Ok, just bought the car a week ago for close to nothing. it's a 2000 a4 avant. Automatic. 1.8t. ATW
Here's the problem, I can't bet the thing to boost!! And it hesitates and stumbles around 3-4k
I have both smoked the intake for vacuum leaks and built a boost leak tester. I found 1 cracked vacuum line and a loose hose clamp. Both of those are now fixed/replaced. The car runs at 18 +/-1 in/hg at idle. It feels like it boost just fine in 1st and second gear. Once the car gets into third, it becomes extreme slow. It won't accelerate up hills and it takes forever to get to 80 on he highway. It gets to around 3000 and it sound like the motors bogging like crazy. Sound like it's running rich and during out. It slowly climbs rpms and at 4000 it decides it's not going to go any higher, it will sit at 4000 with almost no power refusing to go any higher. However if I'm on the highway and I step on it to downshift into 4th or 3rd, it will go all the way to redline, slowly and without any noticeable power.
The specs:
-No boost or vacuum leaks, pressurized charge pipe to 15psi, no leaks, smoked intake, no remaining vacuum leaks.
-Brand new 710N diverter, old one wasn't sealing, could blow through it
-Unplugged N75 valve from waste gate and took it around the block gently, no noticeable power increase, HOWEVER, it did set an over boost code
-It keeps setting an intermittent code for bank 1 sensor 1 02 sensor high voltage, I've read that can cause an issue
-Tried driving the car with the MAF unplugged, changed nothing, felt a bit more sluggish
-I can HEAR the turbo spooling and I DONT hear any obvious or major boost leaks while driving.
- according to the Verus(snapon scanner) the actual boost and desired boost are almost identical but no power.
I'm assuming the car thinks it has more boost than it actually does? Possibly? Not sure.
-I didn't see it pulling timing out under load so I'm not suspecting a bad knock sensor.
-Car feels like it's running rich and it's burning gas like crazy, wasn't able to view fuel trim on scanner, scanner didn't list those pids for some reason.
-It's also setting a p0411 code, smog pump is shot, apply power to motor and nothing happens.
My biggest issue is trying to figure out why it won't go over 4000 but I'm pretty sure that's tied into the boosting issue. Car doesn't smell like it's running rich but it's dumping fuel according to the gas gauge and the numbers on the gas pump.
Let me know if there's any tests or anything I can do to try to come to an answer. This one is kicking my @ss.
If worst comes to worst, I might have to pull the cat off to check the waste gate action. But I really don't want to touch a 17 year old cat for the first time. I feel like it's something simple that I'm just overlooking. Please help!
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