Dealer replaced injectors and water pump and now power delivery and shifts are awful.

[ManiacGT]

So late 2017 my car developed a cold start misfire. I booked the car into the local dealership.

On the way to the dealership the car overheated (amber warning) and as I rolled into the dealer car park I got a red warning to stop the car, which I did.

They diagnosed water pump failure and the misfire as faulty injectors.

Both were replaced and the car returned to me.

The following day under cold start I noticed the car felt lazy and I put it down to perhaps a reset of some adaptations by the dealer.

Several weeks later it got no better and then followed several months of back and forth to the dealer for them to ultimately give up as they could find no fault codes nor detect or understand what I was telling them.

Essentially the cars power could feel sloppy and lazy one day then fairly normal the next.

However DCT shifts were snatchy (used to be smooth) and power drops away after shifts before recovering seconds later. It’s unpredictable and unnerving to drive.

I took the plunge to apply MHD stage 1 and this allowed me to play with wastgate settings etc and putting the setting into low lag improved this snatchy and power drop off but it didn’t make the car as it used to be.

A number of forums are telling me different things about the MHD logs I’m pulling but no one has any idea of the cause.

I took a plunge to replace turbo solenoids but that made no difference.

Vac pipes seem to hold vacuum.

I’ve tested diverter valves and they seem ok.

A bit lost now...

 

[aus335iguy]

Great, You’ve ruled that out. @BQTuning What would you suggest for this fella given his logs? Considering that hes stock and both the stock and OTS maps exhibit the same behaviour...
@ManiacGT please correct me if Ive misunderstood?

 

[BQTuning]

I am going to take a swing at it and send him a my own calibrations for the DCT to see how that works. Im in middle of clearing my table with current customers first then I will send him a test map.

 

[aus335iguy]

I am going to take a swing at it and send him a my own calibrations for the DCT to see how that works. Im in middle of clearing my table with current customers first then I will send him a test map.

You’re a gentleman Dimitri

 

[ManiacGT]

I am going to take a swing at it and send him a my own calibrations for the DCT to see how that works. Im in middle of clearing my table with current customers first then I will send him a test map.

That is very generous and appreciated. I still wonder on an otherwise stock car what the root cause is. There has to be a hardware issue somewhere...

 

[ManiacGT]

So an update... BQ kindly sent a map and it generated a fuel pump plausibility and boost sensor overrun code. Just waiting to hear back on his thoughts. I wonder if this is HPFP (had it replaced in 2010).

 

[Optigrab]

So an update... BQ kindly sent a map and it generated a fuel pump plausibility and boost sensor overrun code. Just waiting to hear back on his thoughts. I wonder if this is HPFP (had it replaced in 2010).

Not sure if you are still having jerkiness issues but i had the same thing after i coded my injectors.
They should have cleared all adaptations after coding which included throttle if you don't complete the throttle adaptation procedure fully it will cause all sorts of jerky behavior. Once i reset the throttle and drove 200ish miles everything was back to normal

 

[ManiacGT]

Yes I’ve tried the adaptations thanks. I’ve no idea what the root cause is now and no one seems able to find it.

So it’s either time to move on or I keep spending randomly replacing things until I find the cause but that could be very expensive for a car less than £10k in value now.

So frustrated.

 

[Optigrab]

are you a dct?

https://www.1addicts.com/forums/showthread.php?t=1251909


https://www.1addicts.com/forums/showthread.php?t=1402323

 

[ManiacGT]

So I detected some symptoms I’d not seen before today as I took the car on a 120 mile trip... around 10 miles into the trip I thought the car was going to break down... it started to accelerate forwards for a second then drop back to normal for a few seconds then it would cycle round like this.

Very unnerving, it wasn’t violent but was enough to make my head sway back and forth. After around 10 minutes it stopped doing this.

It then repeated later in the journey and at first as it was a windy day I thought it was the wind pushing the car around but it was too regular.

It then did the same thing a few miles into the journey on the way back. Static pedal, 60mph and it surged forward a bit then dropped to normal then surged forward again then back to normal and cycled like this for several minutes.

This car is an enigma.

 

[aus335iguy]

So I detected some symptoms I’d not seen before today as I took the car on a 120 mile trip... around 10 miles into the trip I thought the car was going to break down... it started to accelerate forwards for a second then drop back to normal for a few seconds then it would cycle round like this.

Very unnerving, it wasn’t violent but was enough to make my head sway back and forth. After around 10 minutes it stopped doing this.

It then repeated later in the journey and at first as it was a windy day I thought it was the wind pushing the car around but it was too regular.

It then did the same thing a few miles into the journey on the way back. Static pedal, 60mph and it surged forward a bit then dropped to normal then surged forward again then back to normal and cycled like this for several minutes.

This car is an enigma.

Are you logging in MHD and can we look at the logs ?

 

[Optigrab]

So I detected some symptoms I’d not seen before today as I took the car on a 120 mile trip... around 10 miles into the trip I thought the car was going to break down... it started to accelerate forwards for a second then drop back to normal for a few seconds then it would cycle round like this.

Very unnerving, it wasn’t violent but was enough to make my head sway back and forth. After around 10 minutes it stopped doing this.

It then repeated later in the journey and at first as it was a windy day I thought it was the wind pushing the car around but it was too regular.

It then did the same thing a few miles into the journey on the way back. Static pedal, 60mph and it surged forward a bit then dropped to normal then surged forward again then back to normal and cycled like this for several minutes.

This car is an enigma.

Have you checked your engine ground and ECU connections?

This reminds me of those JB4 threads where people take it out and dont fully reconnect everything they have loose connections causing weird issues

 

[ManiacGT]

Are you logging in MHD and can we look at the logs ?

There are loads of logs I’ve put on here and other forums, they show severe timing pulls before shifts (more than normal for DCT) which is effectively what I feel.

I’ll try and take some more soon and post them up again.

 

[GreyNBlueE92]

I accidentally coded my injectors wrong the first time i did coding and it ran like crap. I'd like to think they messed up the coding somehow. Wrong decimal place, etc. Things happen.

 

[Optigrab]

I accidentally coded my injectors wrong the first time i did coding and it ran like crap. I'd like to think they messed up the coding somehow. Wrong decimal place, etc. Things happen.

Why not recode your injectors and battery yourself? reset adaptations drive cycle etc

 

[ManiacGT]

Why not recode your injectors and battery yourself? reset adaptations drive cycle etc

I’ve certainly done that with my car and it’s made 0 difference to the weird power delivery and crappy dct upshifts. I’ve checked piping, diverter valves, etc but still all I see in MHD is severe timing pulls.

It’s worse when cold, better after a short drive/shut off/ start back up (so on way to shops crappy, on way home, much improved (but not right). Dealership say no codes means unless they detect it by the seat of the pants then nothing is going to be done. They think because they’ve nothing to compare it to that the power pulls around shifts are normal. Ffs...

 

[ManiacGT]

A log I took today. Cold start, driving local streets at normal speeds (not WOT)

You can see the severe timing pulls around each shift, corresponding throttle closures, even the lift off the accelerator pedal due to such severe loss of power (feels like I’m dabbing the brakes)...

Log is of interest after the 4 second mark.. revs go up, before the shift timing drops as does torque, (it’s supposed to a little on DCT but not like this).

https://datazap.me/u/maniacgt/normal-driving-oct?log=0&data=2-3-14-20-23-24

 

[ManiacGT]

As Euro parts had a good discount on I’ve bought six new plugs and coil packs, worth a shot. After that it’s Vanos solenoids And then I’m going back to the dealer for a full every single module reflash. This is it then, if the fault remains then it has to Be something major And I’ll just give up.

 

[aus335iguy]

You may have tried it already but Can you confirm if it happens with traction control completely off ?ie long press DTC button between the air vents.

 

[ManiacGT]

You may have tried it already but Can you confirm if it happens with traction control completely off ?ie long press DTC button between the air vents.

Yes no matter the traction setting, same issue.

Comfort mode = long lazy power drops just before and after shifts, sport mode = much shorter and snatchier power drops when shifting.

I did wonder how I might disable the abs sensors (create a malfunction) which would turn off all traction systems to test that an option.

 

[ManiacGT]

Just installed the new plugs and coil packs. No difference other than idle is smoother. Plugs looked fine. Original Cyl 1 coil pack was missing a piece of insulation so that might explain the occasional cyl one timing correction.

I’ll try Vanos solenoids now then software at dealership then I’m calling it a day. That would be a shame tho, might be 9 yrs old but with only 37k on the clock it’s hardly used.