#1
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Cold start - missing boost
So..
More and more often when I start driving the car from cold, I get no boost pressure. When I reach 60-70kph I get flashing glow plug light, limp mode (even less power than before) and fault code P0235. If I notice when I start driving that boost is missing, I can drive carefully on flat ground for 10 minutes without pressing the pedal too hard, no "limp mode" and no flashing light, just ALOT of missing power.. When the engine reaches normal temp, I can park it for 6-7 minutes to let it "shut down", then start and everything is fine. If I start from cold, even the times it drives normal, and then stop the car before it's completely warmed up, I will have no boost when I start it again. As long as the engine is warm, everything is fine. Always. Tried changing boost sensor and the plug, that didn't help. Turbo actuator maybe ? Outtakes from a few vcds scans I did some time ago, before I understood I had to let it "shut down" to start working again: Quote:
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06 A8 3,0TDIq My daily driver and project... 97 A4 1,8Tq. Powered by a 4,2 from the '01 S6, full rollcage, FIA seats and 6-point harnesses, B5 RS4 KW Competition race suspension, B6 S4 brakes, 18" Toyo RS1 slicks, carbon fiber roof. V8 trackday racer 14 VW Caddy 1,6TDI from my employer.. (X)00 A8 2,8q, (X)97 A4 1,8Tq, (X)92 S4 2,2Tq, (X)92 80 2,3E |
#2
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Is vnt turbo vaccum or electric control ?
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#3
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Any ideas ?
Turbo has the electric vnt unit/actuator.
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06 A8 3,0TDIq My daily driver and project... 97 A4 1,8Tq. Powered by a 4,2 from the '01 S6, full rollcage, FIA seats and 6-point harnesses, B5 RS4 KW Competition race suspension, B6 S4 brakes, 18" Toyo RS1 slicks, carbon fiber roof. V8 trackday racer 14 VW Caddy 1,6TDI from my employer.. (X)00 A8 2,8q, (X)97 A4 1,8Tq, (X)92 S4 2,2Tq, (X)92 80 2,3E |
#4
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When you start it do you see vnt mechanism get pulled over one way , when you blip throttle do you see vnt mechanism do a little flick
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#5
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In hook the actuator arm off the vnt and ensure turbo vanes move smoothly and freely
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#6
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The linkage moves smoothly, and the spring in the actuator pulls it back fine.
I haven't inspected what happens when i start the car, but since it works fine when everything warms up, I guess that points to something not right inside the actuator electronics.. Anyway the turbo has done 200k km, so maybe it's life is almost over..
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06 A8 3,0TDIq My daily driver and project... 97 A4 1,8Tq. Powered by a 4,2 from the '01 S6, full rollcage, FIA seats and 6-point harnesses, B5 RS4 KW Competition race suspension, B6 S4 brakes, 18" Toyo RS1 slicks, carbon fiber roof. V8 trackday racer 14 VW Caddy 1,6TDI from my employer.. (X)00 A8 2,8q, (X)97 A4 1,8Tq, (X)92 S4 2,2Tq, (X)92 80 2,3E |
#7
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The last few days I have also gotten code P3348, so definitely something not right with the turbo actuator..
Today I connected the laptop when I drove off, and I see that "specified boost" works and "actual boost" is pretty much zero. Also, the boost regulator duty cycle is stuck at 16%.. Later when everything was fine, the duty cycle varied between 20-80%.
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06 A8 3,0TDIq My daily driver and project... 97 A4 1,8Tq. Powered by a 4,2 from the '01 S6, full rollcage, FIA seats and 6-point harnesses, B5 RS4 KW Competition race suspension, B6 S4 brakes, 18" Toyo RS1 slicks, carbon fiber roof. V8 trackday racer 14 VW Caddy 1,6TDI from my employer.. (X)00 A8 2,8q, (X)97 A4 1,8Tq, (X)92 S4 2,2Tq, (X)92 80 2,3E Last edited by peiiider; 15th August 2017 at 09:48 PM. |
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