[Kaseikei]

So today i woke up took a 12 mile trip to pick up my parents and take them to do taxes. After doing my taxes i take them home and notice a CEL came up.

Took the car to see which codes and P015B and P0171 are thrown.

The car is stock except Injen 7300 CAI.

Guy at the autoparts told me to clean the MAS (MAF). I also read on some forum to unplug battery.

Will do those when car is cold.

Any other recommendations?

Thanks

[cooper1965]

Your are running too lean, most likely because of the Injen. That particular unit can be a real pain to tune for, and the newer these cars are, the more sensitive they have become. Its the reason you see some guys get DTC's with certain mods and no tune, and other guys don't.

[Kaseikei]

The only weird thing is ive had the CAI for aBout 8k miles and only now does the CEL get thrown

[wookwook]

This is so far the best article I have seen on the ecu seeing an implausible condition and coding out.


Bottom Line - its one of those things and requires a tune to fix.


this can explain the randomness -paraphrasing my understanding here:

"Some people have the benefit of better Air pressures where they live blissfully inside the compensating window of the ecu while using a modified intake.. Others have a variability in the environment for baro and this can exceed the set limits of the ecu to compensate more easily".....

The MAF is active in steady state driving, which is Not during warm up and during transients. Transients are like during shifting up or down certain hard accel and decel moments and the ECU then refers to a table to manage gas Air to Fuel - AFR.

The VVE table is calibrated to the stock Intake calibration. This is the Volumetric Efficiency table. GM tuners avoid tuning it. Ford uses the table as the primary AFR calibration as they are SD Tuned and GM is MAF (primarily) tuned for AFR, and looks to SD for help during times where air flowing across the MAF is turbulent. MAF is supposed to be a more finer tuned, sensitive, architecture.

ECU looks to VVE for a moment and finds an implausible condition to satisfy resulting in an alert/code/mil/cel.

I don't know what the weather is in Sunny FLA today but we have finally gotten a good layer of frigid air settling in NH.

Like COOPER said, it just may be that model of intake is more trouble than its worth to pursue a tune and all that goes along with it.

https://repairpal.com/obd-ii-code-p0171




A couple of logs to see it... T marks the transient








Here is my Fuel Trim Table and it is need of me going and doing a Recalibration of the MAF after I did some MOD. The recommended variance is +/- 5 percent. So I need to go and tune the MAF.

[Kaseikei]

Hey wook thanks for the detailed reply. Coincidentally i started wasting more fuel since saturday (no cel) after refueling. Im also guessing it could be a bad tank of gas.

Im not discarding the information you guys are saying and i know i will need a tune but 8k miles thisnfar has seen hot temps cold temps (for florida) with no issue whatsoever above 90 and below 60 f

[Davescamaro]

A p0171 code means a lean mixture to the o2 sensor. I would say maybe check for any air leaks on your intake install. A pcm wont know what you have installed aftermarket until a tune is performed. So value in voltage doesnt change when its programmed for a oem air box and then add a intake system.
Just my 2 cents and maybe incorrect, but computers on a vehicle wont change from something it's not programmed for.

[Evil-Bee-NH]

Originally Posted by Kaseikei

Hey wook thanks for the detailed reply. Coincidentally i started wasting more fuel since saturday (no cel) after refueling. Im also guessing it could be a bad tank of gas.

Im not discarding the information you guys are saying and i know i will need a tune but 8k miles thisnfar has seen hot temps cold temps (for florida) with no issue whatsoever above 90 and below 60 f

Was probably bad gas or a loose connection. Maybe even too much moisture got in somewhere. All very common problems that can throw a CEL. I'm not an expert but running lean on just a CAI and a stock tune seems very far fetched given the bolt-ons people have done untuned. Long as your running premium I am skeptical on it being anything but random outside factors like too much moisture or bad gas.

Whiskeyfed ran that setup untuned with zero problems for a year or two in harsher temperature conditions so if it went away on it's own I don't think you have anything to worry about. Instead of dropping hundreds on a tune when your not ready or there yet go buy an OBD2 Bluetooth Adapter and buy Torque Pro for like $5 and be able to clear simple codes. Bad ones will keep popping back up and then you'll know if there's a real problem.

[wookwook]

yup. the tech article talks about barometric pressure though not temps. Density Altitude is out of bounds. i think the likely hood of 02 sensor error is low.

a leak seems likely. Re-tighten the intake. Order a new MAF it's cheap and easy insurance. they do break if you handle it wrong. go to another gas source.
reset the codes per EB. rinse and repeat. Let us know.

[Kaseikei]

Thank you all for your inputs, will do all of the above mentioned. Will be a busy sunday!

[cooper1965]

Nice post earlier WOOK, take a double look at that folks.

I'd agree with checking clamps, or leaks, or possible gas if it was just the po171, but with the po15b also, usually points at the intake. You could have just been riding on the edge of setting it for awhile, and just now setting it. Or, as mentioned, its possible more air is coming in somewhere suddenly. Either way, your car is UN-disputably running leaner than intended, just with the addition of the intake. Lets not forget, just because it works on one car problem free, doesn't mean it will work on all cars the same. I have never seen two of these cars respond identically to the same mod. Lets also not forget the enormous amount of factory calibration changes GM has done between 16 till present. Here is just a quick snap of a stock 16 VS a stock 18.. Pretty extensive list.. A lot of these things can be factors..(Just to clarify, it could just be a loose clamp)

[wookwook]

I'm drifting a but here, Haven't gotten the VVE table to play nicely yet but here's one I found out you can change this and get the VT tables to line up with actual wot cam angles. I need to figure SD out, not quite there.







.

[Kaseikei]

Thank you guys for all your support, thankfully it was a bad tank of gas.

After fillup the CEL went away. No tune now for me but i appreciate all the knowledge here.