Hello, first time poster.
My b7 A4 6mt, 204k kms, apr stage1 91/93 octane, afe cai, p3 gauge. It has been lacking significant power the day I bought it, almost as if there’s no boost, things I have replaced are, hpfp, lpfp, maf, map, pcv, tb, thermostat, temp sensor, cam follower for hpfp, n75, spark plugs, car has 0 faults. I’ve checked for boost leaks about 6 times in the last 2 months, and have found none, wastegate has 0 play, car burns just under a litre of oil in 7k kms, based on obd11 and the p3 gauge, the throttle is closing at wot, goes from 99.4 to 47 as soon as I get into boost, based on some logs, it’s pulling anywhere from 4-12 degrees of timing, I don’t hear any knock when I’m wot though, I believe the ecu is pulling everything back as a safety and I just can’t seem to figure out why, actual boost meets requested boost, lambda reads .8ish at wot, fuel trims are fine at idle, but partial (block 32-2) shows +23 when driving, lpfp is 4.7bar at idle and wot, duty cycle is 53% at idle and almost 80% at wot around 6k rpm, here’s what baffles me and I’m not sure if it’s due to the throttle angle closing at wot but I can’t get any maf reading higher then 103g/s at 6500 rpm, it’s about 2.8g/s at idle, fuel rail is 50bar at idle and have seen it as high as 120bar at redline. Obd11 shows up to 1800mbar of boost at about 5500 rpm, but my p3 gauge has never seen over 7psi, fluctuates between 3.5-7psi. I have switched back to stock map with 94 octane and same thing even slower with lower boost request. Apr was of no help when I reached out to them and didn’t reply when I sent them some logs. I have a couple saved logs that I would like to post of someone could tell me how, any help/advice would be greatly appreciated.

 

Know you said actual boost meets requested boost but have you checked intake valves/manifold for carbon buildup? Same could also apply on on exhaust and cat.

 

Literally just finished doing a carbon clean like an hour ago, wasn’t bad and wasn’t great, car runs better but definitely still not giving the power it’s supposed to, unscrewed the upstream o2 sensor and ran a camera under there everything seems to be intact and open on the cat, left the o2 unscrewed and went for a drive and no difference. But here’s where I’m really confused, I unplugged the maf, car ran somewhat rough but nothing serious, went for a drive, it was even slower, but the p3 gauge started showing peak boost of 18psi, and throttle held at 100 at wot, but still no power, could the maf be bad regardless if it’s new ?

 

Ref OBD boost - probably need to adjust the value shown for base atmosphere. Peak boost of 18 PSI per P3 guage is in the right area.. I have Revo Stage 1 and my boost holds around 18psi with spikes up to 23psi; my MAF reading are 1.6 g/sec at idle and in the 155-165 g/sec at full boost.

 

How can base atmospheric be adjusted ? Also even with things reading better with maf unplugged the car is still very slow.

 

You don't - the sensors on the car measure air pressure after the turbo and base atmospheric before - the difference is what we call Boost (ie increase above atmosphere). The ECU uses it's air/fuel map and MAF readings to determine what boost to request and things interact with the turbo and fuel flow to get to the value requested. IMO things shouldn't work better with any factory sensor removed but only APR can tell you what sensors there remapped tune is dependent on. My suggestion would be to try a different MAF; if you don't want tp try another new one, maybe it's worth trying to get a used one from a junkyard - at least for test purposes anyway.