Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Losing power on a diesel

I have noticed lately that my manual 2003 TDI Jetta doesn’t take off as fast as it used to. It will not go faster than 60mph up a hill even with my foot to the floor. Is it clogged up somewhere, or maybe a lose hose.

Change your fuel filter…

I did that this past spring when it was having problems starting. Could it be the fuel vacuum pump or the catalytic converter clogged up?

I would have the turbo checked. It might be beginning to show signs of age.

What converter? Only the 2010 models have converters (maybe)…

Is there a turbo boost gauge that lets you monitor the turbo?

i really don’t think there is a turbo, even though its called a turbo diesel. There isn’t a gauge on it for a turbo. ???

ok, I researched it and my 2003 diesel does have a catalytic converter. Actually there are two in one. One works the chemicals and the other one is for the fuel exchange. So Im pretty sure thats what it is.

The TDI diesel is turbo charged. There is a boost pressure regulator that is controled by the PCM. It appears the only way to check the operation of the boost pressure control is with a manufacturer’s scanner or a capable generic code scanner. It is possible that the waste gate is stuck open but that is integral with the turbo so you won’t be changing that on speculation.

You may need to run this by the dealership service department.

Check to see of there’s a urea tank for lowering NOx emssions. If there is, and you haven’t kept the urea tank full, the catalytic converter for NOx reduction is probably plugged up.


I have to ask…

Did you change the air filter?

Air filter. You don’t have a K&N air cleaner on it do you? Do you have a CEL? How about the MAF, it sounds like you may be in limp mode. Even when there is not a CEL you may have an issue that may not trigger it.

BTW the folk over at the [] can be a lot of help and there may be a member close by who is willing to give you a hand.

No urea on 4-cyl TDIs. Bigger engines have it.

Yes, it does have a turbo.