Hesitation/Misfire under boost

[mcrane]

Car: 2013 Scion FR-S

Mods:
K&N High Flow Filter
Custom Intercooler Piping
Water/Air Intercooler with Bosch Water Pump
Garrett GT28 Turbo (Internally Wastegated)
Turbosmart BOV
Innovate SCG-1 Electronic Solenoid Boost Controller/Wideband
Mishimoto Oil Catch Can
OMNI Power 3 Bar MAP Sensor
Bosch 550CC Injectors
NGK Iridium Sprk Plugs (.28 gap)
CP Pistons (Stock Compression)
BC IBeam Rods
King Bearings
AEM High Pressure Fuel Pump
ACT Stage 4 Clutch
ACT Lightweight Flywheel
TRD Catback Exhaust
Custom Up pipe and Downpipe

Issue:
Vehicle was dyno tuned with DW 700CC Injectors. Tuner had a difficult time getting the car to idle. After 6 hours, he was able to get it to idle. A couple hours later the vehicle was making power. Tuned to 250hp. After leaving the tuner, a noticble hesitation and stumble occurred at 4000 rpm consistently. The vehicle would misfire and shake and die when stopping. This only seemed to occur under boost at 4000 rpm. Sometime the vehicle would pull clean, but generally it would hesitate each time. At high speeds (highway) the vehicle seems to be fine. The vehicle does not do this with the Stock Injectors and MAP Sensor. Also, the car does eventually build full boost once it moves past the stutter.

Replaced:
Coil Packs
Spark Plugs
MAP Sensor
Cleaned the MAF
Swapped to 550cc injectors

Vehicle was brought back to tuner with 550CC injectors. Once on the dyno, the tuner noted the hesitation. He noticed that the when putting he AFR sniffer in the drivers side tailpipe, the AFR was rich. But in the Passenger Side Tailpipe, the AFR was Lean. He eventually got a good read and tuned the vehicle to 270hp before it started having symptoms of a slipping Clutch. Once on the street, there was no hesitation and no clutch slip whatsoever. The vehicle did however pull timing on the street. He added 10% fuel to beef it up and remove knock. The car pulled clean all the way home (100 mile drive). Towards the end of the drive, the car developed the hesitation once again. This time between 4,000 and 5,000 RPM

At this point, the MAP Sensor, Coil Packs, Spark Plugs, and injectors have been changed out. The original 700CC injectors were tested and returned from DW with a clean bill of health. So it isn't the injectors.

CODES encountered throughout the process:
Random Misfire detected
U0155 - Instrument Cluster Communication
Idle Air Control High Output

This is driving me crazy. Does anyone have any ideas what could be causing this? Thanks.

[Cal3000]

Similar thing was happening to me, but it was the coil pack.
If you changed out your coil pack and plugs, then I would look at the direct injector seals next. That could cause hesitation. Which cylinder are you misfiring in? Get a compression test. There are also special cases when the direct injector gets too hot, they can malfunction.

[mcrane]

The misfire is occurring in all cylinders. When plugging in the Snap-On, all Cylinders are misfiring.

[Fred E]

Can you share any datalogs of the misfiring/hesitation?

[Kodename47]

Is the tuner used to the platform? Sounds like it could be trying to run the DI too close to the spark event.

[SoCal80six]

Had the same problem it was coil packs took forever to find out what was causing it..

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[kimcheefists]

Have you done a boost leak test? Also, make sure your MAF sensor is clean

Edit: just saw that you already cleaned the MAF

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[mcrane]

Replaced all four coil packs

[mcrane]

Originally Posted by Kodename47

Is the tuner used to the platform? Sounds like it could be trying to run the DI too close to the spark event.

DI and PI are always running. Plus, it doesn't do this with the stock tune and injectors/MAP

[idkwhatimdoing]

Originally Posted by mcrane

Car: 2013 Scion FR-S



Mods:

K&N High Flow Filter

Custom Intercooler Piping

Water/Air Intercooler with Bosch Water Pump

Garrett GT28 Turbo (Internally Wastegated)

Turbosmart BOV

GFB Manual Boost Controller

Mishimoto Oil Catch Can

OMNI Power 3 Bar MAP Sensor

Bosch 550CC Injectors

NGK Iridium Sprk Plugs (.28 gap)

CP Pistons (Stock Compression)

BC IBeam Rods

King Bearings

AEM High Pressure Fuel Pump

ACT Stage 4 Clutch

ACT Lightweight Flywheel

TRD Catback Exhaust

Custom Up pipe and Downpipe

Glowshift Boost Gauge



Issue:

Vehicle was dyno tuned with DW 700CC Injectors. Tuner had a difficult time getting the car to idle. After 6 hours, he was able to get it to idle. A couple hours later the vehicle was making power. Tuned to 250hp. After leaving the tuner, a noticble hesitation and stumble occurred at 4000 rpm consistently. The vehicle would misfire and shake and die when stopping. This only seemed to occur under boost at 4000 rpm. Sometime the vehicle would pull clean, but generally it would hesitate each time. At high speeds (highway) the vehicle seems to be fine. The vehicle does not do this with the Stock Injectors and MAP Sensor. Also, the car does eventually build full boost once it moves past the stutter.



Replaced:

Coil Packs

Spark Plugs

MAP Sensor

Cleaned the MAF

Swapped to 550cc injectors



Vehicle was brought back to tuner with 550CC injectors. Once on the dyno, the tuner noted the hesitation. He noticed that the when putting he AFR sniffer in the drivers side tailpipe, the AFR was rich. But in the Passenger Side Tailpipe, the AFR was Lean. He eventually got a good read and tuned the vehicle to 270hp before it started having symptoms of a slipping Clutch. Once on the street, there was no hesitation and no clutch slip whatsoever. The vehicle did however pull timing on the street. He added 10% fuel to beef it up and remove knock. The car pulled clean all the way home (100 mile drive). Towards the end of the drive, the car developed the hesitation once again. This time between 4,000 and 5,000 RPM



At this point, the MAP Sensor, Coil Packs, Spark Plugs, and injectors have been changed out. The original 700CC injectors were tested and returned from DW with a clean bill of health. So it isn't the injectors.



CODES encountered throughout the process:

Random Misfire detected

U0155 - Instrument Cluster Communication

Idle Air Control High Output



This is driving me crazy. Does anyone have any ideas what could be causing this? Thanks.

Running rich I think. Got the same thing when I ran my blower tune on NA lol, felt like clutch slippage. Car would die randomly


________

~refer to username~

[mcrane]

Originally Posted by Kodename47

Is the tuner used to the platform? Sounds like it could be trying to run the DI too close to the spark event.

Originally Posted by idkwhatimdoing

Running rich I think. Got the same thing when I ran my blower tune on NA lol, felt like clutch slippage. But when driving on the street he detected no slipping


________

~refer to username~

The tuner said it felt like my Clutch was slipping on the dyno and it does die randomly.

[idkwhatimdoing]

Originally Posted by mcrane

The tuner said it felt like my Clutch was slipping on the dyno and it does die randomly.

Engine dying randomly isn’t a symptom of clutch slip. If your rpms stutter at a certain rpm, it’s not the clutch. 4k rpm i believe is a transition state for the injectors between DI and PI, i forget which kicks in at that point. During clutch slippage, the rpms will spike. Is that happening?


________

~refer to username~

[mcrane]

Originally Posted by idkwhatimdoing

Engine dying randomly isn’t a symptom of clutch slip. If your rpms stutter at a certain rpm, it’s not the clutch. 4k rpm i believe is a transition state for the injectors between DI and PI, i forget which kicks in at that point. During clutch slippage, the rpms will spike. Is that happening?


________

~refer to username~

I misspoke. It only died after resetting the fuel trims. Once it relearned it was fine.

[sid94]

Put oem plugs in it. They’re good for pretty high hp. I had a random cylinder misfire code when I was breaking in my engine cause I had put a set of ngk “for break in” and it would throw me that code and hesitated like a old man before farting. Swapped oem plugs and car ran great after that


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