Running lean bank 1 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


Buick When starting new posts, please specify YEAR, MAKE, MODEL, ENGINE type, and whatever modifications you have made.

Reply
 
 
 
Thread Tools Search this Thread
Old 06-26-2014, 04:00 PM   #1
Junior Member
Posts like a V-Tak
Thread Starter
 
Join Date: Jun 2014
Location: Paducah Ky
Posts: 29
Thanked 0 Times in 0 Posts
stevegs59 is on a distinguished road
Default Running lean bank 1

Ok, next problem. Check engine light came back on. Had Autozone read the code. Code says running lean bank 1. Offers possible problems. Only thing I haven't changed is the o2 sensor. Think that'* the problem?
stevegs59 is offline   Reply With Quote
Old 06-26-2014, 04:10 PM   #2
Senior Member
True Car Nut
 
jwfirebird's Avatar
 
Join Date: Dec 2009
Location: western,ny state
Posts: 9,616
Thanked 563 Times in 481 Posts
jwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond repute
Default

very rarely is it the o2 when you have lean codes.they have there own codes
jwfirebird is offline   Reply With Quote
Old 06-26-2014, 04:12 PM   #3
Senior Member
True Car Nut
 
jwfirebird's Avatar
 
Join Date: Dec 2009
Location: western,ny state
Posts: 9,616
Thanked 563 Times in 481 Posts
jwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond repute
Default

you check fuel pressure now with the new battery?
jwfirebird is offline   Reply With Quote
Old 06-26-2014, 04:23 PM   #4
Senior Administrator








Certified Car Nut
 
Mike's Avatar
 
Join Date: Jul 2003
Location: Horseheads, NY
Posts: 15,643
Thanked 997 Times in 774 Posts
Mike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond repute
Default

Whoa,, let'* keep one issue per thread please. This is to prevent confusion in the future and long page reads.
Mike is offline   Reply With Quote
Old 06-26-2014, 04:35 PM   #5
Junior Member
Posts like a V-Tak
Thread Starter
 
Join Date: Jun 2014
Location: Paducah Ky
Posts: 29
Thanked 0 Times in 0 Posts
stevegs59 is on a distinguished road
Default

JW, It has thrown this code for quite some time now. Any suggestions? Car has 180+++ miles
stevegs59 is offline   Reply With Quote
Old 06-26-2014, 04:56 PM   #6
Senior Member
True Car Nut
 
jwfirebird's Avatar
 
Join Date: Dec 2009
Location: western,ny state
Posts: 9,616
Thanked 563 Times in 481 Posts
jwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond reputejwfirebird has a reputation beyond repute
Default

lean codes are tough. the first thing is verify fuel pressure. then most common is vacuum leaks, there are very many places it could, the 3800 has a common place that is the boot that feeds the evap and fpr. the boot gets heat soaked from the engine cover and looks dry rotted if so replace it and the lines to the fpr/purge solenoid.
jwfirebird is offline   Reply With Quote
The Following User Says Thank You to jwfirebird For This Useful Post:
stevegs59 (06-26-2014)
Old 06-27-2014, 07:53 AM   #7
Senior Member

Certified GM nut
 
Tech II's Avatar
 
Join Date: Feb 2014
Location: Worcester, Ma.
Posts: 2,143
Thanked 780 Times in 609 Posts
Tech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond repute
Default

Code says running lean bank 1

Technically, there is no such thing, since you only have one O2 sensor for fuel management...that O2 sensor is affected by both banks.....

could be any number of things....I doubt fuel pressure if it is running ok....like the guys said, could be a vac leak.....could even be an exhaust leak at the doughnut of the ex manifold......could even be a bad MAF(you would need a scan tool to see this, by watching O2 data while disconnecting the MAF).....could be a bad O2 sensor(could also be contaminated, coolant or carbon), but you should create a lean/rich condition and watch O2 sensor, to see if it responds....
Tech II is offline   Reply With Quote
The Following User Says Thank You to Tech II For This Useful Post:
stevegs59 (06-27-2014)
Old 06-27-2014, 09:20 AM   #8
Junior Member
Posts like a V-Tak
Thread Starter
 
Join Date: Jun 2014
Location: Paducah Ky
Posts: 29
Thanked 0 Times in 0 Posts
stevegs59 is on a distinguished road
Default

Well, thanks for the info. Sounds more complicated than I can do. Have replaced MAF sensor, and apparently it was not the problem.
stevegs59 is offline   Reply With Quote
Old 06-27-2014, 09:30 PM   #9
Senior Administrator








Certified Car Nut
 
Mike's Avatar
 
Join Date: Jul 2003
Location: Horseheads, NY
Posts: 15,643
Thanked 997 Times in 774 Posts
Mike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond repute
Default

Quote:
Originally Posted by Tech II View Post
Code says running lean bank 1

Technically, there is no such thing, since you only have one O2 sensor for fuel management...that O2 sensor is affected by both banks.....
Actually, the PCM can differentiate between both banks via 1 sensor. It adjusts fueling between the banks and watches the O2 for any changes. This is how it knows which bank it is. Same thing with knock sensors, on a V8, a computer using 1 knock sensor can pinpoint which cylinder is misfiring.

In his case, the rear bank injectors are getting most of the fuel(due to the **** poor design of the fuel rail) and the front bank(or bank 1) is getting the least amount of fuel. So in his case, a weak fuel pump/or low voltage at the pump can cause him to have a lean bank condition.
Mike is offline   Reply With Quote
The Following User Says Thank You to Mike For This Useful Post:
stevegs59 (06-27-2014)
Old 06-28-2014, 04:15 PM   #10
Senior Member

Certified GM nut
 
Tech II's Avatar
 
Join Date: Feb 2014
Location: Worcester, Ma.
Posts: 2,143
Thanked 780 Times in 609 Posts
Tech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond reputeTech II has a reputation beyond repute
Default

Actually, the PCM can differentiate between both banks via 1 sensor. It adjusts fueling between the banks and watches the O2 for any changes. This is how it knows which bank it is. Same thing with knock sensors, on a V8, a computer using 1 knock sensor can pinpoint which cylinder is misfiring.

You may be right Mike, but I don't think the PCM is set up to do that......looking through a manual, I see P0171 ......I do not see P0174 for this vehicle....I think you need O2Bank2sensor1 for that code, and to be able to differentiate which bank is running lean........

In his case, the rear bank injectors are getting most of the fuel(due to the **** poor design of the fuel rail) and the front bank(or bank 1) is getting the least amount of fuel. So in his case, a weak fuel pump/or low voltage at the pump can cause him to have a lean bank condition.

I wonder about that.....has anyone ever installed a fuel gauge just before the rail and also at the schraeder, to see how much of a difference in fuel pressure, there actually is? A fully functioning fuel pump doesn't set a code for a lean bank, so if you have low voltage or weak fuel pump, the drop in pressure will be proportional to both sides, and won't register as one bank being leaner than the other....of, course I could be wrong......
Tech II is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
PO171, "Bank 1 lean?" Bob Dillon 1992-1999 9 01-27-2007 12:20 PM
"Lean Fuel Bank One - Help!" SOLVED San Juan Cruiser 2000-2005 67 06-08-2006 10:05 AM
Can a dying battery cause a bank of cyl to run lean? ELMACHOGERACHO 1992-1999 7 11-04-2005 03:01 PM
HELP! had the code PO171 show up (fuel system lean bank 1) marksssei 1992-1999 2 07-19-2004 06:38 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 10:43 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.