Reduced Power

[prj]

Ok, Thanks, will post in wanted section for a MAF, is there anything else that will cause the ECU to fully retard the timing ?

Well, if the MAF signal is bad (too low or too high), then all ECU calculations will be wrong and your timing and fuelling will be totally off...

But if the load calculation is okay, then I wrote before in which three cases the timing is retarded.

[Dingo]

"FIXED" after the advice about the MAF I was offered a spare one, but whilst its been posted out I was just looking at the old one to see whats involed in the swap, I disconected the lead, had a look and put it back, and WOW, next time I drove it, I've got my old car back, It pulls hard and strong now all the way through the the rev range.
On closer inspection of this socket it looks ok, no corrosion or dirt but I cleaned it all out with contact cleaner anyway, there must have been a bad conection causing high resistance,
This all happened at the same time I had the new V stream chips fitted so Its the first time I've been able to appreciate how well they work, the car is flying now (thanks Paul) and I'm back in love again
When the MAF turns up I guess I'll have a spare one, but I'm just so happy its fixed.

[S2central.net]

Good ol' MAF plug nonsense... glad that's all it was... MAF input is pretty critical.

I must get some time to take some VAGCOM data runs as a guideline for what MAF readings to expect - say from 30 to 70 or whatever in 4th for example... That would help spot odd readings - even if the raw data coming from VAGCOM isn't readily scaled into anything meaningful - that is a problem for another day.

[S2central.net]

As an afterthought... this is a good example where Motronic safety routines have dropped back timing because of knock detection - presumably as bad signal from MAF was making it run too lean under high load. Chips which delete such safety routines would result in continued knock and potential engine damage.