NAIOA.comNAIOA.comNAIOA.com
 Create an Account
 

  
NAIOA Impala Forums :: View topic - Low Gas Mileage
GarageGarage    1/4 Mile Table1/4 Mile Table    Forum FAQForum FAQ    SearchSearch    UsergroupsUsergroups   MedalsMedals
MemberlistMemberlist   ProfileProfile    Watched TopicsWatched Topics    Log in to check your private messagesLog in to check your private messages    Log inLog in 

Low Gas Mileage

 
Post new topic   Reply to topic    NAIOA Impala Forums Forum Index -> Problems with my car!
View previous topic :: View next topic  
Author Message
craig
Newbie
Newbie


Joined: Jun 26, 2011
Posts: 3
Posts per day: 0



PostPosted: Sat Jul 23, 2011 12:22 pm    Post subject:  Low Gas Mileage Reply with quote

2001 LS with 80k miles.
I am getting worse mileage than usual (~20%), so I hooked up a fancy scanner and got these values.

Ignition Advance (deg): 19.5-22.5

TPS = 0.3 (at idle)

Calc Load % = 1.9

MAF = 3.91-4.2 grams/sec

MAP = 31-32 KPa

Coolant Temp after 5-6 min idling = 192

IAT started at 166, went up to 118, eventually went down to 107 with ambient temp probably around 75 outside

O2S11 ranged between 0.095V to 0.85V, changing every few seconds

Short Term Fuel Trim from -1% to +0.8%

Long Term Fuel Trim always steady at 0.0%

I was worried about the LTFT begin 0 on a 10 year old car, seems like that would not be possible. Also curious about the Intake Air Temp as the car had been sitting for a few hours and it was about 75 degrees outside.
Back to top
View user's profile Send private message
Pitch Black SS
NAIOA Owner / Founder
NAIOA Administrator
NAIOA Administrator


Joined: Mar 08, 2004
Posts: 12756
Posts per day: 2.58
Location: Tullahoma, TN

2004 Chevrolet Impala
1982 Chevrolet Malibu
2007 Chrysler 300C
1986 Chevrolet Monte Carlo


PostPosted: Sat Jul 23, 2011 3:18 pm    Post subject:   Reply with quote

the IAT is probably high if you had the car sitting there at idle while testing. The intake tube and filter housing will soak up engine bay heat causing the IAT to go up.

_________________
Back to top
View user's profile Send private message Visit poster's website AIM Address
IffyG
NAIOA Moderator
NAIOA Moderator
Silver Contributor (Amount: 1) Silver Contributor


Joined: May 19, 2007
Posts: 13731
Posts per day: 3.63
Location: Nashville, TN

2002 Chevrolet Monte Carlo
1998 Oldsmobile Intrigue
2009 Chevrolet Malibu


PostPosted: Sat Jul 23, 2011 9:31 pm    Post subject:   Reply with quote

What exactly were you using to log. From what I've read, you need to take the fuel trims with a grain of salt unless you are using a full blown scanning tool program.

_________________
helldorado wrote:
GLWTGFY. Big Thumbs Up

Dan wrote:
Protip: If you don't know what you're doing, don't do it.


d
Back to top
View user's profile Send private message
98ss
Uber
Uber


Joined: Jun 06, 2009
Posts: 817
Posts per day: 0.27
Location: Ann Arbor

2002 Chevrolet Impala
2011 Chevrolet Silverado


PostPosted: Sun Jul 24, 2011 7:12 am    Post subject:   Reply with quote

IffyG wrote:
What exactly were you using to log. From what I've read, you need to take the fuel trims with a grain of salt unless you are using a full blown scanning tool program.


2 car guys show, on speed did a show on that, they had to graph the 02 sensors ect. I have an innovate, and I can watch stuff switch, but in reality 02 sensors ect are switching at a much faster rate.

When my CAT started to go, my mileage went to crap.

Edit: but it could be lazy 02 sensors, lower intake, or could be something really simple like a fuel filter, or a combo.
Back to top
View user's profile Send private message
craig
Newbie
Newbie


Joined: Jun 26, 2011
Posts: 3
Posts per day: 0



PostPosted: Sun Jul 24, 2011 9:36 am    Post subject:   Reply with quote

Pitch Black SS wrote:
the IAT is probably high if you had the car sitting there at idle while testing. The intake tube and filter housing will soak up engine bay heat causing the IAT to go up.


i might just put a new one in and see because it looks fairly easy and cheap.

IffyG wrote:
What exactly were you using to log. From what I've read, you need to take the fuel trims with a grain of salt unless you are using a full blown scanning tool program.


my friends handheld scanner. it gives "live" values of the measurements i listed

98ss wrote:
Edit: but it could be lazy 02 sensors, lower intake, or could be something really simple like a fuel filter, or a combo.


I did have to have the cat replaced a couple years back. It was really strange but the car would almost redline the rpm's before changing gears. turned out to be a blocked cat. did get that one done for free due to exhaust warranty.

Overall I am thinking of changing the fuel filter, O2 sensors and the IAT sensor. Will post back when I can finally get to it.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    NAIOA Impala Forums Forum Index -> Problems with my car! All times are GMT - 4 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

Powered by phpBB © 2001, 2005 phpBB Group
Forums ©
All logos and trademarks in this site are property of their respective owner. Comments and posts are property of the poster. All other content is © 2008 by the NAIOA.


Use of this site constitutes agreement with the NAIOA Terms of Service (TOS)


PHP-Nuke Copyright © 2005 by Francisco Burzi. This is free software, and you may redistribute it under the GPL. PHP-Nuke comes with absolutely no warranty, for details, see the license.
Server Local Time: September 24, 2017, 5:31:14 am
Page Generation: 0.09 Seconds ( SQL 25:110 in 0.01 Seconds )