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tdatk
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Failing turbo?
tdatk replied to mbagge01's topic in 9PA, 9PA1 (Cayenne, Cayenne S, Cayenne Turbo, Cayenne Turbo S)
UPDATE, I got a Durametric pro to see if anything was not showing up on my generic code reader.....yep....knock sensor bank 1. I am not getting any knock at all so I replaced it, same result. I got the wireing diagram and found out which wires go to each sensor to the DME. Knock voltages to the DME are whichcraft so I didn't bother to try and measure anything, I figured I'd try feeding both sensor inputs from the bank 2 knock sensor using a jumper. Worked perfectly, everything related to low boost was gone, boost and performance went through the roof compared to before and fuel mileage increased by 4 mpg highway to 18.5 mpg !!!! I will eventually replace the signal wire to the bank 1 sensor but at 185,000 miles, i'm not too worried. Thanks for your help. -
Failing turbo?
tdatk replied to mbagge01's topic in 9PA, 9PA1 (Cayenne, Cayenne S, Cayenne Turbo, Cayenne Turbo S)
Thanks, No overboost or cel's, only the issue with .04 boost. I am not ruleing out the dme interfering here as it also seem to hesitate and seems to be running rich. I don't have a durametric to see any values so I'm going by past knowledge. I have new coils, plugs and cleaned mafs and throttle plate. It's like a vacuum leak but it's not obvious. Also my vacuum tester indicates otherwise.....All the old plugs looked good but had 40k miles on them, so clean burn. What are the other change over valve tests you got? -
Failing turbo?
tdatk replied to mbagge01's topic in 9PA, 9PA1 (Cayenne, Cayenne S, Cayenne Turbo, Cayenne Turbo S)
I am suffering the same issues of building only .04 bar boost. After pulling and inspecting all the related vacuum /pressure lines, visually checking wastegate operation and both diverter valves, everything seemed ok. Still only .04b boost. I know the turbos are spinning ie;.04b on the gauge sooooooo, There are only 3 things that could be holding me back, diverter valves, change-over valve, N75 valve..... I pulled the change-over valve and plugged the vacuum and boost feed lines. I then borrowed the check valve from the pressure line and put in series my vacuum/pressure gauge on a "T". I then pressurized the diverter valve lines with 7b air knowing the check valve would hold the pressure....it worked perfectly (see attached picture). I did a test run and it built .08bar before popping off, but not for longer than a second.....hmmmmm, at least I knew it was capable!!!! I then decided to disconnect the wastegate line from the N75 valve and try again....total success, it pumped right up to .08 + b and stayed there. So, reflecting, I am going to replace, the N75 valve, the change-over valve and both diverter valves. I'm super happy that I confirmed the turbos were capable and the controls are just not doing what they should. Hopefully the bastard computer is not interfereing and limiting boost, if that's it I'll have to go down that road. Anyway, here's a couple pics of how to confirm diverter valve are working. Tim
