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Author Topic: Loss of power past 5.5k rpm in 4th gear or above  (Read 1120 times)

Offline ZoliWorks

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Loss of power past 5.5k rpm in 4th gear or above
« on: September 08, 2024, 11:02:37 am »
I think I'm having misfires above 5.5k in 4th gear or above. No fault codes or anything but the power cuts out for a second or so and the DV opens to let out boost.

Stock lpfp, vis hpfp internals, 145 bar fprv, stock injectors, stock boost sensor, stock rail pressure sensor, k04.

NGK u5014 red coils with bkr7eix plugs with their default gap of 0.8. Ordered a set of pfr7b's cause they are gapped at 0.7 to see if it makes any difference. I've seen a few forum posts saying you need a 0.7 gap for red coils. I no longer have my old black coils to test so new plugs was the next best step.

Also no fault codes whatsoever. Fuel rail pressure is maintained at 130 bar but every now and then requested jumps to 140 then back to 130 in the span of a second. This happens when I change gears. Boost pressure is at 2560mbar till 6.5k with an 82-85% wastegate duty cycle. Camshaft timing is 28 degrees requested, 29.5-30.5 degrees actual. I have replaced the chain, regulator and the variable wheel itself, but didn't change the seals that go into the VVT wheel which are mounted on the vvt housing. LPFP pressure is usually above 5 bars but every now and then drops a bit, no lower than 4.5 tho. I did the fuel line drill mod to let if flow better as per the suggestion of the guy over at Vis.

Usually no misfires but if I drive it hard then come to a stop, it does log a few consecutively, then out of nowhere, resets itself, clears all logged misfire counts and doesnt misfire anymore.

Above 5.5k


Below 5.5k




After fitting the new plugs, I'll go for another run. What should I log? Ignition timing per cylinder, injection timing per cylinder, misfire counter per cylinder?
« Last Edit: September 08, 2024, 11:42:29 am by ZoliWorks »
Mk5 Jetta 2.0 TFSI BWA | Manual | Mk6 GTI Front | BorgWarner K04 Turbo | Sachs X-Tend OEM+ Clutch Kit | Ta-Technix Air Intake | Ta-Technix 200 Cell Downpipe | Ta-Technix Intercooler | Stock Injectors | Vis Motorsport 175 bar HPFP | 300hp


Offline ZoliWorks

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Re: Loss of power past 5.5k rpm in 4th gear or above
« Reply #1 on: September 08, 2024, 03:26:08 pm »
Aight so I've done another log where I logged lambda and injection timing then spoke with a local tuner. He says my injection timing is too much and my lambda is maxed out at 25% because 1.55 bar boost is too much for my setup. He recommends a remap for 1 bar boost. He showed logs where he made 375hp on 1.35 bar boost. He also said that 340hp and 450nm is the safe limit on my stock BWA internals and that he can make that happen with 1.2 bar boost.

I'm thinking about taking his advice and getting the car remapped at him. It would cost 380 euros for the remap and dyno and later on 190 euros to adjust the map when I fit s3 injectors. He said I dont need the 200 bar rail sensor or 3 bar boost sensor as he can work with the stock ones.


« Last Edit: September 08, 2024, 04:53:25 pm by ZoliWorks »
Mk5 Jetta 2.0 TFSI BWA | Manual | Mk6 GTI Front | BorgWarner K04 Turbo | Sachs X-Tend OEM+ Clutch Kit | Ta-Technix Air Intake | Ta-Technix 200 Cell Downpipe | Ta-Technix Intercooler | Stock Injectors | Vis Motorsport 175 bar HPFP | 300hp