Poor fuel economy

Dallas Stace-smith

Active member
Joined
Aug 27, 2020
Location
calgary Alberta
TDI
2003 TDI Jetta gls
I've got an 03 Alh Jetta with a Malone stage 1 and sprint 520 nozzles and a cat fuel filter. I've been doing pretty much only town driving lately but my fuel economy went from 5.9 L/100 to 8.9 L/100 and I'm just wondering if anyone could shed some light on maybe why this happened. I may have a clogged injector but I'm not sure I haven't got injector cleaner yet. Or I'm also thinking that the town I live in especially in the winter there could be a little water on the fuel or condensation in the tank that is getting into the fuel because the cat filter unfortunately doesn't have a water separator but I don't know for sure about either.
 

krook

Member
Joined
Jan 13, 2021
Location
Hungary, Europe
TDI
1.9 TDI AFN A4 B5
check your start of injection with vagcom and set mechanically if required.

also, the stock fuel filter does separate water.
 
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