Misfiring after CBE install

Meulen · 04-28-2014, 08:00 AM

I'm having a similar issue. I installed FI HFC's and CBE. It's definitely misfiring. Light withing the first 100 miles. I don't drive the car much. My mechanic ran the diagnostic and it read "multiple misfires" He cleared the code and the problem went away. I suspect there is a lot of stuff burning off in the HFC's and CBE and the O2 sensors are trying to read things for the ECU to adjust to the new exhaust. My mechanic said to let the HFC's and CBE break in a bit and see if it throws the SES light again. But it seemed fine after he cleared the SES

thangcu35 · 04-28-2014, 08:08 AM

Quote:

Originally Posted by Meulen

I'm having a similar issue. I installed FI HFC's and CBE. It's definitely misfiring. Light withing the first 100 miles. I don't drive the car much. My mechanic ran the diagnostic and it read "multiple misfires" He cleared the code and the problem went away. I suspect there is a lot of stuff burning off in the HFC's and CBE and the O2 sensors are trying to read things for the ECU to adjust to the new exhaust. My mechanic said to let the HFC's and CBE break in a bit and see if it throws the SES light again. But it seemed fine after he cleared the SES

Does your light flashes and what is the condition for that to happen in your case? Mine drives fine in the lower revs and bogs in the higher RPM under WOT. It seems to drive better when the engine is still cold, but after fully warmed up it is much more noticeable. It will blink the SES everytime I try to floor it to redline.

Meulen · 04-28-2014, 08:27 AM

Quote:

Originally Posted by thangcu35

Does your light flashes and what is the condition for that to happen in your case? Mine drives fine in the lower revs and bogs in the higher RPM under WOT. It seems to drive better when the engine is still cold, but after fully warmed up it is much more noticeable. It will blink the SES everytime I try to floor it to redline.

No flash, and no condition really. Just normal driving. When the light was on the scanner read less airflow from on MAF sensor. But once the SES was cleared everything was perfect.

7speed · 04-28-2014, 03:57 PM

Quote:

Originally Posted by Meulen

I'm having a similar issue. I installed FI HFC's and CBE. It's definitely misfiring. Light withing the first 100 miles. I don't drive the car much. My mechanic ran the diagnostic and it read "multiple misfires" He cleared the code and the problem went away. I suspect there is a lot of stuff burning off in the HFC's and CBE and the O2 sensors are trying to read things for the ECU to adjust to the new exhaust. My mechanic said to let the HFC's and CBE break in a bit and see if it throws the SES light again. But it seemed fine after he cleared the SES

Yeah mine flashed shortly after HFC but was fine afterwards.
Not sure what's up with flashing after cbe. Unless you other issues just check gaskets/tightness after HFC to CBE again.

thangcu35 · 04-28-2014, 08:37 PM

Alright guys, I found and fixed the problem. I don't know why F.I. put a mini cat in the pipe before the resonator, but the matrix inside the mini cat came loose and was spiraling all the way to the 18" resonator clogging the exhaust. The reason why I did not notice this is because I bought the catback used and the seller delivered it to me in one whole piece. He told me to install it without taking it apart to reduce the chance of ruining the paper gaskets. I took his words for it and this is the result after pulling the passenger side post cat pipe out.

It took us an hour to pull all the matrix out on the passenger side. I checked the driver side mini cat and it looked intact, but to be on the safe side I gutted it with some long drill bits and lots of cursing. Two hours later..

I used the OEM metal gaskets since the paper gaskets were trashed and so far no leak. The car is noticeably louder, especially now with those mini cats gutted. Power is there and noticeably faster than when I first bought it. I finally got to enjoy driving the Z again.

04-28-2014, 08:00 AM	#1 (permalink)
Meulen A True Z Fanatic Join Date: Aug 2013 Location: Romeoville, IL Posts: 1,093 Drives: 2010 370z 40th Rep Power: 3390	I'm having a similar issue. I installed FI HFC's and CBE. It's definitely misfiring. Light withing the first 100 miles. I don't drive the car much. My mechanic ran the diagnostic and it read "multiple misfires" He cleared the code and the problem went away. I suspect there is a lot of stuff burning off in the HFC's and CBE and the O2 sensors are trying to read things for the ECU to adjust to the new exhaust. My mechanic said to let the HFC's and CBE break in a bit and see if it throws the SES light again. But it seemed fine after he cleared the SES __________________ Follow my build thread here: Meulens Build Journal

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04-28-2014, 08:37 PM	#5 (permalink)
thangcu35 Base Member Join Date: Mar 2014 Location: Fayetteville, NC Posts: 97 Drives: '12 Sport/Tour/Nav Rep Power: 16	Alright guys, I found and fixed the problem. I don't know why F.I. put a mini cat in the pipe before the resonator, but the matrix inside the mini cat came loose and was spiraling all the way to the 18" resonator clogging the exhaust. The reason why I did not notice this is because I bought the catback used and the seller delivered it to me in one whole piece. He told me to install it without taking it apart to reduce the chance of ruining the paper gaskets. I took his words for it and this is the result after pulling the passenger side post cat pipe out. It took us an hour to pull all the matrix out on the passenger side. I checked the driver side mini cat and it looked intact, but to be on the safe side I gutted it with some long drill bits and lots of cursing. Two hours later.. I used the OEM metal gaskets since the paper gaskets were trashed and so far no leak. The car is noticeably louder, especially now with those mini cats gutted. Power is there and noticeably faster than when I first bought it. I finally got to enjoy driving the Z again.