fuel not shutting off?

[vdubnick]

weird issue i have been having for a while now, 2013 GTI (see sig), when driving, in gear, i let off the throttle and the car slows.... but a few seconds later it decelerates harder.

I have tracked this down to a fuel cut issue. which coincides with the "consumption" readout. Sometimes, it takes less than a second for the fuel to cut, and letting off the throttle is almost an immediate deceleration. But more often it seems like it takes up to 5 seconds for the consumption to go to "-.-- mpg" and FEEL the deceleration.

This is annoying because I am having to brake sooner than I did before. This started happening a while ago, long after any engine modifications. I have also noticed a 15-20% drop in fuel economy. As far as i can tell the accelerator pedal is operating correctly, and i have reset the TB multiple times with no change in performance. Although, i feel a little jerky engagement when partial throttle at lower RPMs, may be related.

What else would cause the fuel injectors to keep running after letting off throttle completely (in gear, RPM 1500+)? I have verified the intake runner flap is still fully functional, although in OBDeleven, it sticks sometimes on light pedal, but no correlation to the throttle hang.

 

[jay745]

Have you done a smoke test? A vacuum leak can have the same symptoms you're describing

 

[vdubnick]

Have you done a smoke test? A vacuum leak can have the same symptoms you're describing

i have not yet... i guess i should but assumed that may not be vac leak since boost gauge shows normal vac and idle is normal.

 

[uglybastard]

Smoke test good place to start yeah, cheaper than throwing fueling parts at it (hpfp, lpfp, or fuel filter, eg.)

 

[vdubnick]

Smoke test good place to start yeah, cheaper than throwing fueling parts at it (hpfp, lpfp, or fuel filter, eg.)

well, smoke test turned up nothing.

i have found something tho, if im crusing around at low RPM (no matter what speed or gear), that is when the consumption hangs up to 5 seconds before going to zero, feels like the throttle is still partially engaged even tho i have verified via OBD that it is fully released.

At any engine speed above approx 3250 RPM, it cuts off within a half second every time. I am not sure what that has to do with it, but it is interesting that the fuel cut acts normal above 3250RPM, but hangs on anything below that.