PLUMMAXSE

iTrader: (2)

My 99 SE-L is running a little rich after installation of a budget y-pipe. Rich enough that it set off the O2 sensor with 07-07,05-10 codes. I read that as sluggish response from an overly rich cat sensor. I put some Techron gas treatment and ran a half of tank thru the car at a good clip. No more CEL. I'm thinking of going to a Frankencar intake and wondering will that help with leaning out the mixture? I drive short trips and the car doesn't warm up fully sometimes.

njmaxseltd

iTrader: (19)

I assume your Cali Spec????

How is that pipe on your car? Can you feel more pull? How much did the exhaust note change?

PLUMMAXSE

iTrader: (2)

Car is Fed model. Exhaust pull is much deeper and the car pulls just fine especially in the 3 6k range. No problems there!!

Stephen Max

iTrader: (59)

A rich mixture can be caused by an exhaust leak near the O2 sensors (at the header/y-pipe joint). Air pulled in at the leak will register as a lean condition by the O2 sensors and the ecu will compensate by richening the afr. You might want to be sure that your y-pipe is good and tight against the header.

MAXEJA

i also think you need to give the ecu time to adapt the change of having a ypipe on. im fed spec and have not gotten codes but just alot of fun and a great growl.

PLUMMAXSE

iTrader: (2)

Steve,
Do you know what the torque value of those bolts should be set? We are speaking of the 6 nuts that hold the y-pipe to the header.

Stephen Max

iTrader: (59)

No, sorry, not offhand. If I remember, I'll look in the fsm tonight.

seegarman

iTrader: (1)

Did anyone replace all of the O2 sensors while installing the y-pipe? Since my car is at 130k miles, it may be close to replacement time anyway.

PLUMMAXSE

iTrader: (2)

Steve,
You hit the nail on the head!! My rear header/y-pipe was too loose. I must have had a air leak which caused the riching of the mixture. I snugged all 6 bolts up to 40ftlbs. I'm not sure of the proper torque values. But thanks to all who helped. This list is GREAT

Stephen Max

iTrader: (59)

Yup. I know about this because it happened to me. Btw, the FSM said to torque to a range of 32-38 ft-lbs. Sorry I didn't get back to you about this earlier. 40 ft-lbs is fine, though.

PLUMMAXSE

iTrader: (2)

How long did it take before your CEL light stayed off? Mine is coming on every couple of days and I just reset it. Codes 0707 and 0510. Thinking I might have to replaced rear O2. Might try running a couple of tanks of Chevron(93) through her and see if that helps. Hell, a rear sensor from Courtesy Nissan is $70. Thats about the same money.

Stephen Max

iTrader: (59)

According to the field service manual, code 0707 can also be triggered by an air leak. Check the tightness of your y-pipe to cat joint before you go out and buy a new o2 sensor. Buying a new exhaust gasket from the dealer fixed an air leak I had at that joint.