Problems with surging and driveability - datalog attached

Make sure you are viewing them on the same scale. using datazap.me it looks like your banks 1 and 2 are doing nearly the same thing. I see no problem there.

If I had to guess I would say your throttle body is the cause of your surging. your MAF is following your throttle and the throttle is opening and closing not very smoothly. Pedal position, which is usually smooth is following throttle angle like its in open loop. Usually it's only in open loop at WOT. A tune can change this or a physical problem could cause the throttle body to use open loop through the closed loop intervention prevention safety feature. I assume a dealer would flash a stock tune on the car to undo any previous modification. That kinda leaves a physical problem with the throttle body or wiring. That's my best guess.

 

Take it to another dealer if still under warranty. If not have it dyno tuned, that will have the car driving it's best.

 

Best thing is a dyno tune then, they check for things to make the car run its best. A dealer is opposite where they don't want to find problems especially while the car is under warranty. An email tune will only show so much and you'll have to trouble shoot the rest yourself. Dyno tune in person will get the car running how you want for about 500.

 

Also does the car have any power mods? Only issue I've had like that was from a jlt intake. Maf didn't really seal that well and didn't like how it drove.

 

Maybe you just got a lemon but a dyno tune is your only chance. Those guys want to work on your car and earn business. If they can't get it running maybe trade it in at these dealers who say it runs "good". I've gone through driveability issues as well before. Dealer and data logs through email tunes are a shot in the dark. Again, dyno has best chance of seeing the car run optimally. If your totally against maybe time to cut your losses.

 

If the car is stock suggesting he get a dyno tune is a stupid idea. Why would he do that? Also dyno tuning is not the way to go anymore but rather an email tune and logging the car on the street in real world conditions.

Others have had the same symptoms as you and it turned out to be a cracked manifold. Something I would look into.

 

Actually i had a surging issue with a jlt intake unable to diagnose. Then later a minor exhaust leak causing car to pull timing. Both issues were through the "best" tuners I'll leave names out. They could see it on the logs but had no ideas other than bad gas. On a dyno where they can check connections in person both problems were solved in 10 minutes. So no its not anymore stupid than continued trips to the dealer where they say everything is fine. Data log will show issues but what good does it do from a guy 1000 miles away who can't look at the car? He doesn't necessarily need the car tuned. Just hooked up to the rollers and have his logs checked in person.

 

As you can see your angle actual and voltage are inverse from each other and move with each other. You want to compare throttle to accel pedal. I think its doing what it should be doing.



Looking at your fuel, I don't see anything wrong. LTFT are +/- 1%. STFT are +/- 4-6%. This is totally normal. Your measured lambda is exactly where it should be with no deviations.



Your cam movement is normal as well. When the load goes up (from A/C, alternator load, ETC.) the exhaust cams retard to boost engine torque to handle extra load.



Looking at the air flow from your MAF it looks fine as well. thottle body moves with load to increase airflow. It does it with out the driver knowing or needing to move their pedal. You do get torque source 13 intermittently when load increases. This could be what you are feeling.



Torque source 13 is OSCMOD / Anti-Shuffle. This mode is to reduce the chance of bucking and surging from starting that can occur from the engine or drivetrain changes during steady state accelerator pedal conditions.
When TQ source happens you can see spark is reduced and fuel is kept stoich. When it doesnt happen your fuel goes rich for a couple seconds.


I would say try to note where you are feeling the surging/hesitation and if it correlates with the TQ source 13 or when it misses the TQ source 13 and load increases. This can be disabled in a aftermarket tune if it does correlate. If it correlates with a missed torque source 13 your dealer may need to update the ECU's tune.

Can you get a log with output shaft RPM? you can compare it to engine RPM and vehicle speed to isolate where the surging/hesitation may be coming from.

 

What kind of fuel are you running?

 

How many miles on the car? I would try some CRC GDI cleaner if over 10k. Direct injection is great but intake valves stay dry and don't get fuel washed with detergents can build up some carbon. When I had my 13 mustang I was using methanol so never had to worry about this. In my DD now 2.0t 15 sonata at 15k my car had a very noticeable cold start, part throttle hesitation, and drop off in mpg's. One can of the GDI cleaner followed instruction all was good. Now at 30k coming back will have wash and repeat.

 

These cars use port injection.

The 2018s have direct and port.