Pre-cat O2 sensor, what problems would this cause? [Archive] - GrandAmGT.com Forum

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coupe
07-19-2006, 06:29 AM
If my pre-cat O2 sensor took a poo what symptoms would the car have?
Hesistation?
Poor exceleration?
Missing?
etc.

Sprucegagt
07-19-2006, 07:14 AM
A DTC code set making the check engine light come on and poor gas mileage.

coupe
07-19-2006, 07:26 AM
My check engine light is on.
Here is the deal and what happened:
I, the idiot that i am did not secure my A/F pigtail. So for a few months it was layin on my rear header. My SES light came on and the idle was all f-ed up and had poor exceleration, so i went to AZ to get the code read, it was an O2 sensor. So i inspected and found my pigtail laying on the rear header completely burned through. So i hardwired it right to the car and threw away the pigtail. The idle is fine now but the car is bogging down and hesitating under light to moderate exceleration.
Now i also suspect the plugs. I got Bosch's for free and figured why the hell not and i put them in. I dont know what kind of bosch they are though, they have 2 prongs instead of 1, really funny lookin plug. I know that bosch sucks on these cars but i didnt have this problem for many weeks AFTER i put the plugs in so im skeptical that its the plugs.

Sprucegagt
07-19-2006, 08:15 AM
Sounds like you shorted the O2 sensor resulting in the PCM just estimating the engine's fueling needs and using the bad fuel timing table. This explains the poor acceleration. Your plugs may be fouled but that is only from the O2 being bad. Clean the plugs, change the O2 and get the code cleared. Your problems should go away.

coupe
07-19-2006, 08:29 AM
How much do these pre-cat O2 sensors run?
Im guessing $100 or more. I just ordered knew plugs from summit with my 'summit bucks'.

Sprucegagt
07-19-2006, 09:57 AM
I got mine from GMPD for about $85 with shipping.

coupe
07-19-2006, 10:10 AM
I found a denso O2 sensor on sparkplug.com.
Its $43, that dont seem right......

Sprucegagt
07-19-2006, 10:22 AM
I would only use the GM sensor. Stay away from Bosch or others.

coupe
07-19-2006, 10:23 AM
Can someone check out that site and tell me if they think it looks like a good buy?

coupe
07-19-2006, 10:24 AM
I would only use the GM sensor. Stay away from Bosch or others.

I figured as much.

coupe
07-19-2006, 10:27 AM
I was told alot of people in the GP community have bought this sensor and it is said to be a great sensor, way better than bosch and equivalent to GM's. Im gonna take a chance and buy it.

NorKoastal
07-19-2006, 01:00 PM
I was told alot of people in the GP community have bought this sensor and it is said to be a great sensor, way better than bosch and equivalent to GM's. Im gonna take a chance and buy it.


Let us know how it goes... My Long fuel trim is kind of suspect at idle (-20+ at times) and open loop acceleration seems to bog more than closed loop driving..

Mods: CAI, UD pulley, SLP catback, and DHP, IAT 1/2 way down CAI

I just Seafoamed and my third gear has more pep with better acceleration.. I still have stock o2's front and back that are stock (50K), and my Maf hasn't been cleaned yet (looks clean through)....

coupe
07-19-2006, 01:14 PM
Ive decided to be smart for a change and buy an ACdelco replacement.
Thats gonna hurt.

Anyone know what size O2 sensor soket i need?

I know someone has a haynes and can look it up for me real quick.

lone_wolf025
07-19-2006, 01:41 PM
Why would your O2 sensor SHORT out from a messed up mix? For the record bad A/F mixtures either burn the sensor (not very likely) or gunk it up with carbon (more likely) which can be fixed just by running the car at a steady 2,000rpm for a good minute solid. Also keep in mind that just because the code says something is up with the sensor does not necessarily mean its bad.

Personally I'd ditch the bosch plugs seeing as how numerous people have had issues with "performance" plugs and just go back to stock.

Sprucegagt
07-19-2006, 01:52 PM
Why would your O2 sensor SHORT out from a messed up mix? For the record bad A/F mixtures either burn the sensor (not very likely) or gunk it up with carbon (more likely) which can be fixed just by running the car at a steady 2,000rpm for a good minute solid. Also keep in mind that just because the code says something is up with the sensor does not necessarily mean its bad.

Personally I'd ditch the bosch plugs seeing as how numerous people have had issues with "performance" plugs and just go back to stock.

You never read the third post in this thread, did you? :banghead

coupe
07-19-2006, 02:02 PM
Why would your O2 sensor SHORT out from a messed up mix? For the record bad A/F mixtures either burn the sensor (not very likely) or gunk it up with carbon (more likely) which can be fixed just by running the car at a steady 2,000rpm for a good minute solid. Also keep in mind that just because the code says something is up with the sensor does not necessarily mean its bad.

Personally I'd ditch the bosch plugs seeing as how numerous people have had issues with "performance" plugs and just go back to stock.




My check engine light is on.
Here is the deal and what happened:
I, the idiot that i am did not secure my A/F pigtail. So for a few months it was layin on my rear header. My SES light came on and the idle was all f-ed up and had poor exceleration, so i went to AZ to get the code read, it was an O2 sensor. So i inspected and found my pigtail laying on the rear header completely burned through. So i hardwired it right to the car and threw away the pigtail. The idle is fine now but the car is bogging down and hesitating under light to moderate exceleration.
Now i also suspect the plugs. I got Bosch's for free and figured why the hell not and i put them in. I dont know what kind of bosch they are though, they have 2 prongs instead of 1, really funny lookin plug. I know that bosch sucks on these cars but i didnt have this problem for many weeks AFTER i put the plugs in so im skeptical that its the plugs.


***

coupe
07-19-2006, 03:43 PM
Well i didnt need a socket. It was loose and i unscrewed it by hand, weird.
You think maybe thats why its acting screwy?

Sprucegagt
07-19-2006, 04:50 PM
It's possible but not likely. If you burnt through the insulation on the pigtail wiring then it shorted the sensor. But if you feel like trying it. Just tighten the sensor up and give it a shot.

White00GAGT
07-19-2006, 05:17 PM
If it was just that wouldn't it just let 02 in from the crack and just make his dtc say that his pre-cat 02 was always reading lean causing it to dump fuel in which would foul the plugs? Its more likely the burned off insulation just shorted the sensor out though isnt it?

Sprucegagt
07-19-2006, 06:46 PM
If it was just that wouldn't it just let 02 in from the crack and just make his dtc say that his pre-cat 02 was always reading lean causing it to dump fuel in which would foul the plugs? Its more likely the burned off insulation just shorted the sensor out though isnt it?

Sigh...... Reading comprehension must not be taught in school anymore. :nono:

It's possible but not likely. If you burnt through the insulation on the pigtail wiring then it shorted the sensor. But if you feel like trying it. Just tighten the sensor up and give it a shot.

White00GAGT
07-19-2006, 07:49 PM
i read your post i was asking you a question to see if thats what it could do if that was the cause. I was also interested in the actual code not just "02 bad", was it always rich, lean or just out of limits? just curious is all.

lone_wolf025
07-19-2006, 11:28 PM
For the record I did read the 3rd post. I did miss the last line about the plugs.

However regardless of how the wires look be they burnt or stripped I don't condone replacing parts without testing them first. That was my main point.

Good luck with the fix.

coupe
07-20-2006, 06:10 AM
How do i test it?

Sprucegagt
07-20-2006, 07:50 AM
i read your post i was asking you a question to see if thats what it could do if that was the cause. I was also interested in the actual code not just "02 bad", was it always rich, lean or just out of limits? just curious is all.

Ahh, I see. I didn't know you were asking me the question. To answer it, yeah your right. The O2 would see the extra air going past it and make the engine run rich and foul the plugs. Plus it will give a DTC for a low voltage signal from the O2 and / or slow response from the O2.

coupe
07-20-2006, 07:57 AM
So what should i do?
Clean up the stocker and try to use it?
Buy a new one?
Bosch or denso? (denso is highly recomended by the GP guys and they use the same O2 sensors)
New plugs should be here today, summit has scary fast shipping.

Sprucegagt
07-20-2006, 08:49 AM
Get a new O2 sensor. If the GP guys are having good luck with the Denso unit then get it. Then either clean or replace your plugs.

You can't easily test an O2 sensor. It is very delicate and requires specialized test equipment. Just appling a multimeter across the signal leads can damage it.

coupe
07-20-2006, 09:07 AM
I figured it was a touchy little bastard lol

Im just gonna order a denso i guess.

coupe
07-20-2006, 10:09 AM
Bah i said screw it and bought the denso from sparkplugs.com. Through searching clubgp.com i found that if you use 'dodgetalk' in the coupon code box you get 10% off. So for $45 TOTAL i got a new O2 sensor.
Im still gonna try and mess with the stocker just for the fun of it.


I got an old timer on gaoc saying that the stock O2 sensor just needs to be cleaned up and reinstalled and that should fix the problem more than likely. What do you think about that Andy?

Here is the link:
http://www.gaownersclub.com/forum/showthread.php?threadid=62376

Yeah i utilize both sites lol

Sprucegagt
07-20-2006, 03:55 PM
I got an old timer on gaoc saying that the stock O2 sensor just needs to be cleaned up and reinstalled and that should fix the problem more than likely. What do you think about that Andy?

Here is the link:
http://www.gaownersclub.com/forum/showthread.php?threadid=62376

Yeah i utilize both sites lol

I think he is going off of what he knows with his 96 GA. That car used a 3 wire O2 sensor. The 99+ GA's got a 4 wire sensor. What's the difference? The three wire has one - ground wire, one + signal wire and one + heater power wire. While the four wire has separate ground wires for the signal and heater power circuits. Also this narrowband sensor operates between 0 - 1 volt DC. Only wideband O2 sensors use a different voltage range of 0 - 5 Volts DC. This is a big reason why you can't just swap sensors and expect it to work. Also put some of those DTC's he listed in the search engine here. See what the results are.

As for using GAOC. Its a good idea, but you didn't tell everyone there the full story up front like you did with me. Plus you added in more detail then here. I didn't know you fried all four wires. I thought it was just the purple signal wire you fried. Either way the outcome is the same.

If you want to be sure, just tighten the O2 back up and plug it in. Then take it to AZ and have them clear the codes. They will do it, you just have to ask. If it goes away then great, but I'm pretty sure you'll get a code again.

It sucks that your not closer to where I live. I could hook up my PT and we could watch the O2 signal going to the PCM and easily verify if it is working right or not.

coupe
07-21-2006, 06:15 AM
I think he is going off of what he knows with his 96 GA. That car used a 3 wire O2 sensor. The 99+ GA's got a 4 wire sensor. What's the difference? The three wire has one - ground wire, one + signal wire and one + heater power wire. While the four wire has separate ground wires for the signal and heater power circuits. Also this narrowband sensor operates between 0 - 1 volt DC. Only wideband O2 sensors use a different voltage range of 0 - 5 Volts DC. This is a big reason why you can't just swap sensors and expect it to work. Also put some of those DTC's he listed in the search engine here. See what the results are.

As for using GAOC. Its a good idea, but you didn't tell everyone there the full story up front like you did with me. Plus you added in more detail then here. I didn't know you fried all four wires. I thought it was just the purple signal wire you fried. Either way the outcome is the same.

If you want to be sure, just tighten the O2 back up and plug it in. Then take it to AZ and have them clear the codes. They will do it, you just have to ask. If it goes away then great, but I'm pretty sure you'll get a code again.

It sucks that your not closer to where I live. I could hook up my PT and we could watch the O2 signal going to the PCM and easily verify if it is working right or not.


Yeah its hard for me to give my story the exact same on both sites becuase some poeple take me in a different direction from here and there, kinda hard to explain.

I am sure the O2 is done for. I am probably not gonna mess with the stocker at all. Im just gonna waite for the new one to come in. Its scheduled to be here the 26th. I hope i didnt mess anything else up by frying those wires. I am gonna try to get pics of the O2 and the pigtail so you guys can see the damage.

coupe
07-24-2006, 03:03 PM
Here are the pics of my stupidity.


http://i34.photobucket.com/albums/d104/Rand81/100_5056.jpg

http://i34.photobucket.com/albums/d104/Rand81/100_5054.jpg

http://i34.photobucket.com/albums/d104/Rand81/100_5052.jpg

http://i34.photobucket.com/albums/d104/Rand81/100_5050.jpg

coupe
07-28-2006, 01:21 PM
New O2 sensor is in.
Pulled PCM fuse.
SES light was out on start-up.
Drove it to work today.
Car drives PERFECT now, just like it should.
4 miles into the drive light comes back on.
WTF?