Running Lean
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Tuned
Joined: Jul 2009
Posts: 258
Likes: 18
From: mid-nowhere AZ desert
Running Lean
1997 F350 CC 4x4 California Emissions OBDII 7.5L gas (hog)
My truck showed a code for lean Bank1, Lean Bank 2.
I erased the codes to see if they would return. Did in about 25 miles.
Looked at live data on the code reader,
STFT was about 6 (idyl), LTFT was near +11.
Cleared the code again, hasn't returned.
I cleaned the MAF (looked very clean)
Ran it again for live data, both banks varies from + 10 to +12 LTFT running down the road 1500 - 2000 rpm.
Changed fuel tanks to see if it might be low fuel pressure from one of the tank pumps, no difference from tank to tank.
As far as I understand , this is still pretty lean, but doesn't throw a code or CEL.
Anyone know what LTFT I should be seeing? (0?)
Anyone know what the limit is that sets the code and CEL?
My truck showed a code for lean Bank1, Lean Bank 2.
I erased the codes to see if they would return. Did in about 25 miles.
Looked at live data on the code reader,
STFT was about 6 (idyl), LTFT was near +11.
Cleared the code again, hasn't returned.
I cleaned the MAF (looked very clean)
Ran it again for live data, both banks varies from + 10 to +12 LTFT running down the road 1500 - 2000 rpm.
Changed fuel tanks to see if it might be low fuel pressure from one of the tank pumps, no difference from tank to tank.
As far as I understand , this is still pretty lean, but doesn't throw a code or CEL.
Anyone know what LTFT I should be seeing? (0?)
Anyone know what the limit is that sets the code and CEL?
Fleet Mechanic
Joined: Feb 2007
Posts: 1,652
Likes: 79
From: Mooresville, NC
1997 F350 CC 4x4 California Emissions OBDII 7.5L gas (hog)
My truck showed a code for lean Bank1, Lean Bank 2.
I erased the codes to see if they would return. Did in about 25 miles.
Looked at live data on the code reader,
STFT was about 6 (idyl), LTFT was near +11.
Cleared the code again, hasn't returned.
I cleaned the MAF (looked very clean)
Ran it again for live data, both banks varies from + 10 to +12 LTFT running down the road 1500 - 2000 rpm.
Changed fuel tanks to see if it might be low fuel pressure from one of the tank pumps, no difference from tank to tank.
As far as I understand , this is still pretty lean, but doesn't throw a code or CEL.
Anyone know what LTFT I should be seeing? (0?)
Anyone know what the limit is that sets the code and CEL?
My truck showed a code for lean Bank1, Lean Bank 2.
I erased the codes to see if they would return. Did in about 25 miles.
Looked at live data on the code reader,
STFT was about 6 (idyl), LTFT was near +11.
Cleared the code again, hasn't returned.
I cleaned the MAF (looked very clean)
Ran it again for live data, both banks varies from + 10 to +12 LTFT running down the road 1500 - 2000 rpm.
Changed fuel tanks to see if it might be low fuel pressure from one of the tank pumps, no difference from tank to tank.
As far as I understand , this is still pretty lean, but doesn't throw a code or CEL.
Anyone know what LTFT I should be seeing? (0?)
Anyone know what the limit is that sets the code and CEL?
"0" is considered "perfect" balance on the trims. Did you get a number of fuel psi (switching between tanks only isolates some of the causes)?
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
+10 to +12 is rich isn't it, meaning the computer thinks the motor is lean so its adding extra fuel. If your driving around milage really sucks more than usual for a 460 then that would seem to confirm this. Possible causes are exhaust leaks upstream of the O2 sensor, leaks in the thermactor(air injection) system, tired O2 sensor/s, or maybe a crack in the EGR tube allowing fresh air into the motor.
Thread Starter
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Tuned
Joined: Jul 2009
Posts: 258
Likes: 18
From: mid-nowhere AZ desert
[quote ="0" is considered "perfect" balance on the trims. Did you get a number of fuel psi (switching between tanks only isolates some of the causes)?]
Need to put a gauge on it to see, but wouldn't think both pumps would come up weak at the same (has recent filter)
Don't drive it enough to tell on on the fuel mileage. Has no thermactor, wouldn't think both O2 sensors would fail equally.
Need to check EGR and Exhaust leak (but again both sides at once?) as it has different code for bank one and bank 2, and both hit at the same time.
Thanks for the suggestions, guys!
Need to put a gauge on it to see, but wouldn't think both pumps would come up weak at the same (has recent filter)
+10 to +12 is rich isn't it, meaning the computer thinks the motor is lean so its adding extra fuel. If your driving around milage really sucks more than usual for a 460 then that would seem to confirm this. Possible causes are exhaust leaks upstream of the O2 sensor, leaks in the thermactor(air injection) system, tired O2 sensor/s, or maybe a crack in the EGR tube allowing fresh air into the motor.
Need to check EGR and Exhaust leak (but again both sides at once?) as it has different code for bank one and bank 2, and both hit at the same time.
Thanks for the suggestions, guys!
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