PLEASE HELP!!! No compression in cylinder #2. Possible causes and solutions???

[blackbean2000]

Hello Everyone,

I am new to the forum and I am wondering if anyone could help me out here.

I completed an upper chain job on the engine a couple weeks ago on a 2000 GTI w/2.8L VR6 and got the following codes from the vagcom after getting her started:

16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 -
16686 - Cylinder 2
P0302 - 35-00 - Misfire Detected

So I took the spark plug out and saw that it was wet and had no signs of sparks (no marks, new plugs). I thought it was the fuel injector's fault for not spraying correctly, since there was a pool of fuel in the lower intake manifold for cylinder #2. Got the new fuel injector today and installed it, put everything back together and the same problem occurred. This time I bought a compression testing tool and found no compression whatsoever in cylinder #2, while the others were around 150psi, so the cause of the misfire is lack of compression.

I am thinking that the root cause could be the seals for the pistons are leaking or the valves aren't closing/sealing. I believe it to be the latter since there is no compression at all. If it were the pistons it would be low compression instead of none at all, at least I think.

When I took the head off the engine block I made sure to check that the all valves were closing and opening properly, but is there a chance that the valves are not okay even though they look fine outside?

Please offer me some advice or your opinions.

Thank you,

Blackbean2000


P.S. I did replace the head gasket with a new one.

[TBT-Syncro]

if the compression was zero, i doubt it was done properly.

there is nothing about the upper chain job that would cause that cylinder to fail.

start by re-doing the compression test.
then verify spark and fuel at that cylinder.

[Scotty_2.0]

I've personally seen cylinders produce zero or close to zero compression results after running so rich (either too much fuel, or no spark) that the oil was washed from the cylinder walls and piston rings. Sounds more like an ignition problem. Could be as simple as a bad or poorly connected spark plug wire.

[blackbean2000]

Hi TBT-Syncro and Scotty_2.0,

Thank you both for answering my post!

Well, I did do another compression test and it came out the same. I also checked the spark on the plug using the wire and it did spark. I even removed the spark plug after starting the engine up and some smoke came out of the hole. It seems that it is igniting and fuel is burning, but not efficiently. Really, I have no idea what is going on. I might have messed up the installation of the head.

Scotty_2.0, I did use seaform to clean the piston heads, would that be a possible source of the problem? The oil could have been washed away from that. Though, I did oil up the cylinders before putting the head on. Maybe I didn't put enough in that cylinder?

Anyways, I will probably take it in to get some professional help and get the cylinder examined if I can't figure it out.

Well, if you guys have any other ideas on what is going on, please let me know.

Again, thank you for your time.


Blackbean2000

[Scotty_2.0]

You should try getting a little oil in the cylinder with the low comp (very small amount like a teaspoon or less). You can use a straw or something similar to get oil onto the cylinder walls. Usually best to rotate the engine so that the piston is near the bottom so you have a better angle to the cylinder wall. Also, when you do the compression test, I suggest disabling the ECU somehow. On older 12V's I would pull the ECU relay, but I don't think you have one on the mk4. I would suggest unplugging the crank sensor or something. This will ensure that the injectors do not spray anymore fuel into the cylinders which could mess with your readings.

Also keep in mind it's very likely that the plug wire itself is the reason for the misfire as not much else would have changed. Wires that have been untouched for a long time usually don't like to be disturbed and can break inside when moved.

[Holmes741]

For the compression test, pull the fuse for the fuel injectors. I feel that having no compression is where you need to focus your effort, the fuel will not ignite if the concentration is not high enough.

[H2OVWRacr]

if you've tested it multiple times and it has no compression at all, then it sounds like mechanical damage to one of the valves....either a bent valve and/or a broken valve spring. i've never seen a washed out cylinder have no compression at all. you could do a leakdown test to verify this, but i would say you're most likely gonna have to pull the head back off. Since it's cylinder 2, it's also possible that the cam snapped between cylinders 2 and 4. It's an odd thing to have happen, but I've seen it before.

[HavokRuels]

1) It's pretty straight forward, OP stated that he tested all 6 cylinders and the problem cylinder yielded no results so obviously tests were done correctly.

2) Irregardless of FUEL and SPARK issues, neither of the two are required for a compression test.

I'm leaning towards internal issues

[Scotty_2.0]

i've never seen a washed out cylinder have no compression at all...

I'm not telling Internet gossip stories. I've witnessed it first hand. IT IS POSSIBLE.

Regardless, it's just one possibility. Next step would def be a leak down, they never lie.

[blackbean2000]

Hi guys,

Sorry it took me so long to get back to all of you. Been busy working with the car among other things.

First off, I want to thank you all for taking your time to help me solve my problems. Thank you so much!

Alright, down to business. I finally got the car fully functional today and put back together, for the exception of exhaust leaks. Man does it purr! So the cause was actually a bent intake valve in cylinder #2. I took the head off and saw that it was wide open and bent pretty badly. I replaced the whole head with a salvaged part from the local used auto parts place. It was totally my fault that it bent. My first time doing this type of job ever (changed the upper timing chain), so disaster was bound to happen. Don't know which moment exactly, but I believe it was bent when I put in the head and torqued the head bolts on with the pistons in the wrong postion. Anyways, learned my lesson on the second go round. Probably, gonna learn how to do a head rebuild now so I have a spare just in case.

Cheers guys! Thank you so much again!

Blackbean2000

[HavokRuels]

Congrats! Sometimes it's easy to over think a problem but frm your very 1st post, you did everything correctly and essentially answered your own question.

Cheers


Sent while sitting on my ass VIA my iPad