BFarrier

so i just installed some LT's with a ORY not running any cats or rear o2. been driving the car for 3 days with the SES light on due to not having my rear o2s and i will be getting a tune next week. tonight the car felt under powered and was bogging down whe i gave it gas it was working very hard. the SES light started flashing. shut car off waited 10 sec then started it up to drive home. was running fine then 30 sec later did same thing. light then whent soild and powere was normal. what could it be? can it be a loose plug wire or the plug connection? I also had to cut and splice my front o2 sensors to reach the plugs but i did 1 wire at a time sodered them then shrink wrapped them there it no way that i can have a bad conection with o2's have done plenty of wiring/sodering. thatnks yall any help i would apreciate.

LS6427

iTrader: (2)

Flashing SES is multiple misfires....and bad or failing 02 sensors cause that...along with bogging down and loss of power with the pedal being pushed down.

BUT........(NOT POSITIVE).....I believe you need to have the rear 02 sensors tuned out when they tune it or it will not run right. You will get those exact symptoms. And anything that goes on with the 02 sensors can be there one minute, then be ok the next, then run shitty again......

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The Mighty Texan

iTrader: (4)

I havent had my rear o2's running for about 2 years now and the car was running great. I first thought it was a plug wire not connected properly or maybe got damaged and is working intermitantly. The front o2s seem like they would be fine as long as you did a good job.. take it into autozone and get the code at least

LS6427

iTrader: (2)

What are 02 sims?

I thought the rears needed to be tuned out OR use those 02 sims?

I know my tuner years ago said he just tuned my rears out and I even still have my factory 1998 02 sensors in place and the wires are all hooked up too.

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go-t

It is a problem with the front O2s... They do all the reading... The rear sensors are just for a check after the cat and can be tuned out the turn off the SES light... Look into buying the O2s that are for 1997-2004 corvettes for use in the front... They fit and you will not need to cut any wires or have extensions, because they have 48"inchish wires on them...

The Mighty Texan

iTrader: (4)

Yeah 02 sims are going to stop the code, when i was going through all the papers from the previous owner i saw them on there but when i went to look at the car there are non and the 02's are just unplugged. Knowing the type of guy this was (3 different types of spark plugs in the engine) i doubt he got it tuned, but it was running good with only an SES light for the secondary air.

I think you tune or have the 02's to get rid of the code but nothing else.. There's a thread on here showing how to make homemade 02s for like $10, pretty much it just is a huge spacer that draws the sensor away from the exhaust while still leaving the 02's plugged in therefor not in use but not throwing a code either.

LS6427

iTrader: (2)

Ah, I see. I always wondered about those rear 02 sensors and the job they do.

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BFarrier

so you guys are thinking its the o2 sensors? i mean i just changed the plugs and it is still doing at and has been happing every time i drive it now. but it took 3 days after my header install for it to happen. the o2 sensors use to be the post cat sensors since they were longer. with about 70000 miles on them..

TurbopigB4C

iTrader: (5)

You need to usually always change the plug wires on our engines when you take the factory ones especially above 50k miles. When you pull the wires off the boots are usually so tight it damages them when pulled off. If you are missing under load my best guess is spark. Plugs or wires likely. I did driveability at the dealer for three years and never saw an O2 sensor on a GM car cause a misfire.

TurbopigB4C

iTrader: (5)

Try and get a shop to pull the codes if it is just a p0300 with no other codes I would say its plugs or wires. I don't think Autozone has a scanner they let you borrow in the parking lot anymore. Buying one is a good investment check harbor freight or the auto stores to get a cheap OBD-II scanner to pull codes.

TurbopigB4C

iTrader: (5)

On O2 sensors it is a big no-no to cut and splice I don't know the voodoo behind it but in GM training it says if a wire is cut, frayed, or chafed on an 02 sensor it should have the o2 sensor replaced. That is why they sell o2 extensions and don't have people just extend them by cutting and splicing.

BFarrier

well i also got a p0133 code or something that said sensor 1 bank one so i am thinking that it maybe the 02 as long at the p0300 codes. i looked under the car today and say that the o2 wire was resting against my header and melted some isulation. but when my bosses wife did the cuttign and splicing i mean she does great work. she soders the two wires then shrink wrap it then all covered in 1/8" insulation. she does great work with electrical and wiring so i am now thinking that it got too hot and messed up one of the wires.

TurbopigB4C

iTrader: (5)

I do great work with electrical too but the sensors should get extensions which would be the proper way to install. If I were a customer and a shop installed my headers by splicing in some wires to extend the o2 sensors I wouldn't be very happy. They make and include o2 extensions with high quality headers for a reason.

itsslow98

iTrader: (18)

This......get some real extensions.

Chief Z

Yup! From experience, get the extension harnesses. If I am not mistaken, solder adds resistence to the feedback loop. This will cause low voltage codes, as well as multiple misfire codes. Switched to NTKs with extensions and everything cleared up.

LS-1Z28

iTrader: (6)

don't solder the wires on the 02 sensors

Also, check your spark plug wires and make sure they are fully seated.

BFarrier

kust picked up 2 o2 extentions brand spanking new for free from a buddy who carbed his ls1 in a 66 chevelle i will use the other o2 i got with extentions and see how they work. i cleaned the o2 i had in originally and the car is running better

BFarrier

bad o2 ended up being the problem still running alittle rich due to not having a tune yet but no more misfires...knock on wood for about the last 45 miles!!