C&L stuff = running too lean?

[BlackVert]

I recently installed this stuff on my 1996 GT Convertible:

C&L Mass Air Kit
C&L True-Flow pipe
AccuFab 75mm Throttle Body
C&L Upper Plenum

I had vaccuum leaks for a while, but I am 100% sure they are all fixed and there is no more leak. But I am still getting 2 "too lean" codes, one from each side.

I have reset the computer (by disconnecting the battery) at least 3 times. After the car warms up, it pings when I am accelerating, even though I am using high octane gas. Before long, the codes come back.

Is it possible the computer can't handle the improved air flow? Should I set my timing adjuster back to 11 (stock), reset the computer, drive it a couple of days, and then advance the timing again?

 

[mogs01gt]

Yes those will make you run lean. The MAF sort of "tricks" the computer into reading the air/fuel as lean. That is why you make feel a increase of power.

Im not sure of Trick is the right word though.

 

[BlackVert]

Yes those will make you run lean. The MAF sort of "tricks" the computer into reading the air/fuel as lean. That is why you make feel a increase of power.

Im not sure of Trick is the right word though.

But it pings now, so maybe it really is too lean? Should I back the T/A down to stock? Or 12?

 

[vrpirata]

Like two years ago I got a C&L MAF for my previus Stang, it made it run Lean like hell similar to what just happend to you, I got two codes, they where something like "bank ? too lean", and the car ping under acceleration. If you have an scanner or a PC based OBD II scanner (I have one now) you can monitor the STFT and LTFT (short term fuel trim and long term fuel trim), they are porcentages and the ideal condition is that they should be within +/- 10% for all rpm's but wot, if they are bigger than 20% that would trigger the OBD codes for "bank ? too lean".

Positives values for STFT and LTFT the computer is commanding the injectors to add more fuel because a lean condition is detected at the O2 sensors, Negative values means the computer is commanding the injectors to add less fuel because a rich condition is detected at the O2 sensors, the STFT and LTFT are computed with the MAF sensor input information for the pulse duration of the injectors, so what you have is your Computer trying to compensate for the wrong information coming from the MAF sensor by adjusting the STFT and LTFT... and the MAF sensor reading is affected by the C&L MAF housing.

The solution is: get your stock MAF housing back in, check your STFT and LTFT and you will see how they come within spec again. I wish somebody told me this when I was struggling with the C&L MAF two years ago, it took me some time and a lot of reading to find out

Now, if you really really want to use the C&L MAF, then this is what you can do to get rid of the Lean condition (you will need an OBD II reader, the PC based is sold for about $100):

1. Get more sampling tubes for different calibrations from C&L and try them until your STFT and LTFT become within +/- 10%.

2. OR Change the fuel pressure regulator for an adjustable fuel pressure regulator and adjust it until your STFT and LTFT become within +/- 10%, this is the way I fixed mine and I had no sideffects, however some people doesn't recommend this http://www.brothersperformance.com/shop/mustang/fuel-pressure-regulators.html

3. OR Get one of those mafterburners and adjust your A/F mixture with it http://www.mafterburner.com/mafterburner_page2.htm

4. OR You can get a Chip costum programmed with the C&L transfer fuction, a programmer can adjust your A/F mixture and therefore get rid of the Lean condition.

You can fix the pinging with the Steeda TA, however that won't fix the Lean condition because the Lean condition is due to the MAF.

Good Luck... you are going to need it

 

[mogs01gt]

But it pings now, so maybe it really is too lean? Should I back the T/A down to stock? Or 12?

Before backing it down, try some higher octane fuel. If that doesnt work, you will have to decrease the timing or put those headers on to richen that air/fuel ratio up.