Chris Gregg

iTrader: (59)

NO, not another one of those "header" threads. I've just run into something that after a plethera of reading through years of threads on headers, I've not found a clear answer to my issue.

After installing the Cattman headers, I knew what I was in for. I had simply installed my primary sensors into the headers. I left the secondaries plugged in but tied off under the engine cover as many others have done. I had hopes the dreaded SES light would pass my over.....but after about 120 miles, it popped on. I bought an OBDII Scanner, confirmed secondary codes (slow response) and heater codes....no surprise. I erased codes, they came back about 100-150 miles. I finally decided I knew what the codes where and would ignore the light.

Well, my issue is that it seemed I ignored it a little too well. Meaning that I was driving along after about 300-400+ miles of driving with the light on when suddenly, it just went off!

I continued to drive. Shut car off and restarted, CONFIRMING the SES bulb had NOT blown....still coming on. I've continued to drive for about 200 miles with the light remaining off. I ran a code check today, and it says that I have all four codes (2 secondary/2 heater) pending and the same stored in the ecu.

My question is then, WHY would the light go off? If I have stored codes and pending, would it not remain on? OR are they stored because they were triggered previously, but they have failed to appear "malfunctioning" to the ecu enough times to warrent the SES light to trigger?

Interesting, the only thing different I've done recently is consistenly run non-ethanol 93 octane in my car. A local station opened up near my home so it is now easy to fill up every time with E-free.

Anyone with similar experience?

ShocknAwe

iTrader: (3)

Ive had wierd things happen with my 02 codes too. They were on for about 3 days and I was about to just order some new ones and a sim. About every other month I put some Lucas injector cleaner in my gas. Started the car up and 5mins after pulling away the lights went off never to return. I dont know the "official" CEl light but after a certain mileage it DOES just turn off and this is probably what happened to me. Still kinda funky though

95Maxed

Same thing has happened to me. I had an 02 sensor trigger the CLE and then 200 miles later it was gone but still stored in the ecu. Not sure why.

grksoccerkid91

iTrader: (4)

mine used to come and go lol. it was sometimes a surprise because whenever i let someone else start my car or drive it, it would decide not to turn on. it was also similar mile intervals as well.

was it more highway mileage or city?

CMax03

iTrader: (3)

Just install the SIM and call it the day....Never had any lights since header installation iirc 3-4 yrs now....

ranmas2004

iTrader: (2)

THIS ^

Perhaps ECU doesn't consider secondary codes as much of an emergency as other codes and probably clears the light after some time so that you are able to see any other important codes that might pop up. From what I understand you dont NEED secondary O2 sensors and unplugging them wont affect performance because they are just there monitoring the catalytic converters that you removed by installing headers.

Sims are EASY to install. I've had my secondaries SIM'd since I had my Cattman headers...NEVER any SES light. Easier than welding BUNGS IMO, but you can weld some bungs in and screw the secondaries in. If you have inspections in your area you have to do one of the two to pass.

Chris Gregg

iTrader: (59)

Plan to do the sims, but just not a priority...I can ignore the light for now or I'll just erase the codes. More focused on trying to get some other things done like catback and RSB as the light doesn't hurt anything.

Of course, I should have waited to post.....headed to work this morning, light came back on!! I assume it's as I mentioned earlier, so many "errors" sensed by the ecu will kick the light, otherwise it remains pending. That's why it shuts on and off.

Thanks guys!

Shift_Max

iTrader: (18)

Usually a soft code is thrown first which the ecu recognizes. Then it monitors the system and if the issue does not go away, the ecu throws a hard code which triggers the cel.

Grand_hustle17

iTrader: (22)

This happened to me on the way back from maxus (took it through emissions right away lol), it did come back on a few days later....

NmexMAX

iTrader: (22)

Bung them into your headers somewhere. As long as they read exhaust flow, you're fine.

My secondaries are plugged into my primary port, and I have no secondary codes. My primaries are completely unplugged, and of course I have codes for those (obviously).

2000_MAXIMA_KING

iTrader: (30)

Yes this. It happens all the time to me with evap codes, misfire codes because of half way burnt coils that got heated up, and it used to happen with my secondary o2 as well. The only time I had a constant ses for the secondary o2 (00 max only has one, fed spec ftw) was when I had it completely unplugged and it threw the heater code constantly.

MrEous

iTrader: (11)

Just curious but since you're running only secondaries doesn't it throw your fuel map off or put the car in semi-safe mode? Or are you running a piggyback system from your ecu to help that part out? SAFC?
Only sounded backwards to have the secondaries plugged in when they don't control fuel mapping or timing.

RE: ECU light going out...my '99 used to do that all the time. The code was still 'stored' and would only trigger the light after another 100 or so.

NmexMAX

iTrader: (22)

It's load and RPM dependent. So around 1600 RPM, I'll get a rich blip, but it still idles fine, it's just when slowing at a light.

That is about (RPM/load) that the ECU switches from closed loop, open loop, etc.

Also, from the FSM, if the primaries are not found or in really bad shape, the secondaries take over as primaries. This is why my MPG's are still good. And keep in mind too, O2's are pretty much only for idle control and WERY light throttle since the MAF is in charge 98% of the time for AFR.

Sneaky Green

Where can you can an o2 sim nowadays? I went on 02simulator.com and they are backed up on orders and not accepting ant at this time.

Rods03Max619

iTrader: (5)

Going to order me the O2 sim hopefully tomorrow and extend my primaries so I can plug them in....got to find that website that sells them....

Chris Gregg

iTrader: (59)

I've understood why you've done that with your secondaries as I researched many threads where you have addressed this. However, my understanding subsequent to my research was that even if I plugged the secondaries into the exhaust stream, since they are reading the same exhaust gases, would still throw a code because they would fail to recognize a change....which the ecu expects from what it believes should be post-primary cat gases. I understood if they were plugged in, they would require an "anti-fouler" bung for this reason. To plug them in with a standard bung would just result in another SES.

I've found a good Google search for O2 sims will have results. I just don't have any knowledge about which "producer" sells a quality product. There are some out there that will sim all 4 sensors. Others that are just for primaries. Some that are "adjustable" and some that also have built in heater circuit simulation. Not at home, so I'd have to pull my saved links from what I found.....anyone should be able to do the research though. My issue is that most of them looked kind of dinky (shotty, cheap). One I looked at that seemed good, had no casing and therefore could not be placed or mounted near metal...or it would short. I thought to myself..."really?" So, still an issue to finding a reliable source.

dnice02

iTrader: (1)

So if i unplug my primaries i would get my normal mpg back?

cjandura

iTrader: (3)

http://www.amazon.com/gp/aw/d/B00552...7639240&sr=1-6

Rods03Max619

iTrader: (5)

Here is another from somebody in the classifieds found...

http://www.3sx.com/store/comersus_vi...?idProduct=769

03BlkSETE

iTrader: (3)

I have been running Hotshot headers since they first came out (2004). The shop that installed my headers just put the 02 sensors back into the headers in their approximate stock location which obviously means their is no cat between them. I have never thrown a code.

Here's the original thread:
http://forums.maxima.org/5th-generat...installed.html

I can't tell you why I have never thrown a code but I like NmexMAX explanation.

ranmas2004

iTrader: (2)

Thats where I got mine from. No problems with SES light. Order the DUAL O2 Sim.

NmexMAX

iTrader: (22)

If you plug your secondaries into your primary port.




In all of my posts about this topic, you're the one I always refer to.

Rods03Max619

iTrader: (5)

Cool, should be ordering later on today, since my light just stays on and Exhaust ever takes a break....

Yoitsme

iTrader: (2)

Lotta good info in here