[YIT470]

Hi, first post but a long time reader.

In January I bought a 2013 i40 auto diesel. Ran nicely to start, but quickly developed a flutter/stutter that has appeared off and on quite randomly. Engine light - P2015 appeared, but has since gone and no record of it in diagnostics.

As time has passed, the issue has intensified and become more common. Current symptoms:
At idle - sometimes will oscillate between 800-900 revs, rough.
Under light acceleration - engine has a flutter/stutter, can even seem to kangaroo hop, particularly occurs shortly before changing into the next gear.
Cruising - at any speed eg 40kmph, 60, 80, 90, 100 will stutter, whether using cruise control or just pedal.
Deceleration - when coming to a complete stop, it struggles to find the right idle speed and will feel like it wants to stop, even though it doesn’t drop below 800revs.
Increased fuel consumption by 1-2L/100kmph (15-20%)
At times, simply runs rough while cruising, a mild engine vibration.

However, these symptoms still appear random. For example, today they were apparent for the first 1/2hr of driving, around town and on the highway, several stops. Then later, it’s driving smooth as can be after having not driven the car for 1/2hr.

Attempted fixes already done:
Engine clean using spray into throttle body (after first go, it ran smooth for a week before returning to usual problems) Manual clean of throttle body, intake manifold,  egr pipe (ran smooth for an evening, then returned to problems). Test of injector leak off (all good). Test for electrical leakage, no issues. Fuel injector cleaner additive in fuel, fuel doctor additive for diesel bug. Clean of MAFS, Turbo Boost pressure sensor. Manual I ntercooler clean. Replacement of SCV.

Next: will change fuel filter early. Also replacing air intake hose due to a recent crack in it, but have temporarily taped it up to reduce vacuum leak. Current KMS - 199,000.

I have been reading and watching everything I can find, and my father who’s a retired mechanic has been assisting. Would greatly appreciate some direction as I’m losing my mind  Thanks in advance.

[J]

Hi,
Same symptoms here, did you find what was the cause ?
Thanks

[YIT470]

I’m not sure I’ve completely eradicated the issue, but I have been able to dramatically improve it.

I took it to Hyundai, they weren’t able to replicate the issue, but told me I had faulty Injectors which would be causing the problem. Quote: $5-6000. Did not proceed with the work.

In the end, I grabbed a mates scan tool, and relearnt most of the engine related modules. The one that seemed to have the biggest impact was either relearning the EGR module or main computer module, I’d need to have the scan tool in front of me to confirm.

Has run well since… although I’ve noticed what could be early symptoms starting to appear again. My car has been in at the repairer for the last 3 months though (not at fault accident), so I don’t have a current assessment. But the kangaroo hop is gone completely, fuel efficiency is quite good again, stutter is gone.

I can’t explain why it’s seemed to work, but I know Hyundai was wrong about the injectors.