2003 VW Jetta TDI runs poorly

My Jetta has 417,000 KM and a compression test shows only 180psi compression, all 4 cylinders. Strangely, it still starts right off but makes lots of grey exhaust smoke when it is cold.
The past 2 years it has been used on all short trips, the engine is equipped with a webasto heater.
Some time ago, I read on here that these engines can lose piston ring seating in cases like this and I am wondering if I could obtain the post again..
The engine is otherwise sound, fuel injection timing has been checked mechanically and with the Ross-Tech interface. The injectors have new tips and VOP has been checked.

How was that compression done? Did you cranked until the gauge couldn't raise any higher? Is that compression tester trustworthy?

180PSI is very low, you might need to rebuild your engine. New piston rings.

You need a better compression tester.

oilhammer said:

You need a better compression tester.

Click to expand...

Yes a rule of thumb is nothing under 300 psi compression will work to start the car. On my RIP 2002 Golf all of the cylinders were above 500 psi.

Well, in my original post on here, I forgot to mention how the problem started. I took a short trip, 35km round trip but on the return trip I had to accelerate hard to avoid a collision. When I got home the engine had a loud ticking noise that it never had before. Later, I removed and decarbonned the intake manifold and intake ports. The carbon in the intake manifold was easily thick enough that if a large piece was ingested it would cause damage, to pistons, even causing a bent connecting rod. I believe that one or more pistons were damaged by ingesting large pieces of carbon. I sold the car as is.

Not sure why you brought this up again but since you did I'll say that if you got junk into the motor and bent things it seems very unlikely that you damaged all 4 cylinders identically so the compression's the same in all cylinders.

I agree with the bad gauge theory. Or improper technique.

Sounds like a stuck rings. I've had mysterious like this compression. My nighthawk I'm rebuilding had exactly 62psi on all 4 pistons. Even after taking the jug out and measuring it, everything was within spec, aside from egg limit. Also found all the oil rings were stuck gummed up.
Interesting how 3 years later this comes back up!