strange LTFT

[bee_are_zee]

I am having some very strange issue with my LTFT at idle. A little background, I am running a vortech supercharger with an OFT tune, 9psi pulley, stock injectors. When I first turn the car on it is in injector mode 1 (port only) and the fuel trims will climb until maxed out at 39.4%. If i blip the throttle a few times the idle will switch to mode 2 (DI only) and will idle fine. normal driving conditions seem to be fine as well. Any thoughts as to what could be causing this?

I have already checked for vacuum leaks or any exhaust gasket leaks.

[steve99]

Originally Posted by bee_are_zee

I am having some very strange issue with my LTFT at idle. A little background, I am running a vortech supercharger with an OFT tune, 9psi pulley, stock injectors. When I first turn the car on it is in injector mode 1 (port only) and the fuel trims will climb until maxed out at 39.4%. If i blip the throttle a few times the idle will switch to mode 2 (DI only) and will idle fine. normal driving conditions seem to be fine as well. Any thoughts as to what could be causing this?

I have already checked for vacuum leaks or any exhaust gasket leaks.

sounds weird, id talk to the tuner, also check for exhaust or intake leaks

[clayrush]

I recently had a problem with my STFT at idle. It was max because a o ring poped on my port injector fuel pump, causing it to leak back into my gas tank. Idle was crap as well. It was on a DW pump

[bee_are_zee]

Originally Posted by clayrush

I recently had a problem with my STFT at idle. It was max because a o ring poped on my port injector fuel pump, causing it to leak back into my gas tank. Idle was crap as well. It was on a DW pump

I'm between bad injector or in tank pump. Were you able to log a low fuel pressure before you pulled the pump?

[FRS Justin]

Originally Posted by bee_are_zee

I am having some very strange issue with my LTFT at idle. A little background, I am running a vortech supercharger with an OFT tune, 9psi pulley, stock injectors. When I first turn the car on it is in injector mode 1 (port only) and the fuel trims will climb until maxed out at 39.4%. If i blip the throttle a few times the idle will switch to mode 2 (DI only) and will idle fine. normal driving conditions seem to be fine as well. Any thoughts as to what could be causing this?

I have already checked for vacuum leaks or any exhaust gasket leaks.

This sounds like a fuel pressure problem or a bad Injector.

If you do not have the correct fuel pressure it will cause a rich or lean condition. Example low fuel pump output would cause a low pressure not allowing the injector to spray the given volume per pulse. Over pressurized would make a rich condition. Stock pressure should be around 54psi.

A clogged injector will run lean as a stuck open injector will drop raw fuel on the piston causing a rich condition.
Don't rule out the ignition side either. Try pulling the plugs and look for a fouled plug. (black and wet) or look for a bright white which would be lean..

[bee_are_zee]

The main reason I'm leaning toward it being a fueling issue is when the motor is running on DI everything looks fine.

[clayrush]

Originally Posted by bee_are_zee

I'm between bad injector or in tank pump. Were you able to log a low fuel pressure before you pulled the pump?

Yes. My shop said it was making 16 psi instead of 60. Also said it was lean.

[sirsol66]

I've actually had the same thing with the same setup (OFT300 package); at initial startup the fuel trims are all over the place and then settle down to basically +/- 5~10%, including idle and cruising.

I asked Shiv about this and he said that it was normal.

Can anyone confirm?
Also can anyone tag Shiv? Not sure how it works on here.

[Kodename47]

Originally Posted by sirsol66

I've actually had the same thing with the same setup (OFT300 package); at initial startup the fuel trims are all over the place and then settle down to basically +/- 5~10%, including idle and cruising.

I asked Shiv about this and he said that it was normal.

Can anyone confirm?

It's normal

[bee_are_zee]

Originally Posted by sirsol66

I've actually had the same thing with the same setup (OFT300 package); at initial startup the fuel trims are all over the place and then settle down to basically +/- 5~10%, including idle and cruising.

I asked Shiv about this and he said that it was normal.

Can anyone confirm?
Also can anyone tag Shiv? Not sure how it works on here.

That sounds pretty normal. However I am much farther out than 5-10%

[CSG Mike]

I consider +- 5-10% unacceptable; I would be up in arms if a tune had me sitting at more than, at a maximum, +-5%. Even fuel variance from the pump, at an extreme, won't cause more than 5%.

Popping an o-ring off on your fuel pump means faulty installation; if you use both o-rings supplied with the DW pumps, you can't have a leak that causes that failure. Typically 3 are used for installations to prevent that with this car.

OP are you getting a bank 1 or bank 2 over rich, and/or a fuel trim bank mismatch code? I need more info to help diagnose.

[clayrush]

Originally Posted by CSG Mike

I consider +- 5-10% unacceptable; I would be up in arms if a tune had me sitting at more than, at a maximum, +-5%. Even fuel variance from the pump, at an extreme, won't cause more than 5%.

Popping an o-ring off on your fuel pump means faulty installation; if you use both o-rings supplied with the DW pumps, you can't have a leak that causes that failure. Typically 3 are used for installations to prevent that with this car.

OP are you getting a bank 1 or bank 2 over rich, and/or a fuel trim bank mismatch code? I need more info to help diagnose.

May very well have been a bad instal because my shop fixed it for free. Popped may have been the wrog term. The tech said one of the o rings broke.

The guy working on it told me
"Pulled the pump, and an o-ring broke. Caused a fuel leak in tank at the pump. Made a Delrin spacer to keep the o-ring where it needs to be since your old one from your old pump didn't fit."

Maybe they lost or did not use all the o rings supplied