2016 PFL RS3 Hesitation at 5k RPM

[XPOWER]

My 2016 Pre-Facelift RS3 with the CZGB engine with 43K miles has started developing an issue when accelerating under full throttle.

At 5k rpm there is a noticeable hesitation and sometimes the revs dropping to 4k with the exhaust popping as if the accelerator had been lifted off.

When trying to recreate the scenario it can happen when accelerating and shifted to 3rd gear from standstill or accelerating with kickdown from a roll at 50mph.

There is no engine warning on the dashboard or traction control to give an indication what the issue could be.

It isn’t a constant issue as it can be fine and then it starts playing up again.

Any ideas what could be causing this only at 5k rpm?

 

[XPOWER]

Update on the hesitation issue .
It went in for a MOT and service at 44k miles at the dealer at the end of February and I did mention the issue.
They reported back that there were no fault codes logged so I thought it was nothing too serious and left it.

Over the next few months the hesitation was there randomly but by the time it was coming up to 49k miles the hesitations was accompanied by an engine warning light coming on and going out within a few seconds.

I then booked the car into the garage which did the Revo stage 2 upgrades.
As a initial diagnosis I phoned up the dealer and they confirmed there was no record of them being changed.
It turned out the spark plugs were shot when the garage removed them.
They should have been changed as part of the service every 20k miles so missed out on 2 times they should have need changed.

The car is getting nice new uprated spark plugs and also had the transfer box serviced (which isn't par of any Audi service schedule) lucky I did ask for that to be done as the oil was in a state when they drained it.

So lesson learnt not to rely on the dealers to tell me what should or needs to be changed as part of the serviced.

 

[flybynite]

My car (DAZA) is low miles but now 6 years old and I had to prompt the stealer to change the plugs this service even though they are due. Going to change the coil packs to latest revision when they are done and I know the stealer has loosened them to get the plugs out

 

[XPOWER]

The sparkplugs did look very well used so I'm glad they were replaced.




When I went to collect the car there was still a random misfire when the garage was testing it so they had swapped the coil packs out to see how I could get on with it. When I went to start the car the random misfire was now a constant one and swapping the coil packs around had the same cylinder misfiring.



It turned out that it was the injectors were the issue. This was probably my fault for running Octane Booster for the last 3 years.

Driving the car home from the garage and it drives to much better even before the misfire started.

But on cold start up the car feels lumpy and the boost gauge has a reading at tick over. As soon as the car warms up it drives and restarts fine. So not sure what that issue is.


View: https://youtu.be/DcqOBS2gtGk

 

[flybynite]

This was probably my fault for running Octane Booster for the last 3 years.

Yeah I think most people recommend octane booster every other tank at most. some are not good for quite a few bits of the engine.

 

[XPOWER]

Another update. The lumpy cold start is still there but now there is a misfire being reported.

Here is the fault codes for the misfire.

10203 - Random/Multiple Cylinder Misfire Detected
P0300 00 [096] - -
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 75937 km
Date: 2023.10.20
Time: 15:35:27

Engine RPM: 1379.00 /min
Normed load value: 59.6 %
Vehicle speed: 1 km/h
Coolant temperature: 15 °C
Intake air temperature: 16 °C
Ambient air pressure: 960 mbar
Voltage terminal 30: 12.660 V
Unlearning counter according OBD: 40
Engine status: COENG_RUNNING
Engine status-Test_Program_Co Eng st COMPU VERB UBYTE: 3

10592 - Cylinder 2
P0302 00 [096] - Misfire Detected
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 75937 km
Date: 2023.10.20
Time: 15:35:27

Engine RPM: 1379.00 /min
Normed load value: 59.6 %
Vehicle speed: 1 km/h
Coolant temperature: 15 °C
Intake air temperature: 16 °C
Ambient air pressure: 960 mbar
Voltage terminal 30: 12.620 V
Unlearning counter according OBD: 40
Engine status: COENG_RUNNING
Engine status-Test_Program_Co Eng st COMPU VERB UBYTE: 3

10593 - Cylinder 3
P0303 00 [096] - Misfire Detected
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 75937 km
Date: 2023.10.20
Time: 15:35:27

Engine RPM: 1379.00 /min
Normed load value: 59.6 %
Vehicle speed: 1 km/h
Coolant temperature: 15 °C
Intake air temperature: 16 °C
Ambient air pressure: 960 mbar
Voltage terminal 30: 12.660 V
Unlearning counter according OBD: 40
Engine status: COENG_RUNNING
Engine status-Test_Program_Co Eng st COMPU VERB UBYTE: 3

So it needs further investigation by the garage to find out what is causing it.

 

[flybynite]

So it needs further investigation by the garage to find out what is causing it.

Have you put in new coil packs? As I understand it as you increase cylinder pressures tuning the car, it makes it harder for the spark to jump which can wear out the coil packs. Running on old plugs wouldn't help either.

After the stealer does the plugs next month I might treat mine to a new set of latest revision coil packs although it is bog standard, there is nothing wrong and only just cracked 30K. That has often made a difference to how a car runs in the past for me and I treat coil packs as consumable. Would be something I would change as matter of course.

 

[XPOWER]

Have you put in new coil packs?

When doing the initial diagnosis on the misfire the coil packs were changed and swapped around temporarily with old ones but the misfire continued.
It sounds like they will be the next obvious part to change.
Not looking forward getting that bill.

 

[flybynite]

Not looking forward getting that bill.

I think for yours they are about half the price of my DAZA. about £150 online? Easy swap yourself, at least you know they have loosened them

Is yours CEPA or CZGB?

 

[XPOWER]

Is yours CEPA or CZGB?

Mines a CZGB.
I must have looked at the wrong ones previously as I thought they were really expensive. Looking at Awesome GTI APR ones are only £35.75 each so £179 isn't too bad.

 

[XPOWER]

I’ve fitted the new APR Coil Packs and it has made the drivability of the car noticeable better.

With the 48k miles OEM coil packs there was noticeable bogging at higher rpm when accelerating the new coil packs has made the engine free revving.

Hard to say if there is a difference in the power or performance numbers but it was worth swapping the old ones out.

It hasn’t solved the lumpy idling on cold startup so will have to book it into the garage to have another look at what could be causing that .

 

[flybynite]

Glad the coil packs had some effect and weren't a complete waste of time. New OEM ones on my DAZA have made a small difference too.

One question is the CZGB dual injection? Off hand I can't see an MPI rail on your engine. Could the valves be a bit coked and need a walnut blast? 48K is a bit low for that but it does happen.

Octane booster can be hard on the oxygen sensors, is it still throwing the misfire codes?

 

[XPOWER]

One question is the CZGB dual injection? Off hand I can't see an MPI rail on your engine. Could the valves be a bit coked and need a walnut blast? 48K is a bit low for that but it does happen.

Octane booster can be hard on the oxygen sensors, is it still throwing the misfire codes?

I found a reference website to the engine but wasn't sure if it was Multi Port Injection or not from their description.

https://australiancar.reviews/Audi-RS3_CZGB_Engine.php

I did speak to the mechanic this week and he did say it could be a oxygen sensor. I will ask him about the checking if the engine is cocked up.

There hasn't been any misfire codes since the ones reported in October.

I can't understand how the boost gauge is flickering a few bars of boost when the engine is only at 1.5k with no throttle applied.

 

[flybynite]

Actually I remember now, iron block CEPA and CZGB have no mpi injection so I guess carbon build up might be something to keep in mind.

02 sensor probably easiest thing to check/replace first.

 

[8YARWY]

Easy to check just split the inlet chamber to check for carbon build up.
Yes correct the Daza etc were the 1st to get dual port injection.