High fuel trims? Do this!!!

[Dirtman]

For literally 3 years I've been chasing strange high fuel trims. Not high enough to set a code of effect the performance much but still enough to make me constantly suspect a vacuum leak.

I checked every way I could and never found a leak so I gave up and just accepted the fuel trims on my truck are just high for no reason. (Ltft around +12%)

Today I happened across a video about 2009+ Ford EVAP purge valve failures. Test was simple, unplug the valve and it should be 100% closed, then pull the line off going to the fuel tank and stick your finger on the nipple. If you feel suction it is leaking and therefore causing a vacuum leak...

This leak will not show up with a starting fluid test (spraying starting fluid around the engine) or even a smoke test because the leak is coming from all the way back at the fuel tank.

Sure enough mine failed the test, not a major rushing leak but definitely not sealed and enough to explain at least a slight raise in fuel trim. The computer also can't detect this leak since the computer only detects leaks when the system is purging.

So just an FYI... Applies to ALL Fords 2009+ according to the video.

 

[sgtsandman]

Fordtechmakuloco? I just saw a video he did along the lines of what you are talking about.

 

[Dirtman]

Fordtechmakuloco? I just saw a video he did along the lines of what you are talking about.

Yes him... Couldn't find the video to link it.

 

[sgtsandman]

It was about a week ago for those looking for it.

 

[sgtsandman]

 

[Dirtman]

Thanks for finding it!

 

[sgtsandman]

Thanks for finding it!

I’m subscribed to his channel, so it was easy to find.

 

[Dirtman]

I’m subscribed to his channel, so it was easy to find.

Yea him is smaht.

Threw a new purge valve on and no more leak from the fuel tank line port...

Only drove around the block but short term trims went negative so need to drive it a bit to see where it levels out on the long term trim. Leaving for Georgia in the morning so that should be enough miles to see if it fixes anything.

 

[Ranger850]

 

[Dirtman]

Well beats Florida where it's a bag of meth and a opossum carcuss...

 

[Ranger850]

More like a bag of weed and gas station hot wings

 

[Roert42]

Nothing wrong with eating opossum for dinner.

cant eat it for supper though, that’s a sin.

 

[JoshT]

So where in GA are you going to be?

 

[Dirtman]

So where in GA are you going to be?

Savannah

Good God that drive sucks, especially in a regular cab ranger. 13 hours with stopping 3 times. Once for gas, 2 to eat and toss out my pee jug...

But I averaged 29mpg on the first leg of the trip!!! Averaging 60mph using boat fuel (94 octane non ethanol) which is the best I have ever gotten by 3mpg!

Second half averaging 75mph I averaged 27mpg on e10 87 octane. I think speed had more to do with it than the fuel type. Sweet spot for fuel efficiency in my truck seems to be 55-60 mph

Both are improvements so definitely think the new purge valve helped. Way too tired to hook the scanner up and look at data on fuel trims etc tonight but I have a feeling things are gonna look better when I check tomorrow.

 

[PetroleumJunkie412]

Holy crap, mine is as if it's a direct vacuum leak.

I wonder if this explains why my 2011 is such a gutless slug.

Thanks dude!