Low power issue thats bugging me for a year... Seeking help

[Connor H]

whats up guys,

I have been trying to find this low power issue for about a year where ive exhausted myself of ideas.

It makes boost, perfect vacuum no leaks etc. but the car feels like its heat soaked 24/7. laggy and no torque at all. im thinking its something not playing nice with the tune anymore , maybe the ecu asking for less.

I have VCDS and there's no codes. Ive tried to log a few basic things but nothing stood out and im not sure what to look at next. So any guidance would be massively appreciated

No codes so completely stabbing in the dark

• Changed spark plugs no change
• Maf is reading low, but tried a working one with no difference
• Changed VVt unit last year to a decent but non OEM, no codes or issues after but tried a working OEM VVT solenoid and no difference
• Checked the TIP and turbo for mechanical issues, none except a small crack on the wastegate
• aligned the throttle body
• pressure tested
• cleaned sensors and TB
• car never overheats but it easily gets heatsoaked and stuck at 5psi from mild traffic

Im open to logging whatever needs. Ive attached a 4th gear pull (before i ran out of road) to get the ball rolling

Cheers

 

[mty12345]

All looks ok from those logs, i take it it's a stage 1 AUQ?
Could log the O2/lambda values for the fueling, think it's group 031 or 032
3rd gear is OK for logs too, 4th is a bit impractical seeing as your well into triple digits on whatever private road you use
What fuel are you using?
Would be good to log the knock/ignition delay too, can't remember what group that is off the top of my head, but the values are titled KW and the measurement units are in the format of 0.0degrees etc. Cylinders 1,2,3 are in one group and cylinder 4 in another

 

[Connor H]

hey mate

Its stage 2 so meant to be at 240hp, but definitely is down on power cos my mates stage 1 bora smokes me.

I checked the fuel trims on 032 last night, that was at -0.2% / 9.4%

using 99octane, tesco momentum or v power

i'll find out what blocks are knock/ignition delay and get back to you with some logs

cheers

 

[Connor H]

To return to this after a lot of crap got in the way.

I managed to log fuel and timing with no visible issues. its not leaning out and its not pulling timing

I still cant figure out what could cause a low maf reading without it being the maf itself. Im wondering if its the ECU asking for less of its mechanically choking somewhere.

 

[Alexis27]

Are you on your original fuel pump?

 

[Connor H]

Are you on your original fuel pump?

Im running a sytec pump.

 

[Connor H]

Does anyone think it could be my turbo? I make 24psi when cool but the power delivery is so flat, doesnt throw you back in the seat, and is slow to build back up after shifting.

The other thing to mention even on a 23c day of town driving the car gets stuck at 5psi and stays that way until a long drive cools it down. Im thinking its heat related but everything in the ecu is reading correctly, so maybe the turbo/wastegate/actuator getting hot for some reason?

might explain the low air flow the maf is seeing...

 

[Alexis27]

Sorry if you've already tried this, but a sticking N75 valve will cap the turbo at 5psi.

 

[Connor H]

Sorry if you've already tried this, but a sticking N75 valve will cap the turbo at 5psi.

I will try borrow my mates n75 and see if it changes anything. Mines only a few years old from the stealers so i hope its not that lol. I think at this point ive swapped/replaced most sensor parts except the throttle body and n75.