Test pipes threw a CEL with CEL fix
 

Hey guys not sure if im posting in the right area or not im new here but I just installed some ISR resonated test pipes WITH a cel fix (basically o2 sensor bungs im sure u guys know what im talking about just making sure lol) but they still threw a check engine light? Anyone know why? Heard its bad to run bolt ons without a tune because it can cause the engine to run lean but all I have are the test pipes everything else is stock.

Later z34s, I'd say '13 up, are less forgiving of test pipes when it comes to a SES. My '14 has test pipes, z1 intakes, and full exhaust. After data logging I've found no reason to believe it's going lean. Unfortunately without a tune you will most likely have to cope with the light shining in your eyes. In reality it should do no harm. That being said you'll not regret the money spent on a tune.

Sent from another dimension.

For minor mods, the ECM will adapt.

Intake mods only - no tune required.
Exhaust mods only - no tune required.
Intake + exhaust mods - tune required.

If the test pipes are going to be your only mod, go ahead and get a tune (not because of the mod but to get max performance). If you plan on making more mods, wait on the tune.


Edit: The O2 sensor may have been damaged during the test pipes install - especially if power tools were used on the nuts/bolts. They aren't very rugged.

Ok thanks man good to know but yeah I am planning on getting more mods but for now ill end up getting just an exhaust. When I get intakes I won't throw them on till im ready to tune. And as far as the o2 sensors they should be good we didn't use any power tools the CEL didn't come on until about a month after the pipes were installed

I've got the Z1 CAI and test pipes on a 14, weirdly the only time I pop a CEL is while using cruise control. I just use a scanner to reset if it happens, always being bank 1 or 2 catalyst too lean.

For the time being you can purchase an OBDII scanner for $15 to clear the code. Then you won't have the annoying yellow message lighting up your tachometer.

Yeah an OBDII scanner is a must for a Z owner. They are a finicky little bitch. Plus there's nothing like a dash light to keep me from living my best life. Best to just clear it and pretend it never even happened...after googling the code of course haha.

Just tune with EcuTek and get the bluetooth dongle when you're done modding. You get added features on your phone + can clear DTCs. Running rich or lean isn't ideal anyways so a tune is recommended.

Anyone know why the 2014 and up Zs O2 sensors are more sensitive? Did the sensors themselves change?

I have a 2016 and I just installed ART pipes and have Stillen intakes and Motordyne exhaust. The I bought the ART pipes used and they came with O2 sensor spacers. No CEL for me after over 100 miles of driving. No tune.

Double post

The newer ECUs have a different control strategy to check for a lean/rich bias of the air/fuel sensor, using the post cat O2 sensor.

With a test pipe and the "anti-foulers", the rear O2 sensors don't switch as they should, since they are 2-3" out of the exhaust stream. Generally they only see the O2 that is "captured" in the anti-foulers. The ECU interperpates this as a lean condition.

I hope that your CEL stays off, however 100 miles is not much of a test.

The newer ECU control strategy will detect the test pipes and throw a CEL of "too lean" due to the post cat o2 sensor being used to detect any lean/rich bias of the air/fuel ratio sensor.

CEL came on after 360 miles. I use a code reader to clear the codes, but of course this now means I just MUST get tuned. ;)

I see that you are an optimist and can find the silver lining in any cloud :)