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-   -   FYI, Engine Code P0171 (https://www.hummerforums.com/forum/private-sale-trade-classifieds-10/fyi-engine-code-p0171-22824/)

Major Tom Apr 22, 2011 01:21 PM

just got back from the dealer this morning, same code. Cracked vacum line

drtom Apr 22, 2011 04:28 PM

curious about vac lines,? where are they?

i dont see much compared to the old rats nest of tubing
hard to find the word in svc info

HawaiianH3 Apr 22, 2011 08:07 PM

Did they share with you which vacuum line was cracked??

Major Tom Apr 23, 2011 08:15 AM

no, I guess I should have asked. I will look and see if something looks new under the hood

Major Tom Apr 23, 2011 12:50 PM

it looks like they actally replaced the breather hose from the cold air intake to the engine. (I have a True Flow cold air intake)

Mighty455 Apr 24, 2011 07:27 AM


Originally Posted by HawaiianH3 (Post 248793)
Having the same code come up after changing my plugs, have a feeling I did not put back the intake correctly. Will keep you updated! Great post, comes up top of the list when googling Hummer H3 P0170! :cool:

Two things that I noticed when replacing my plugs with OE Iridiums that can for sure get you a vacuum leak.

1. The soft foam gasket between the fender wall and the tube that goes out to the intake. If you don"t pay attention the gasket will move out of place.

2. The hose that goes into your air intake all the way in the rear. You have to physically make sure there's a good seat on the hose to the air box or else you will also have a vacuum leak there.

BTW, My 'engine light' has never came back in the last 4 months after I added the injector cleaner mentioned in the beginning of the thread but I did replace my plugs with OE Iridiums a few weeks after adding the injector cleaner.

HawaiianH3 Apr 27, 2011 02:11 PM

My issue ended up being your #2! I have a thread on HummerXForum that depicts the spark plug replacement job. Everything I have read talks about sticking to OEM plugs. I got a great deal from Thirdflat, super cool guy! Please check out my thread.
http://http://www.hummerxclub.com/forum/viewtopic.php?f=25&t=13700

:D

Mighty455 Apr 28, 2011 07:41 AM


Originally Posted by HawaiianH3 (Post 249115)
My issue ended up being your #2! I have a thread on HummerXForum that depicts the spark plug replacement job. Everything I have read talks about sticking to OEM plugs. I got a great deal from Thirdflat, super cool guy! Please check out my thread.
http://http://www.hummerxclub.com/forum/viewtopic.php?f=25&t=13700

:D

That's great that it only ended up being the hose and not some high dollar repair. I also ended up returning the E3 spark plugs I had originally ordered and instead installed original AC Iridiums. Works like a charm, smooth and no service engine lights. Considering I have 141K it runs like new, but I also religiously put in a bottle of 'Lucas' engine treatment on every oil change for all of my cars. :cool:

garnaout Jan 17, 2012 11:32 PM

hey guys i've been reading this thread and I am having similar issues. First I thought it's the MAF being dirty as I had cleaned the K&N filter before triggering that light but then the spark plugs needed to be changed and when I did the P0171 came back again and I thought some dirt got in again but now I'm thinking it might be a vacuum leak. I am not an expert with cars so how can I check for that? how can I make sure that the mechanic replaced the spark plugs the right way?

Mannyfresh79 Jun 21, 2013 08:10 AM

Update on the engine light
 

Originally Posted by Mighty455 (Post 242151)
Hey guyz I recently purchased an H3 and the engine light was on. Went to the local Oreillys and they scanned for codes. It came up with a "P0171" which is a "system too lean (Bank 1)". I bought a bottle of "GUMOUT - Regane Fuel System Cleaner" and being that I was running a bit below a quarter of a tank I added the bottle and filled it up with premium fuel. The light had been on for a few weeks since my purchase. I went a total of about 10 miles on the way home from work and the "engine" light disappeared.

Hopefully this solves the issue. I read that cleaning the MAF sensor also helps but have not got to that point yet. I also ordered a set of E3 spark plugs and will be installing them hopefully this coming weekend.

I will update you guyz to see if this issue is fully resolved. They say fuel injector cleaners never works but I've had results go both ways. I've had it fix issues or burn out fuel pumps.

Only time will tell... :rolleyes:

Did the light came back on with the addition of gumout


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