Codes P1174 and P1175, vacuum leak?

CRZYFO0

MEMBER
2008 GMC ACADIA
3.6L
V6
2WD
AUTOMATIC
140,665 MILES

While checking for a vacuum leak using a smoke machine. While running the smoke though the system I noticed smoke was coming out of the oil fill tube in the value cover. I just did the timing chains that took care of the p0017 code. Now I get the p1174 and p1175 code. Got me really confused on how to get this taken care of.

5 Replies

KEN L

MASTER CERTIFIED MECHANIC
48,397 POSTS

How does the engine seem to run? If okay, then continue below:

P1174 refers to a fuel trim cylinder balance malfunction in a vehicle's engine control module (ECM).

P1175, on the other hand, refers to a fuel system lean during acceleration code.

This guide can help:

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

I would check the fuel pressure because you may have a weak fuel pump or the MAF sensor needs to be replaced.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Fuel Pressure (Key ON, Engine OFF) .................... 384-425 kPa (56-62 psi)

You can get a fuel pressure test kit from the auto parts store, they rent them for cheap or free. Here is the location of the MAF sensor so you can change it out. Can you please shoot a quick video with your phone so I can hear the engine running? That way I can tell for sure what's going on. You can upload it here with your response. Check out the images (below). Please let us know what happens.

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Monday, April 24th, 2023 AT 5:21 PM

CRZYFO0

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Looked at video bout system running lean. Already replaced 02 sensor on B2-S1. Checked and cleaned MAF. Runs smooth down the road just really bad on acceleration. My main concern is why is it I'm getting smoke coming into value cover on bank 2 (front cover) when checking for vacuum leak with a smoke machine. Here's a short video of it running.

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Tuesday, April 25th, 2023 AT 11:14 AM

KEN L

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48,397 POSTS

Thanks for the video. The engine looks like it is running fairly well, which is good. The lack of power could be low fuel pressure, can you check it please? I have also seen a bad MAF sensor cause this as well. Don't worry about the smoke test, in most cases it is normal for the smoke to find itself inside the engine. Check the air filter as well and let me know.

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Thursday, April 27th, 2023 AT 9:22 AM

CRZYFO0

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3 POSTS

Okay. Did fuel pressure test. With key on got 18 PSI. At start reading is 60 PSI. Replaced the air filter. MAF was cleaned and with engine running and I disconnect the plug and it stalls out.

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Friday, April 28th, 2023 AT 2:24 PM

KEN L

MASTER CERTIFIED MECHANIC
48,397 POSTS

18 PSI is low. Is this the pressure when you turn the key on or when the car sits for a while? Also, when the MAF sensor is too far gone cleaning it will not help. I would try a new sensor.