Fuels being run - BG question

[dpigguy]

I have been working with BG testing fuels in my '08 C6 to see if there is a relationship to the "false" CEL codes I have recorded over 7 times in 3000 miles. I am in Texas and have so far documented similar issues in Arizona. Can you post a reply with the brand of fuel you are using, state location, and whether or not you have had CEL issues with codes P0171 and P0174? Thanks in advance - I will follow up with any conclusions reached.

 

[Patrick]

Dpigguy,
Here's hoping this helps with your research.

I live in Colorado (Denver metro area), and routinely use either Shell (91 Octane with V-Power) or Conoco/Phillips 66. All of these are 'Top Tier' gas retailers, and 91 Octane is the highest you can get in Colorado.

I don't know if this will be of any use to you, but assuming the codes on a C6 are similar to those of a C5, the P0171 and P0174 refer to these:

P0171 Fuel Trim System Lean Bank 1
P0174 Fuel Trim System Lean Bank 2

I used to occasionally get those on my '03 Z06, and the reason appeared to be down to an MAF sensor which would occasionally come loose.

-Patrick

 

[dpigguy]

Dpigguy,
Here's hoping this helps with your research.

I live in Colorado (Denver metro area), and routinely use either Shell (91 Octane with V-Power) or Conoco/Phillips 66. All of these are 'Top Tier' gas retailers, and 91 Octane is the highest you can get in Colorado.

I don't know if this will be of any use to you, but assuming the codes on a C6 are similar to those of a C5, the P0171 and P0174 refer to these:

P0171 Fuel Trim System Lean Bank 1
P0174 Fuel Trim System Lean Bank 2

I used to occasionally get those on my '03 Z06, and the reason appeared to be down to an MAF sensor which would occasionally come loose.

-Patrick

thanks Patrick - I have received a bunch of input on another forum and will adds yours to the list. the codes are the same and it does appear that top-tier fuel does make a difference. will post all results once I have them.

 

[LittleRedFlatBack]

I have been working with BG testing fuels in my '08 C6 to see if there is a relationship to the "false" CEL codes I have recorded over 7 times in 3000 miles. I am in Texas and have so far documented similar issues in Arizona. Can you post a reply with the brand of fuel you are using, state location, and whether or not you have had CEL issues with codes P0171 and P0174? Thanks in advance - I will follow up with any conclusions reached.

I'm from the Houston, Texas area (south side) and usually use Shell, Exxon, Mobil or Chevron (Premium gas) and I've never had any CEL issues. I've only owned the C5 for three months now, but I used the same gas in my C4 prior to that. Hope this helps.

 

[Tuna]

I'm in Oklahoma City area and generally run Wal-Mart or Sams gas (Murphy Oil) in all my cars. No problems noted with either the '06 or '08.

 

[c4c5specialist]

HI there,
Just remember, depending on alcohol content, this could also be an issue.
Im very surprised noone suggested taking a check on this.
My customers develop issues when running the cheap fuels from wholesale clubs and grocery stores.
Top tier fuels usually reduce the amount of fuel system concerns substantially.
Allthebest, c4c5

 

[SpryGeezer]

No problems using only Chevron 91 in my '07 A6 coupe in ABQ NM at 5000-7000ft.

 

[avacorvette]

Dpigguy,
Here's hoping this helps with your research.

I live in Colorado (Denver metro area), and routinely use either Shell (91 Octane with V-Power) or Conoco/Phillips 66. All of these are 'Top Tier' gas retailers, and 91 Octane is the highest you can get in Colorado.

I don't know if this will be of any use to you, but assuming the codes on a C6 are similar to those of a C5, the P0171 and P0174 refer to these:

P0171 Fuel Trim System Lean Bank 1
P0174 Fuel Trim System Lean Bank 2

I used to occasionally get those on my '03 Z06, and the reason appeared to be down to an MAF sensor which would occasionally come loose.

-Patrick

I see that Shell is only a top tier gas in Canada. Here in the PA they use 10% alcohol in Shell gas. I have not bought Shell for the last 3 years cause they dropped their 96 octane to 93 and put in alcohol .

 

[littlejohn]

P0171 and P0174

I live in AZ and also get the P0171 & P0174 codes popping up. I changed my Throttle body gasket, rechecked elect connections, reinstalled my air bridge and I still get the codes. I did notice that when I use only Chevron gas (91%) the codes are less seldom. If I use Shell, within 5 miles I get the codes. I'm thinking that it could either be the gas (unlikely because I still get codes, only less seldom) or maybe my MAF senor. Anyone have any ideas?

 

[dpigguy]

The CEL issue I have been chasing is on the LS3. I see you have a '04 Z06. Only suggestion other then fuel switch (which seems to have worked for me) is to check the two panels that come together below the air filter element in the snorkel. Here's what the folks in BG had me check:

"One area we have found that makes a difference is the sealing of panels below the air cleaner inlet. To check, remove the air cleaner inlet. It will require you to loosen the band where it meets the engine intake, disconnect the wire at the sender on the air intake snorkel. Lift the air cleaner snorkel off the mounting pins. Look at the area where the inlet of the air cleaner opening wold normally be. There are two panels that come together and they should not be a gap between them. If a curb has rubber the lower air dam or it was not installed correctly it can allow additional air to enter the air cleaner that is not accounted for. This can create a turbulence in the snorkel and cause the readings across the air flow sender to fluctuate more than our calibration will allow."

The band on this end must loosened to
remove the air cleaner and snorkel

This end is pointed down

A gap between the bottom deflector shield and the front frame plate and/or the mounting holes found on the frame plate may be affecting the airflow across the MAF sensor.

The air box is removed in this photo

It is suggested:
1. Inspect for a gap as note above and make sure the gap is closed and stays closed.
2. Using a HVAC metal tape cover the mounting holes on the frame plate.
3.if you find any space between the panels, tape over same using a HVAC metal type tape.

Sorry about the long message but maybe this will help. I found a space and fixed it as instructed in this information.

Dan

 

[JBsC5]

Shell high test

Citicard offers a 5% rebate back on all the gas you buy at shell stations if you get a shell citicard.

Not a bad program..

No problems with the car running on this fuel..

 

[dpigguy]

update survey results

In March I asked for input on fuels used as part of a question I was trying to answer for BG. Concern was 2008 cars that experienced multiple CEL warnings since purchase. BG engineers were suspect that fuels being used were the cause for the CEL warnings. Here's what I found out from this and other forum member input:

I received input from 17 owners of 2008 vehicles. Of those, 5 (29.4%) had experienced multiple CEL warnings that could not be resolved. Of the 5 impacted vehicles, 4 (80%) were running Shell 93 octane with the remaining vehicle running ExxonMobil. BG recommends top-tier fuels only of which Shell is one but XOM is not. Subsequently, the vehicle running XOM switched to Chevron which cured the issue.

There was no clear geographic correlation with events happening in AZ, TX, IL, NJ and New York. Of those vehicles which had not seen the CEL, all were running top tier fuels including some Shell but none were in the same areas as those who experienced the issue. BG is still working on a programming fix but my results would say top tier fuel is important and a switch to another top tier fuel in those vehicles having the issue may be a quick solution.

Something else to think about! Thanks to those who responded!