2000 tdi alh low compression #3

hey guys, got a question for you.
I have a 2000 jetta with 202k on her, its a 5 speed, no mods just picked the car up and did the injectors, new timing belt etc. Car turns out has low compression on number 3 cylinder, i did 3 compresson tests and came up with close (within 10 psi) each time. did hot cold etc. 1= 450psi, 2= 450psi, 3= 390psi, 4=455psi, this number 3 is making the car smoke and shake and mis at idle and it used to throw a code for cylinder 3 misfire but after playing with friends com and adjust timing, new injector nozzles pop tested its still here and car is bad when its cold.
I checked the turbo and tubes for oil and none
I have pressurized cylinder 3 and hear no noise out exhaust or intake (but didnt listen to the crank case to see if rings leaking.)
I have not checked to see if intake is clogged, i did clean egr and antishudder valve.
I did not throw oil in chamber to see if number rises but should probably do that.

Ok throw some ideas at me, if need be can i pull head ( get resurfaced, new gasket etc) and bore out #3 and put oversized rings in it to fix the problem if its the rings. Should i drive the car and see if a ring is stuck, car was not taken car of by previous who only had it for 4k and front end collision bu tjust hood and grill damaged and radiator.
Is it possible a ring is stuck, what oil would you throw down cylinder?

where is best place to buy good, cheap, piston, rings and stuff.

thanks in advance
John

If you find nothing wrong in the valve train, I'ld put money on a bent rod.
It would be unusual for rings/etc to be bad in just one hole.
Runaway or hydrolock in history the typical cause.

I agree with jetta wreck, sounds like a bent rod. Pop the head and use a dial indicator and check the protrusion height of each piston. I bet #3 won't be as high as the rest.
It's only gonna cost you some gaskets , bolts and time if you are doing it yourself.
If you need piston rods contact franko6. My .02.
Btw where in Northern N.J. are you located.

SLOW DOWN>>>> before you start tearing into a motor needlessly.

Think about it for a second... if the previous nozzle was bad and was causing excessive soot formation (mis-fire, poor atomization etc), the rings are more than likely jammed up from soot.

This is the same that occurs from lugging a motor, the rings can't cycle in the land and they jam up.

I'd say give it a week or two of firm driving, and re-test the compression to see if it is coming back.

It can't hurt and would give you a better idea as to what the next step would be.

csstevej said:

I agree with jetta wreck, sounds like a bent rod. Pop the head and use a dial indicator and check the protrusion height of each piston. I bet #3 won't be as high as the rest.
It's only gonna cost you some gaskets , bolts and time if you are doing it yourself.
If you need piston rods contact franko6. My .02.
Btw where in Northern N.J. are you located.

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yeah i was thinking rings or bent rod, i dont have any history on the car really, turbo doesnt look brand new but it is definately not original and car has 202K on it some like that so maybe the turbo let go and started to run away and either hydrolocked it and shut down or previous owner shut it down or a little of both. I figure after you buy something maybe the prev owners would tell you what really happened but maybe not lol.
i live in towaco, nj exactly. not my first tdi ive worked on so getting around the car is not a problem just didnt want to rip it apart and do a rod, considering i just did the belt on it when i got it but learn from mistakes.

DRIVE..: i agree with your ideas, As for the injectors, they were shot, craig at fairview diesel did them for me and im not sure if the number 3 was causing the issue to carbon up the rings and maybe its just stuck like you guys said. i guess i will drive it for 3 days and see what happens and go from there, hopefeully ring will free up and will be good to go.
But on worst case scenario. cyl 3 is scored or something. what are my options. can i just hone out number 3 in the car and put over sized rings in it? can you sleeve a tdi alh motor? where should i get piston rings and stuff from any repuitable people you recommend?
thanks guys
John

Without knowing the history it is hard to tell what the cause is. I sure wish there was a jig you could use to test piston pertrusion using the inector hole.

I also would like a boroscope that would fit down those holes so you could look around.

Would be nice if people told the end of their story with tdi problems