S4 mulitple issues

[pilla]

Hi all, purchased a barn find S4, free'd all the callipers and did some repair, sealed up the leaky exhaust and wrapped the split flexi section, It was in limp mode, somebody had put the n75 and the other one next to it mixed up, fixed that, ran good, took it for a run, G66, knock sensor 2 code, pulling power, replaced the sensor, (wiring had rubbed through on block) pulls better now, but still its holding back, it boosts well initially but then it tails off, did the n249 bypass, slightly better feeling, but still the same problem, n75 seems to be ok, im thinking the wastegates at this point as the diverter valves are brand new 'go faster bitz' ones, (unsure of correct way round fitment though!) if anybody can help me with that one.

Then it throws a low voltage code, when i put the lights on and the heaters, it drops to 7 volts and wants to cut out, idling, with everything off, its giving 10-11 volts on the gauge, Would a bad alternator cause power to tail off up the rev range? Managed to get it to 130mph but it wouldnt go any faster than that at all. Engine itself seems strong and the boost is all there down low, (did a boost leak test) holds 15psi no problem, at that point the oil pan starts to bubble via the turbo seals.

Can anyone point me in the right direction on what to do next, im going to test wastegate cracking pressure next, but after that, im a bit stumped, fual filter change maybe?

Many thanks. Pilla.

 

[S4 Muzza]

You need to get the car scanned for starters, you’ll waste a lot of time and money if not. Come back with some fault codes and take it from there.

Also there is no benefit to ‘upgrading’ the diverter valves on these. Best to stick with a set of standard 710P’s. They’re only about £40 a piece and plenty of people running them on big power B5’s.

 

[pilla]

You need to get the car scanned for starters, you’ll waste a lot of time and money if not. Come back with some fault codes and take it from there.

Also there is no benefit to ‘upgrading’ the diverter valves on these. Best to stick with a set of standard 710P’s. They’re only about £40 a piece and plenty of people running them on big power B5’s.

Hi muzza, i did scan it, i have vagcom here, the diverters were on it when i bought it, they are brand new and 120 pound a piece, i did look at them and they look quality items inside, the 50 mile run ive done in it has drained the battery, if i put the lights on, the aircon and the window down at same time while idling, the voltage drops to 7 volts on vagcom and the car stumbles and struggles to stay running, i think my alternator is knackered, limiting the electrical load needed for high engine rpm, keep getting the low voltage code now, no other codes. Thanks muzza.