[balckspecspeede]

Im on my 3rd or 4th battery in the last couple months. Reading came up as a dead cell. So i used my warranty to replace it twice now. Im convinced something is draining my battery???
2nd problem is getting that pesky p0420 code. Its inspection time Anyone have a link for the fix on hand? Ill search it in the meantime.

 

[ten-sec Spec]

yes, something is draining your battery.

 

[i68k]

if you have a stock header, hopefully youve already read the precat and butterfly faq...? hopefully you dont need to rebuild

if youre catless and have a p0420, and you already using 2 antifoulers on the lower o2, you need to check the exhaust for leaks, particularly around the o2 sensors. its possible to have a bad/clogged o2 sensor and get this code, normally both o2 sensors would need to be functional. however, if your having battery/charging issues, there is possibility they were getting shorter voltages than normal, and the ecu tripped it as a bad cat. assuming youve tried clearing it...?

as for your battery, you need to make sure the terminals are super tight, and you have too ground contact to the fenderwall, meaning check the cables for rust/rot/breakage, and make sure there is bare metal contact to the fenderwall. also, double check the connections to the alternator, be careful the bolt under the red cap is live! once youve done that, check your battery voltage motor on&off to check the charging system.

this is also assuming you dont have like big amplifiers or something else running while your motor is off, or not charging properly.

 

[balckspecspeede]

Thanks Guy! I have an aftermarket header. So the o2 sensor could be fouled? Ill check the terminals on the battery but i think my negative gorund is weak. Bolted to the fender wall with aftermarket wire.

 

[i68k]

yes, since you have a catless header, you should have put the 2 antifoulers on your lower o2, as to space the lower o2 away from the exhaust stream. not sure which header/midpipe you have, but the lower o2 is on your midpipe, or its the one closest to the ground if both o2 are on your header. if you didnt have antifoulers, just clear your ses codes after you put them on, so your not driving around so rich, then your p0420 should not come back.

you should fix your grounding issues asap, otherwise you could result in bad charging system, grounded coilpacks, or worse, grounding thru the ecu which causes permanent ecu failure. assuming you used an adequate grounding cable to your fenderwall, and made sure the terminals are unmoveable. so you should probably check your voltages after you fix this stuff, it is hard to tell if you have something draining your system, or your system isnt charging.

 

[yogi b]

"you should fix your grounding issues asap, otherwise you could result in bad charging system, grounded coilpacks, or worse, grounding thru the ecu which causes permanent ecu failure. "

please pay heed

just to be sure i ran two grounds,
from the negative terminal to bare metal on the block and body

 

[balckspecspeede]

Nice pic yogi. Im gonna ground it to the block. I think im losing my charge through the negative terminal. Im also gonna pick up the anti foulers. I have an 02 spec so my primary is on the second bung of the header? Antifouler goes on the bottom bung right? Im going to double up the spacers. If all else fails im going to pay someone to relocate the o2 sensor behind my only cat.

 

[i68k]

you dont need to relocate the o2, but you should be using 2 antifoulers on the lower/secondary o2 sensor, this is the one thats closer to the ground on your header. the o2 sensor that is higher/primary is the one thats closer to the hood, this one does most of the afr, which controls your fuel trim so youll want your primary in good working order.

once you got your battery terminals super tight, and have good ground contact on the negative cable, just check your battery voltage with motor on & motor off, you should see if there is significant drain, or if its not charging, either way gives you a dead battery.

 

[balckspecspeede]

you dont need to relocate the o2, but you should be using 2 antifoulers on the lower/secondary o2 sensor, this is the one thats closer to the ground on your header. the o2 sensor that is higher/primary is the one thats closer to the hood, this one does most of the afr, which controls your fuel trim so youll want your primary in good working order.

once you got your battery terminals super tight, and have good ground contact on the negative cable, just check your battery voltage with motor on & motor off, you should see if there is significant drain, or if its not charging, either way gives you a dead battery.

Oh k im gonna double up the spacers on the secondary/bottom. I dont put any spacers on the primary o2 spacers??

 

[i68k]

Oh k im gonna double up the spacers on the secondary/bottom. I dont put any spacers on the primary o2 spacers??

no, you dont put spacers on the upper/primary o2, its contributing mostly to control your afr, ie your gas mileage, so you want that one to have an accurate reading of whats coming out of the motor.

basically, the lower/secondary o2 is used to double check the primary and to read cat efficiency, so if both o2 sensors are reading relatively the same, a cat code is produced p0420 because the cat should reduce the emission before it gets to the secondary/lower o2. however, since youve deleted that cat in between the o2 sensors, they will always read the same, giving you that p0420 cat code. basically, spacing the o2 away from the exhaut gives it a skewed reading, tricking the ecu into thinking the cat is working properly. it works 99% of the time to remove the ses light.

you should be something like this, with the exception your lower/secondary o2 is at the bottom of your header:
http://www.b15u.com/sentra-specific...oulers-remove-ses-light-o2-sensor-spacer.html

 

[balckspecspeede]

Yup I saw that link. Such a great write-up. I purchased the foulers and i just drilled one of them. Going to install it now!!! Wish me luck. I just hope the dude who installed my header didnt swap the o2 sensors on me.

 

[balckspecspeede]

Great Success! 75 miles of no service light!! 02 with 112k on it. Now the only thing im worried about next is the Head Gasket.

 

[i68k]

awesome, dont forget to check your battery voltages motor on & off, to be sure your charging system is working