conq2230 Posted April 6, 2013 Report Share Posted April 6, 2013 Can anyone explain to me why a bad vacuum advance causes a single stumble under wot? I have a black 87 TSI (161K miles) I bought new in 1987 which is now running great after I replaced the vacuum advance (2nd time in its lifetime). I've never quite understood why the vacuum advance causes the single hiccup around 3k and then continues to accelerate. Thanks Quote Link to comment Share on other sites More sharing options...
Guest Posted April 8, 2013 Report Share Posted April 8, 2013 The vaccuum advance does exactly that, advance timing at higher RPM's. There are more versed members here that can explain it better, but in plane Jane talk, it also has something to do with greater fuel demand upon accelarating past 3k. Quote Link to comment Share on other sites More sharing options...
conq2230 Posted April 8, 2013 Author Report Share Posted April 8, 2013 The single stutter is the thing I don't understand. Why just one hiccup where it feels like the fuel or current is shut off and then return to a hard pull. I guess I could undersand the bad va cause detonation and the knock sensor killed the juice or something. The actual mechanism of a single hiccup instead of continued bad performance is a mystery to me. Quote Link to comment Share on other sites More sharing options...
TexasQuest Posted April 8, 2013 Report Share Posted April 8, 2013 That's the timing advancing your feeling. It only does it once every so often when it needs to advance the timing, for instance when you got your foot into it. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.