel economy. The cars computer uses that sensor to make fuel trim corrections, and if it's not reading the sensor correctly it can be incorrectly compensating and create a lean or rich condition.

Factory sensors can be expensive, but there are plenty of aftermarket replacement sensors designed for your car available for cheap. Check out rockauto.com, or your local auto parts store, and put the correct sensor in when you change the cat. I'd replace both front and rear sensors to be safe.

[UndeadGods]

I know that it was a really bad idea to replace the O2 sensor with non-OEM one, but I was short on cash, so it was a cheap fix..

Alright, I will replace the cat for sure, as well as the O2 sensor, I might replace the 2nd sensor as well but I must ask this first.

If bank1 sensor is the sensor in front of the cat, and thats what the code pulls for, then the sensor after the cat SHOULD be ok, right?

[bricooper78]

I'd venture a guess that you would be right, BUT if that cat is clogged, the downstream may not be seeing enough of anything, so basically, change the two parts you know are bad, and then clear the codes, and try 'er again, see if you get anything setting off the code reader.

[UndeadGods]

Is there a way of telling if the cat is shot/clogged once I take it off? Will it rattle or show any signs of being bad, or will it look normal?

[bricooper78]

it will rattle, may even get pieces falling out if they're small enough, it may or may not let light through it, usually if that ceramic stuff is broke it plugs up enough to block the light from the opposite end.

ps, do NOT hold it up over your head and point it up towards a light, that would be bad.. mmmkay. use a flashlight, leave it sitting flat. an eyefull of exhaust shrapnel isn't going to do you any good

[UndeadGods]

Originally Posted by bricooper78

it will rattle, may even get pieces falling out if they're small enough, it may or may not let light through it, usually if that ceramic stuff is broke it plugs up enough to block the light from the opposite end.

ps, do NOT hold it up over your head and point it up towards a light, that would be bad.. mmmkay. use a flashlight, leave it sitting flat. an eyefull of exhaust shrapnel isn't going to do you any good

Your a doll!

[bricooper78]

yea

the only reason i know anything at all(which you now know all i know on the subject) is i have a buddy of mine that is at a shop, and i was asking him about high flow cats and exhaust stuff in general..

that's what he told me about them, also told me that in general, unless you are making really big power, a high flow doesn't help, and that the fed has regulations about how much scrubbing those have to do (read: how many square inches of ceramic that the exhaust gas must come in contact with), and how the high flow still have to meet government regulations (for a street car), and usually don't gain you anything.

but as he got to an off road race type application (which idk why you'd have a cat for racing unless you had to due to the sanctioning body), the phone rang, and i gave him some space, and ended up heading out before we reapproached the subject.

the end

[bricooper78]

^^^ and on that, idk how incomplete that info really is, if you went that direction, i'd actually go with the turbo or supercharged guys. most frequently it's AaronGTR (also a mod, but he won't force you to post pics or ban) who will finish off a half-truth bit of info.. which I expect any post now *watching my clock*...with an L.. cLock

[UndeadGods]

Fair enough, I'm not looking forward to spending thousands of dollars to make my car street illegal, I just wanna keep it OEM for the most part

[[ChaosweaveR]]

Grand Ams are too much money to make go fast. Basic bolt ons, and daily drive the fock out of it.

Also...those cheapo projectors blow goats. Do a real projector retrofit.

[UndeadGods]

Originally Posted by [ChaosweaveR]

Grand Ams are too much money to make go fast. Basic bolt ons, and daily drive the fock out of it.

Also...those cheapo projectors blow goats. Do a real projector retrofit.

Such as?

[bricooper78]

search the word retrofit and you'll see.

basically installing a ballast/projector unit in stock headlights.

bolt ons: CAI, free(er) flowing muffler, little bigger pipe, headers, then you get into bigger throttle body, but it's really not much help unless you crack 'er open and put in a cam and go internal...

oh, stickers, no matter what they tell you to the contrary, will not make your car faster, nor do they gain hp.

been peeling them off for 3 months now...

[[ChaosweaveR]]

^Ding

Me, personally, I like the Flowmaster 80 series muffler/glasspack/2.25" pipe combo. No rasp, decent gain, and still affordable. And any CAI will work, they all do the same thing. I know I bought MSD coils and wires, but they don't add anything. Trust me.



Skip to 0:37 to hear the car. And feel free to laugh at my 168HP of fury.

Added: those decals have been long gone.

[UndeadGods]

Originally Posted by bricooper78

oh, stickers, no matter what they tell you to the contrary, will not make your car faster, nor do they gain hp.

been peeling them off for 3 months now...

What if they have word "fast" in them? haha

[[ChaosweaveR]]

Originally Posted by UndeadGods

What if they have word "fast" in them? haha

No. Just...no.

And see my post for exhaust. Do it. Now.

[UndeadGods]

Originally Posted by [ChaosweaveR]

No. Just...no.

And see my post for exhaust. Do it. Now.

Did, I thought GAGT's stock HP is suppose to be around 170?

Ps, your car sounds dirty

[[ChaosweaveR]]

Originally Posted by UndeadGods

Did, I thought GAGT's stock HP is suppose to be around 170?

Ps, your car sounds dirty

They're factory rated 175HP at the crank, not the wheels. Stock GTs usually put down 155-158WHP from what I've seen, so my mods did something. Averaging 165WHP wasn't bad for it's mileage at the time (110,000 miles)

I'm guessing "dirty" means good? Oh, to be a 20 year old.

[UndeadGods]

Originally Posted by [ChaosweaveR]

They're factory rated 175HP at the crank, not the wheels. Stock GTs usually put down 155-158WHP from what I've seen, so my mods did something. Averaging 165WHP wasn't bad for it's mileage at the time (110,000 miles)

I'm guessing "dirty" means good? Oh, to be a 20 year old.

You are only 25 lmao, I'm sure your slang doesnt differ much from mine.
Yes dirty = good.

How much money did u put into that project?