P0171 and P1297

[jpulll]

I’m going through the tuning process with Motoza for the F21 turbo. Long story short I keep getting these two codes that continually pop up. P0171 which is a lean fuel trim code and P1297 which is the pressure drop between the throttle body and turbo. I did end up changing the DV because the old one failed the vacuum test. The new DV did help and I’m boosting stronger. But like I said I keep getting the P0171 and P1297. When these codes pop up, the engine sort of goes into a limp mode where it won’t boost past 15psi. Normal boost is 22-23psi for me.

Now Motoza i feel they keep thinking the MAF sensor is to blame. The reason I think this is because they keep asking for logs with and without the MAF sensor connected.

Any thoughts/experiences?


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[caluma4x4]

Check the turbo to manifold gasket and also the turbo to cat gasket, if these leak, 02 can get in before the first 02 sensor, this skews the fuelling.

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[jpulll]

Okay so I now have new coil packs, which helped the sputtering issue during load, new lower CTS, new N75 a little while back, new DV, and I switched the N249 and N112 to try to eliminate the P1297. I’ve also boost leak tested and yeah I found some things but nothing serious.

For the life of me, I just cannot get rid of that code. I think the P0171 is related to the P1297. So with all this nice new expensive things, what else could be causing this?

I’m starting to think the Motoza tune is to blame because it seems whenever I try to do a log for them, that’s when this code pops up. Pretty much every time I’ve started recording logs, the P1297 pops up and boost is limited to 15psi. Very rarely does is pop up from my everyday driving but as soon as I plug in the OBD dongle, the code pops up.

And let me just say, I’ve had so many 2nd gear through 5th gear pulls and the car boosts to 23psi no problem and holds it to redline. So I obviously do not have a boost leak. I just have this weird phenomenon with this code.


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[jpulll]

It’s not advised to throw money at a car before you know the issue but anyways I’m buying a new billet PCV valve and a new N249 valve. I have not heard back from Motoza as far as what they suggest, should hear from them today or tomorrow.


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[Gin+]

I'd be curious to see your logs.

[jpulll]

I’ll start with the PCV valve, pulled it out and the original billet still help pressure so I left it in. With the new N249 valve, part throttle feels better. I thought things felt spiky with the old one, now things feel smoother - as far as being able to hold part throttle. Still feel like the ride isn’t over, but progress is progress.


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[jpulll]

I’ll start with the PCV valve, pulled it out and the original billet still help pressure so I left it in. With the new N249 valve, part throttle feels better. I thought things felt spiky with the old one, now things feel smoother - as far as being able to hold part throttle. Still feel like the ride isn’t over, but progress is progress. Still have yet to have the codes pop up again.


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[Furly]

I'm curious if you ever got this sorted. I also have motoza tune and they told me my last log was fine and a few days later I got these two exact codes. I've boost leak tested it and sorted some very minor leaks that only appeared with 20-25psi of pressure. Everything in my engine bay is new. Yet the two codes always come back within few days of driving and the car kinda pops and sputters if I let off the gas and engine brake in gear. The car also has a little trouble cold starting and I have to give it a little gas for it to idle normally. Otherwise it shakes for 10 seconds before it can idle correctly.

[jpulll]

I ended up changing the N249 valve and the problem has been cured ever since.


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[Furly]

I ended up changing the N249 valve and the problem has been cured ever since.


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Mine are deleted so I'm guessing its something related to the hoses down there. Although i have no boost or vac leaks that I can find with 20-25psi of compressed air. This is gonna be fun.

[caluma4x4]

Not even the injectors?
I've had 3 1.8t's and despite replacing o rings they all leaked.

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[Furly]

Not even the injectors?
I've had 3 1.8t's and despite replacing o rings they all leaked.

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Injectors are brand new bosch 1000cc new o-rings new IE fuel rail new walbro 450 fuel pump new fuel filter and fuel lines. New FPR (return fueling conversion) new maf new n75 valve new DV . 034 breather hose kit. A bunch of deletes with things coded out. Everything was fine til these 2 codes popped up. Boosting 30psi on E85 no problem then suddenly its popping these 2 codes and occasionally blowing holes in my DV vacuum hose. Maybe a bad check valve? I have no boost or vacuum leaks. Idling boost gauge shows -20 -22 inhg

[jpulll]

Injectors are brand new bosch 1000cc new o-rings new IE fuel rail new walbro 450 fuel pump new fuel filter and fuel lines. New FPR (return fueling conversion) new maf new n75 valve new DV . 034 breather hose kit. A bunch of deletes with things coded out. Everything was fine til these 2 codes popped up. Boosting 30psi on E85 no problem then suddenly its popping these 2 codes and occasionally blowing holes in my DV vacuum hose. Maybe a bad check valve? I have no boost or vacuum leaks. Idling boost gauge shows -20 -22 inhg

Do you get thrown into a soft limp mode at all? Maybe you pumped e85 that isn't 100% and it's causing these codes, it would make sense for the p0171 although the p1297 is a weird code to pop up for "watered" down fuel.

You're kind of dealing with a different animal because you've got a way bigger turbo with injectors and also you're running E85. It's my understanding that with a bigger turbo, you didn't necessarily need to run the n249. I could definitely be mistaken though.