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Discussion Starter · #1 ·
Hi

I've received the following code:

1 Fault Found:
000372 - Fuel Trim; Bank 2
P0174 - 001 - System Too Lean - Intermittent


I've cleaned both MAF sensors with MAF Sensor Cleaner from CRC and swapped them from Bank 1 to Bank 2. After a couple of drives, the code returned on Bank 2 again. This should rule out issue with MAF sensor. I'm thinking there must be a vacuum leak somewhere. However, wouldn't that generate a Evap code?

I have constructed a smoke test apparatus (small air compressor, propane regulator to keep pressure at 1 psi, in-out vacuum hose running to/from container with dry ice for smoke etc).

Where would be the best point to inject my smoke into the vacuum system?
 

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You are running lean on both banks, you are just over the 20% threshold on 2 hence the fault code!

Don't drive it!

Reset the adaptions by erasing the fault memories in both ecu's then monitor 33 again (short trim and watch them climb).

If they do, you either have low low pressure circuit fuel pressure or a pretty big air leak.

If you had an air leak through, when you blip the engine it will take ages for the rpm to drop again.

Can you hear an air leak? Anything been done recently?

Cheers Ricky
 

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Ricky, I have somehow similar problem when I blip from 3 gear to 2 gear and slow down quickly the RPM should be between 3k and 2k but the RPM drop all the way below 1k then goes up to 2.5k.
what do you think the cause.
 

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yes my car tuned ECU and TCU. Transmission R-tronic.
Also, my car now with dealer they doing carbon cleaning as what super car of london did in his R8.
youtube link : https://www.youtube.com/watch?v=SDMJQjTx3eU

Do you think that will help.
 

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Not with the running lean issue, but it won't do any harm to engine performance.

Your running lean issue is either air leak or fuel pressure related to be applicable to both banks like it is.

Cheers Ricky
 

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Discussion Starter · #10 ·
Thank you for your input. I've been away traveling for work so I have not had a chance to spend more time on trouble shooting the issue. The RPMs do not drop quickly all the way down when I shift to Neutral ( I have a manual transmission ). There is some delay ...2 or 3 seconds around 2.5K RPMs as I recall.
I do not hear any loud air leak. I want to do a smoke test but I'm not sure where is the best place to inject the smoke.
 

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What was the outcome of this? I'm getting the code on my 2012 V10 (just bought a few months ago). APR tune + Fabspeed exhaust. I did not get this until after the car was tuned...but to be fair, very few miles I put on between when I bought and when it was tuned. I don't have and RPM delay issues like above that I've noticed.
 

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Have you got MAF sensors fitted in right direction and securely with no leaks?

Cheers Ricky


Sent from my iPhone using Tapatalk
 

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i just got this problem , on both bank after i put on BMC filter, everything seems to be seal, dunno if its the MAF sensor
Did you were able to resolve the issue with the BMC filters, I have the same problem after I installed the filters and the ECU /TCU update from VF Engineering. They suggest to go back to stock filters
 

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Did you were able to resolve the issue with the BMC filters, I have the same problem after I installed the filters and the ECU /TCU update from VF Engineering. They suggest to go back to stock filters
Did you revert back to stock? I have had BMC's for 2 years (10,000 miles) and no issues, now I have the 000372 Fuel Trim Bank 2. I had an EVAP Leak that was found (i watched the video) and they replaced the house by the firewall. 2 new MAF's and had them wash and re-oil the BMC's... they told me also prior to go back to OEM filters and I declined indicating that they were NOT over-oiled, rather they had not been oiled in 2 years and likely bone dry.
 

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Discussion Starter · #20 ·
Hi Pital. I've replaced the vacuum hoses running to the bypass exhaust valves. That worked for me.
 
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