Quote:
Originally Posted by 20vcqdriver
Yes, considered that which is why I am taking it up and down the road late at night to get it as low as I dare before putting fresh in. Would not cause the 0.2 bar drop in boost however or limp mode to cut in.
Strange progress last night as I wound the wastegate spring in a full turn and on its trip out it did not go into limp mode, might be coincidence, but might be worth exploring further if same happens tonight... noticed boost very slightly higher too but that might be down to lower air inlet temps last night...  |
You could do with popping VAG COM on it. Has it still got the diag plugs connected?
Use measured value blocks (if ECU late engough to support them) to measure specified and actual boost levels. this would show any leak or at least that it is asking for full boost but cannot supply it. Also, check the N75 is working properly, I know you said a wire was broken but they can stick open if left for a long time, the ReCirc valve and it's control valve can do the same. These engines use the ReCirc valve as much as the N75 to regualte boost (it hasnt been replaced with an atmospheric dump valve has it??? - they're bad!) Also, ensure the diaphram for the wastegate isnt in bits.
I know it sounds obvious but if it violently cuts into limp mode under heavy load then double check for boost leaks.
Either an air leak or failed air mass meter could give the same fault as the ECU cannot correctly adjust fuelling if it "thinks" the wrong volume of air is getting in, same applies if the air mass has acounted for air being drawn in but it escapes before getting into the engine.