Long term and short term fuel trims intake leak, low idle, improving fuel mileage. Mpg

[Burban22]

I’ve checked the intake air temp sensor and it’s correct according to my scanner. Example 50 degrees out and iat is reading 76 idling.

 

[Burban22]

Disconnected battery for an hour and now get these values.

Idle

2k rpm



3k rpm



These are all done at operating temp and in park. I’ve noticed engine vibration and feels rough at 2k rpm but smooth at all other rpm, idle. Maybe it’s the clutch fan making vibration at 2k? 1.8k rpm is smooth.

I ordered a fuel pressure gauge and found that my innova 5610 supposedly does injector balance test. Says to connect fuel pressure gauge and it tests one injector per key cycle.

 

[Burban22]

@Fless
Key on engine off 52-54
idle pressure is the same as KOEO
Blipping throttle it jumps to 60 then back to 52.

Holding at 2 or 3k rpm still settles at 52 - 54.

I did the balance test key on engine off, pulsed each injector and they all drop 4-7psi

 

[Burban22]

Also replaced purge valve. No change in ST or LT fuel trims. That tells me the old purge valve is good. Going to put 500 or more miles on it in the next few days. Will see if the fuel trims change at all.

 

[Fless]

Running fuel pressure should be in the mid 40s, around 43-45psi. Yours seem too high and you may want to check your fuel pressure regulator.

 

[BG1988]

Disconnected battery for an hour and now get these values.

Idle

2k rpm



3k rpm

These are all done at operating temp and in park. I’ve noticed engine vibration and feels rough at 2k rpm but smooth at all other rpm, idle. Maybe it’s the clutch fan making vibration at 2k? 1.8k rpm is smooth.

I ordered a fuel pressure gauge and found that my innova 5610 supposedly does injector balance test. Says to connect fuel pressure gauge and it tests one injector per key cycle.

Negative fuel trims means you have a restriction, negative means deducting fuel ... a clogged up fender intake with leaves?

I actually tested this by putting a piece of tape over the screen for the MAF sensor the fuel trims went negative -12-15 from positive 15-18.

 

[Burban22]

Negative fuel trims means you have a restriction, negative means deducting fuel ... a clogged up fender intake with leaves?

I actually tested this by putting a piece of tape over the screen for the MAF sensor the fuel trims went negative -12-15 from positive 15-18.

Fender and intake are not restricted.

It’s a afe cold air momentum intake. Filter is clean. Should be less restriction than stock air box. Maf is clean.

I just did knock sensors and intake gaskets. Never had an intake leak but rear knock sensor was full of water so it failed and started throwing a code for low voltage.

I’ll have to check fuel trims again once it’s up to operating temp.

 

[BG1988]

Fender and intake are not restricted.

It’s a afe cold air momentum intake. Filter is clean. Should be less restriction than stock air box. Maf is clean.

I just did knock sensors and intake gaskets. Never had an intake leak but rear knock sensor was full of water so it failed and started throwing a code for low voltage.

I’ll have to check fuel trims again once it’s up to operating temp.

looks like we found the issue did you connect that hose that connects to the OEM intake ?

 

[Burban22]

looks like we found the issue did you connect that hose that connects to the OEM intake ?

Everything’s connected

 

[Burban22]

Checked fuel trims again and still removing fuel, especially at idle.