Cel On After New Exhaust Fitted

[walkoau]

Hi guys,

Had a new exhaust fitted today. Full 3" turbo back. Anyway on the way home the CEL came on.

Just wondering if anyone else has had this prob after fitting there exhausts?

I do have a scan tool here but the bloody thing won't link. I'm thinking it has to be the 02 sensor.

Thanks.

[KiwiRS4T]

Hi guys,

Had a new exhaust fitted today. Full 3" turbo back. Anyway on the way home the CEL came on.

Just wondering if anyone else has had this prob after fitting there exhausts?

I do have a scan tool here but the bloody thing won't link. I'm thinking it has to be the 02 sensor.

Thanks.

Could be the warning light for the cat converter - shouldn't be too hard to fix.

[DaveM35]

You got an AXIS yeah?

Don't think our cars would throw a CEL from the O2 due to cats since the only O2 is upstream of them. Maybe it wasn't screwed in tight enough and it's getting bad readings or maybe it was unplugged or wire got damaged during the install. Did you fit it yourself?

I've seen loose ones on other cars cause engine lights so I'd try check that or visual check the wiring to it.

[scotty nm35]

There is no cat warning light. Good chance it is the ecu going into lean limp mode. The ecu should have been reset after such a serious mod, now it needs to be reset so it learns the new fuel requirements.

You can't just use an obd2 reader, none of them connect. Our car isn't obd2 compliant.

[GOD12A]

Possibly P0420 code. Not unusual for picky ECUs with aftermarket exhausts.

As Scotty mentioned, ECU reset and see if that helps. If it pops up again, throw a can of upper head cleaner through it, that has fixed a few P0420s for my clients.

Worst case, rip the cat off and clean it properly.

Absolute worst case, move the cat/O2 sensors to near factory positions.

Hope it helps.

Mark

[walkoau]

Dave, yeah axis. And I was thinking same thing... 02 is up stream so cat wouldnt effect that.

I had it made and fitted by Windsor exhaust shop. They are local with a good rep.

First thing I checked was 02 plug, and checked it was tight. Double check wiring tomorrow.

Scotty, sucks they are not obd2 compatable. What tool do I need to scan it?

How do I do a ecu reset? Is it as simple as the skylines and just disconnect the battery?

Thanks for your input guys.

[DaveM35]

http://www.skylinesaustralia.com/forums/index.php?/topic/261557-Ecu-Fault-Codes---The-Easy-Way%21

I've never posted a link to another topic so not sure that will work but the ecu reset is detailed here, if my link doesn't work try search function

Could you access the actual O2 bung on the new exhaust to check sensor tightness? My stock one is pretty much impossible to get to without a crows foot spanner bit or without dropping the gearbox crossmember all way down till you can fit a spanner up there. It's probably not an issue but maybe last resort check

Ecu reset sounds like best idea, go from there I reckon.

[walkoau]

Dave, yes I used a crows foot to make sure it was tight.

I looked at your link. fault code is 0135 which I believe is 02 sensor. but I could not get the procedure to clear the code to work.

surely the procedure is just to give you the code and clear it...not to actually reset the ecu to learn the new fuel requirements??? correct me if im wrong.

[scotty nm35]

I use a (knock off) Consult3 to diagnose, it's the only way to read all ecu's. There are other options, like the Osirus cable, but they only talk to the engine afaik. I have used a Snapon scan tool with some success, but it needs to have the Japanese software loaded. You can reset the ecu to some extent using the manual method, but I can't guarantee it will reset the long term fuel trims. Disconnecting the battery won't help.

I hope they didn't damage the sensor, it's quite tight up there... Perhaps try a new one if the code returns?

[DaveM35]

Yeah you'd need a scan tool to reset engine adaptions. If you clear the code maybe the ecu will correct itself before it stores again anyway.

I've never heard of anyone having this problem on an m35.

[scotty nm35]

I've never heard of anyone having this problem on an m35.

Not with my dump pipes anyway.

[walkoau]

I wanted to buy yours Scotty but buy the time I.got the dump and front pipe from you, then a cat back from import monster or the likes, the price was getting up there and then I still would of had to install myself.

Just made more sense to get it all from the same place.

[iamhe77]

Is the o2 sensor on a bend by any chance?

[PN-Mad]

They may well have dropped the sensor or hit it hard. Dump pipes are not the easiest thing to get off as a first timer....

[walkoau]

It's not on a bend. It's on the straight section between the bend just before the cat and just after first bend from turbo.

Went back to the exhaust shop today, let them know I wasn't happy and made it clear that its there responsibility to fix it. He said 02 sensor was very rusty and hard to get out so they may have damaged it then.

End of the day they are going to take care of it. I'm dropping it back to them tomorrow.

[scotty nm35]

Why isn't the o2 in the stock position just after the turbo? You can't just go around moving sensors and expect them to run as per factory. Narrowband sensors need to warm up as quickly as possible, directly in front of the turbine outlet flow is the correct spot.

Where did they mount the cat, in the dump pipe?

[walkoau]

The cat is at the lower end of the dump pipe.

So Scotty do you think the 02 sensor is simply in the wrong position and that's all what's causing the problem?

[scotty nm35]

Possibly. It's up to you to fault find this one, as I doubt the exhaust shop will help much. It's taken me 5 years to perfect my Stagea dump and front pipe, there is a lot more to exhaust design than just making a pipe from here to there...

What did they use for a turbo flange? I assume they re-used the stock one, as laser cutting a new flange one off is cost prohibitive. So it's a mild system?

[walkoau]

It's mild pipe with stainless mufflers. I'll take some pics tomorrow when its on the hoist.

Not sure about the flange i will check whilst on the hoist.

And if they don't help! I will demand they put my stock exhaust back on and give me a full refund.

[DaveM35]

Try get them to swap the sensor and if that doesn't fix it, it'll probably have to be welded back in stock location. What else could it be? Unless you've developed a mixture changing fault that's unrelated to your new exhaust at the exact same time as getting your new exhaust.

Sensors are pretty simple but better to stick to stock locations. Maybe the flow and pressure in the pipe has changed too much to give it good readings where it's mounted now.