Anyone good with diesels ?
I'm only getting 30-32mpg around town from my '99 Passat tdi. It's a 90hp model with a tuning box fitted (unknown make but looks like an Alpin, mpg unchanged when originally fitted).
Mpg has been fine till the last couple of weeks, noticed how quickly the gauge has been dropping (compaired to normal) and carried out a proper (brimmed tank) mpg check.
First check with mixed town and by-pass use (75mph cruising for around 60 miles) came out at 34mpg, followed by two town checks at 30.8 & 32mpg.
Driving is mixed stop/start (i.e town traffic rather than being swithed on & off all the time) and not much over 45mph average. I dont drive foot to the floor, I let the turbo spool-up and do the work using about a 1/3-1/2 throttle tops.
The MFA shows between 39-42mpg around town and mid to high 40's on by-pass and A-road work, but it's certainly lying at the moment.
The car gets regular service work (oil & filter 2k ago, air filter 6k ago) and recently passed it's M.O.T smoke test with flying colours. It pull's well and will easily pass 100mph if asked (of course that could be kmh officer ! ), it does'nt smoke heavily, stutter or have any flat spots or dragging brakes that I can feel.
It is a bit miley (226k) but runs fine, never had the head off, original cat, exhaust, turbo, injectors etc.
My initial thought was MAF (it's never had one) but it pulls fine and revs round to over 4k without any hesitation (I dont rev past that much due to not being necessary and in defence of the milage), or maybe coolant temp... temp gauge gets up to temp quickly, though I have had it fluctuate slightly in the past.
Just done another check today, 52.89 ltrs (13.97 gal's) in 473 miles, 33.86 by my Casio, that includes a fair bit of "swift" A-road work (about 100 miles worth) and is consistant with my earlier findings.
Any ideas ?
Poor Tdi economy
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