AFR Jumps way high in boost - Cobalt SS Network

Go Back  Cobalt SS Network > General > Problems/Service/Maintenance
AFR Jumps way high in boost >

AFR Jumps way high in boost

Problems/Service/Maintenance Do you have problems with your new 2.0, 2.2, or 2.4L? What kind of service did you have done?

AFR Jumps way high in boost


Old 12-07-2018, 09:06 PM
New Member
Thread Starter
Join Date: 12-07-18
Location: Wisconsin
Posts: 1
Thanked 0 Times in 0 Posts
Exclamation AFR Jumps way high in boost

Hi I own a 2008 Cobalt SS/TC on E85. I bought the car on Craigslist and supposedly it is tuned for 25psi and E85 and has the upgraded fuel pump and injectors and all of that.

When I go into boost suddenly or aggressively the afr jumps really high (~29) im not sure if itís a sensor problem or if Iím maxing anything out while doing so? If I ease into boost the afrs seem to be fine but again Iím not sure. (Iíve had the car for months and have driven it at WOT multiple times but I just programmed the gauge for AFR and Iím surprised it hasnít blown up yet? Thanks for any info
Bigboybalt is offline  
Reply With Quote
Old 12-08-2018, 08:52 AM
Senior Member
iTrader: (3)
Join Date: 06-13-12
Location: Indiana
Posts: 4,983
Thanked 249 Times in 234 Posts
Yeah that's pretty scary. You need to check that out. 29 is what it should read when the fuel shuts off after you let off the throttle and the injectors shut off.
63 Nova SS is offline  
Reply With Quote
The Following User Says Thank You to 63 Nova SS For This Useful Post:
Bigboybalt (12-08-2018)
Old 12-11-2018, 09:07 PM
Super Moderator
Platinum Member
iTrader: (2)
Join Date: 07-14-08
Location: canada
Posts: 11,728
Thanked 103 Times in 93 Posts
are you sure its not between shifts or when u take ur foot off the gas suddenly? cause that would be normal. if its doing it when ur on the gas, ur going super lean and u need to stop it now and get someone to check ur tune
tomj77 is offline  
Reply With Quote
Old 12-11-2018, 10:57 PM
New Member
Join Date: 10-21-18
Location: CA
Posts: 13
Thanked 0 Times in 0 Posts
With a 29:1 AFR under throttle, the fuel mixture is too lean to support combustion. That will result in misfire on all 4 cylinders and a loss of all power and boost. If the engine is running normally and it's still showing 29:1, you have something else going on.
Sport Red LNF is offline  
Reply With Quote
Related Topics
Thread Starter
Last Post
Jeffs 06SS 2.4
01-03-2010 05:59 PM
The Lounge
11-06-2008 01:17 AM
08-08-2008 07:01 PM
08-04-2007 07:37 PM
The Lounge
11-28-2006 11:02 AM

Thread Tools
Search this Thread
Quick Reply: AFR Jumps way high in boost

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

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 and affiliated sites.