Engine backfires after Roto-Fab CAI Install - Page 3 - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

evonschu · 07-02-2013, 02:01 PM

Mine backfires too. A lot more if the engine is cold. I have only a k&n air filter on stock intake. I personally like it and get a kick out of scaring people downtown. I have a scan gauge II and do not see any LTF or STF readings to show ita running excessively rich or lean. I have the adaptive exhaust disabled.

kmthor00 · 07-02-2013, 03:44 PM

Does Roto-Fab have any comments here?

hawk02 · 07-02-2013, 05:58 PM

Quote:

Originally Posted by KD Innovations

Absolutely correct. By changing the intake you are either going up or down the MAF curve and each car will respond a little differently. The car is going to lean out or run richer (and get worse mileage and pop).

Like they say, you don't HAVE to get a tune but with most intakes you don't HAVE to. By not doing so though, your MAF is not calibrated properly. In fact, you don't know how it is calibrated or what fuel it is demanding at a given mass air.

If you read Ted Jannetty's JRE ZL-1 No Tune Pulley Rotofab Testing Results (http://www.camaro5.com/forums/showthread.php?t=259566), the Roto-Fab intake had perfect fuel trims up and down the MAF curve and the AFR at WOT repeated that of the stock air box. That sounds to me like the Roto-Fab, at least on his ZL1, manages to keep these parameters within spec of the stock tune. I would think most other ZL1s would perform similarly.

As others have said, the only way to find out if the Roto-fab is the culprit is to go back to the stock intake and see if it still backfires.

vetterm37 · 07-03-2013, 09:34 PM

it sounds like a small leak down stream of MAF sensor.

hawk02 · 07-05-2013, 03:06 PM

Quote:

Originally Posted by vetterm37

it sounds like a small leak down stream of MAF sensor.

I have a GoPoint ODB2 scanner. I pulled fuses 2 & 5 overnight to reset the ECU. This afternoon I went for a ~25 mile drive. LTFTs were -3% for bank 1 and -4% for bank 2 when I finished. STFTs were all over the place, but rarely in double digits (positive or negative). I'm no fuel trim expert -- would these values indicate a vacuum leak downstream of the MAF?

hawk02 · 07-06-2013, 02:06 PM

This morning I re-installed the factory intake and then went for a 21 mile drive with my GoPoint ODB2 scanner hooked up. LTFTs at the end were +3% for both banks (yesterday with the Roto-Fab they were -3% and -4%). I gather from this that the Roto-Fab is making my car run rich which would explain the periodic backfire.

TripleBlkZL1 · 07-06-2013, 02:32 PM

Quote:

Originally Posted by hawk02

This morning I re-installed the factory intake and then went for a 21 mile drive with my GoPoint ODB2 scanner hooked up. LTFTs at the end were +3% for both banks (yesterday with the Roto-Fab they were -3% and -4%). I gather from this that the Roto-Fab is making my car run rich which would explain the periodic backfire.

I knew it lol.

djnice · 07-08-2013, 06:32 PM

Quote:

Originally Posted by vetterm37

it sounds like a small leak down stream of MAF sensor.

Why do you say that? I am just curious because tunning is an interesting subject that I want to learn more about.

07-06-2013, 02:06 PM	#34
hawk02 Coupe Newbie Drives: '23 CT5-V BW, '21 Corvette HTC Join Date: Jul 2011 Location: Columbus, Ohio Posts: 3,465 View My Garage	This morning I re-installed the factory intake and then went for a 21 mile drive with my GoPoint ODB2 scanner hooked up. LTFTs at the end were +3% for both banks (yesterday with the Roto-Fab they were -3% and -4%). I gather from this that the Roto-Fab is making my car run rich which would explain the periodic backfire. __________________

07-02-2013, 02:01 PM	#29
evonschu Drives: 2013 Camaro ZL1 M6 Join Date: Oct 2012 Location: Hillsboro, OR. Posts: 179 View My Garage	Mine backfires too. A lot more if the engine is cold. I have only a k&n air filter on stock intake. I personally like it and get a kick out of scaring people downtown. I have a scan gauge II and do not see any LTF or STF readings to show ita running excessively rich or lean. I have the adaptive exhaust disabled.

07-02-2013, 03:44 PM	#30
kmthor00 Drives: 2013 ZL1 Black Join Date: Oct 2009 Location: Frankfort, Illinois Posts: 248	Does Roto-Fab have any comments here?

07-03-2013, 09:34 PM	#32
vetterm37 Drives: 2013zl1&1972 vette:2010sierra Join Date: Mar 2013 Location: calgary Posts: 18	it sounds like a small leak down stream of MAF sensor.