[65625]

2010 1.8 hatch
before installing the CAI, I had a CEL pop up only during winter time. That code was P1421.. but this was a very fickle code; she would fuck off before I could even figure out where my scanner was. Well I ended up being bold and manic one day and decided to put in a cold air intake. Ha. After installing everything. Blam. New code. P0171. Okay so my brother and I tore everything apart and checked for leaks. (We used the steam method). We did notice there was a hissing noise coming from the intake manifold. So we yanked everything apart and found that the gasket was a tad wonky- okay nbd. We replaced the gasket (and the spark plugs while we were in there). Threw everything back together and she was good as new !
Later on in the evening I came home and started the car up, and Blam. CEL. Ran the codes- the same old fucking too lean bank 1. And the p0507 code. I was able to do the whole idle relearn procedure, and by doing so that cleared the p0507 code. So I started it back up and after a few moments of idle around 700-800rpms the damn p0171 came back.

am I pretty much SOL and have to put back in the OG parts? Any type of advice is appreciated!

 

[65625]

the issue is the location of your pcv port. It HAS to be AFTER the maf. The engine in the crank case is technically metered air. So by having the pcv port before the MAF you are changing the airflow that is being metered. Also: having less than 6" of run between the MAF and throttle plate can cause serious air flow frequency issues which can lead to the maf getting strange readouts during certain conditions such as off throttle and snap throttle.

Thanks for the reply! Well I put the original snorkel on, and rerouted everything.. I redid the idle learn procedure except it didn’t work this time 😳 my brain is so fried I’m going to post a picture of the current set up; .. short fuel trim is -0.8% and long fuel trim is around 28.9% and the RMPs are hanging out around high 600 and love 700s.. which it’s my understanding the automatics normally idle around there 😩

 

[65625]

are you sure that that MAF adapter is the EXACT same ID as the oem unit? even being .5mm off can make the tune completely wrong on the car. with the fuel trims being like that, I would bet that is your next issue.

Ohhhh yeah, made sure the adapter was correct. BUT since my last response, I replaced the MAF. Now I have the magical code P0113 which pops up with my traction control lights. 🤨 I got rid of the too lean code, and rpms are holding steady, and shes driving normal.. but the p0113 has me baffled (it doesn’t take too much tbh😅) I also haven’t ever encountered this code or have yet had a chance to research it lol

 

[65625]

Does that ltft fuel trim get closer to zero if you hold 2k rpms?

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Yes actually, as it sits it’s ranging from 7.0-8.0 but when I go to 2k, it goes down to -2.0 and such 😳

 

[65625]

Also, my intake air temperature is allegedly-40degrees 😳

 

[65625]

The -40 indicates an open circuit on that sensors signal wire. If you check that wire with the engine on, I bet you'd see 5v there, which it should never see unless the circuit has an open. I'd start there, since it could probably cause a lean condition.

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Well, she’s reading at 4.97, so gonna assume this means I get to search for messed up wires? 🤭 which is exciting because wiring is not my forte 😳

 

[65625]

Ok, you should have less than 100mv or .100v on the orange wire and less then 5v but more then 0v on the violet wire. Test with conn ctor plugged in and the key on.

If you have 5v on both wires, you have an open wire between the sensor and the ECM on the orange wire. If you have 5v on the violet and 0v on orange, your new sensor is no good.

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Funny you say that, for shits and giggles my brother and I took back the maf I replaced it with and exchanged for the new one. No CEL since! Knock on wood thanks so much for all your help, y’all have no idea how much I appreciate it!