Lower on power and down on MPG

[Alhambra King]

Hi guys, my older 03 Alhambra 1.9Tdi has started to act up. There are no fault codes and it still drives well but is deffinately lower on power then it used to be (not dead like a dodgy MAF) just less power. The MPG is now struggling to get above 40 and there is a stronger exhaust smell. It's also taking much longer to reach operating temperature when the aux heater isnt being used.
Wondering if it's a dodgy sensor or injector?

[Alhambra King]

Anyone?

[Chrispb]

Sounds about right for this time of year.

[Alhambra King]

Hi Chris thanks for the reply but I've lived with this car for the last 9 years so I know it's quirks. It's not normal for mine to never get to temp and even in -4 it still used to get mid 40s on MPG so somats up!

[brianh]

I'd wonder if your thermostat is open when it shouldn't be if its a noticeable change, could have been like that a while and not noticed it until the temperature outside has dropped, If its staying colder than it should it will increase fuel consumption. Only other simple cause that could come to mind is if the air filter is clogged up, though would imagine you've either already changed it or checked it at least. (would explain exhaust smell)

[johnnyroper]

Another vote for thermostat mine was like that post head gasket change. Turned out the thermostat was closed when I removed it to test and it opened at correct temp however it had gone weak so with water pressure behind it the stat would push off its seat. New thermostat fitted and even when boost heater was knackered warm up time was not much longer.

I would change thermostat and coolant,bleed system and then see how it goes. That would not account for the low power though.
Also check and clean EGR valve and check all vac lines make sure non are cracked.

[mike wilson]

Only other simple cause that could come to mind is if the air filter is clogged up, though would imagine you've either already changed it or checked it at least. (would explain exhaust smell)

I'm not sure that's logical on a modern, injected engine.  If less air goes in, the engine management system should detect that and put in less fuel.  There would presumably come a time when the combination of throttle position, road speed and sensed air flow would exceed parameters but that would have to be pretty high, considering all the lead-footed drivers.

[johnnyroper]

A clogged filter would still cause it to be down on power because actual fuel quantity compared to desired in relation to throttle demand would be lower.

[Alhambra King]

Thanks fellas,

The filter was changed at service around 3k miles ago but I will check it just to sure. Having chatted with the good lady I think its probably not down on power so much that I've just got used to the more powerful one I drive daily so its different to how I remember.

Will get the thermostat changed and come back to you. Thanks for the help thus far!