• Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.

Long Term Fuel Trim Bank 1 drops to 0 at idle, or foot off gas pedal.


bills4065

Member
Canada Military - Veteran
Joined
Apr 1, 2021
Messages
37
Reaction score
9
Points
8
Location
Dartmouth Nova Scotia Canada
Vehicle Year
2007
Make / Model
Ford Ranger
Engine Type
3.0 V6
Transmission
Manual
2WD / 4WD
2WD
Idle Readings: LTFT1 - negative .8, LTFT2 is 10.9, STFT1 negative .8, STFT2 negative .8 When you push down on the gas pedal driving LTFT1-6.3% LTFT2 is 8.6% STFT1 is 3.1% STFT2 is 4.7% When you let off on gas pedal or sitting with truck in park idling , the Long Term Fuel Trim Bank 1 drops to negative .8 %. Any one ever seen either of the long term fuel trim banks drop to 0 on taking foot off the gas, or sitting idling. 2008 V6 automatic transmission.
 


franklin2

Well-Known Member
Joined
Dec 24, 2019
Messages
3,467
Reaction score
1,781
Points
113
Location
Virginia
Vehicle Year
1984
Make / Model
Bronco II
Transmission
Manual
On fuel trims I thought zero was perfect, and the further away from zero you got, more likely you have a potential problem. They say in this article I found it usually has to get to 25% before the check engine light will light up.

 

bills4065

Member
Canada Military - Veteran
Joined
Apr 1, 2021
Messages
37
Reaction score
9
Points
8
Location
Dartmouth Nova Scotia Canada
Vehicle Year
2007
Make / Model
Ford Ranger
Engine Type
3.0 V6
Transmission
Manual
2WD / 4WD
2WD
@franklin2, great article Thank you for sharing. This is a friends Ranger, he asked me to scan it for him. Long terms Bank 1 and Bank 2 seem to be within specs when driving the vehicle. It is just if you take foot off the gas pedal, or are sitting at idle . Long term Fuel Trim bank 1 drops to negative .8% Long term fuel Trim Bank number 2 stays at around 9%. It seems too me that LTFT bank # 1 is not learning, that is just a guess on my behalf. He sad truck has gotten a lot harder on fuel. I know my own ranger, the LTFTs change , but they are within a couple % of each other.
 

bills4065

Member
Canada Military - Veteran
Joined
Apr 1, 2021
Messages
37
Reaction score
9
Points
8
Location
Dartmouth Nova Scotia Canada
Vehicle Year
2007
Make / Model
Ford Ranger
Engine Type
3.0 V6
Transmission
Manual
2WD / 4WD
2WD
If anyone is interested, this vehicle would have been too expensive to have rust repairs carried out, would have been more than vehicle value. He did donate it to automotive training campus , were automotive instructor and students used this as training. The instructor did call him and inform him this ranger had a restricted exhaust on bank # 1. Just a note of interest, I contacted the instructor at this trade school. He said they use James Halderman engine diagnostics books for training students. There is a You Tube video on this: Fuel Trim Imbalance case study presented by John Thornton. Gets quite technical in the video.
 
Last edited:

alwaysFlOoReD

Forum Staff Member
TRS Forum Moderator
TRS Banner 2012-2015
TRS 20th Anniversary
Joined
Apr 13, 2009
Messages
14,009
Reaction score
5,179
Points
113
Location
Calgary, Canada
Vehicle Year
'91, '80, '06
Make / Model
Ford, GMC,Dodge
Engine Size
4.0,4.0,5.7
Transmission
Manual
2WD / 4WD
4WD
If anyone is interested, this vehicle would have been too expensive to have rust repairs carried out, would have been more than vehicle value. He did donate it to automotive training campus , were automotive instructor and students used this as training. The instructor did call him and inform him this ranger had a restricted exhaust on bank # 1.
Thanks for the update.
 

Sponsored Ad


Sponsored Ad

Staff online

Member & Vendor Upgrades

For a small yearly donation, you can support this forum and receive a 'Supporting Member' banner, or become a 'Supporting Vendor' and promote your products here. Click the banner to find out how.

Truck of The Month


Mudtruggy
May Truck of The Month

Recently Featured

Want to see your truck here? Share your photos and details in the forum.

Follow TRS On Instagram

TRS Events

25th Anniversary Sponsors

Check Out The TRS Store


Sponsored Ad


Sponsored Ad

Sponsored Ad


Amazon Deals

Top