So I recently bought a 2013 Sho and it has codes for both banks running lean. Checking fuel trims and short term fuel trims are very high 40% until long terms take over then longs are at 30% and shorts stay at 10%. Checked for any air leaks and can’t find any. Used brake clean while monitoring fuel trims and no change while spraying. Car does have a k&n air filter and oil catch can but that’s it. Compared low fuel pressure to a mechanical gauge and they are about the same. Car doesn’t have a maf sensor but barro,map,iat all appear to be working well. Smoked the intake system and couldn’t find any leaks. And have ran out of ideas. Anybody have any thoughts on what it could be?
P0171 and P0174
- Thread starter Bobisowsm
- Start date
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- Tags
- check engine light lean sho
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SapperSHO
New Member
I'm dealing with the exact same thing with my 2015, I've done literally everything you mentioned and still can't figure out what is going on. My ltft is about the same as yours, if you figure out anything let me know please.
CocoSho
New Member
Any update on this?
CocoSho
New Member
Subbing for same issue except I have downpipes, intake and exhaust.
Just the one bank not the other. I've replaced intake manifold gaskets, and oxygen sensor
Just the one bank not the other. I've replaced intake manifold gaskets, and oxygen sensor
CitySlicker
New Member
2015 SHO Stock. Can’t find the solution. Flipped o2 sensor 1 with bank 2 to see if the lean code would move to the other bank. No luck.
Visually inspected vacuum hoses. No leaks or hissing sounds. Sprayed starter fluid around connections with no change in RPM. Don’t know what to attack next except pulling the intake manifold off.
Visually inspected vacuum hoses. No leaks or hissing sounds. Sprayed starter fluid around connections with no change in RPM. Don’t know what to attack next except pulling the intake manifold off.
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Try these steps
CitySlicker
New Member
Kryptto,
Followed the sequence.
1. swapped o2 sensors to replicate on bank 2. (no solution)
2. Sprayed intake components with carb cleaner for idle change. (No solution)
3. inspected and cleaned map sensors with MAF cleaner. (No solution)
4. inspected and cleaned PCV valve. Insured, it "rattled" and moved freely. (No solution)
5. Ran numerous cans of fuel system cleaner. (No solution)
6. Replaced MAP sensor on top of intake manifold (No solution)
7. Inspected spark plugs for equal wear across both banks. (No indication of unequal burning)
8. Unplugged battery overnight to clear permanent code. (came back on within 24 hours.)
9. Unsuccessfully attempted smoke test. will attempt again with a shop.
Would like to check compression next as well.
Followed the sequence.
1. swapped o2 sensors to replicate on bank 2. (no solution)
2. Sprayed intake components with carb cleaner for idle change. (No solution)
3. inspected and cleaned map sensors with MAF cleaner. (No solution)
4. inspected and cleaned PCV valve. Insured, it "rattled" and moved freely. (No solution)
5. Ran numerous cans of fuel system cleaner. (No solution)
6. Replaced MAP sensor on top of intake manifold (No solution)
7. Inspected spark plugs for equal wear across both banks. (No indication of unequal burning)
8. Unplugged battery overnight to clear permanent code. (came back on within 24 hours.)
9. Unsuccessfully attempted smoke test. will attempt again with a shop.
Would like to check compression next as well.
CitySlicker
New Member
12 months ago. Problem started. Vehicle inspected at our local dealer. They said nothing was wrong, cleared code, and moved on. It happened again some months later; I had a small shop look at it, said its a dealer issue, cleared the code, and moved on. In the last 3 months it has been a consistent problem.
I want to emphasize that my local Ford dealership in Charleston, South Carolina, is terrible. They do the absolute least amount of work for the most amount of money. They are always backlogged. I am sure they didn't see enough money in my issue and sent me on my way.
I want to emphasize that my local Ford dealership in Charleston, South Carolina, is terrible. They do the absolute least amount of work for the most amount of money. They are always backlogged. I am sure they didn't see enough money in my issue and sent me on my way.
CitySlicker
New Member
The shop said it's a dealer issue, I believe, because they don't prefer working on these cars. I don't think it was in ill intent. I have used the shop for older vehicles in the past.
This is why I have taken it upon myself to fix the issue.
Does it run poorly? Can you read the fuel pressure with your scanner (high pressure and low pressure pumps)? An engine can also indicate running lean because it can't get enough fuel. If your low pressure fuel pump is good then you'd monitor the high pressure fuel pump (HPFP) duty cycle to see what the ECU is calling for (at idle and WOT). If too high for conditions, then fuel pump would be suspect. You have a fuel/air mixture problem that is is effecting both banks. That indicates a common vacuum leak or a common fuel supply issue (one of the pumps).
CitySlicker
New Member
I will get this data and report back. I will get the engine temp as well. From what I see on the internet the fuel pressure to the engine should be around 72 PSI
CitySlicker
New Member
Bradm,
Unable to get those answers. The Fuel pressure at the rail was the only finding avalible. however @kryptto troubleshooting sheet suggests it is a vacuum leak.
Unable to get those answers. The Fuel pressure at the rail was the only finding avalible. however @kryptto troubleshooting sheet suggests it is a vacuum leak.
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