No Compression on # 2

[Justin Imperial]

Hi, so I haven't had a chance to formally introduce myself yet.  I bought my first car just 3 months ago. Its A 1991 Galant VR-4. Its a Turbocharged 6bolt 4G63.  The motor was rebuilt just recently and has about 10,000 kms

- Wiseco 9.0:1 Compression Pistons
- Cometic Head Gasket
- New Main Crank Bearings
- ARP Head Studs
- The Head was Pressure Tested
- 16G Turbo
- Apexi AFC neo
- Apexi AVC-D Boost Controller

Anyways, when I got the car I had problems boosting over 10psi as it just kept sputtering.  Finally checked my spark plugs last week and noticed that it was gapped @ .50, changed it to .28 and I can happily boost 10 psi.

Just a couple of days ago, coming to a light it was idling very rough. Sounded like a wrx and was problem only firing on 2 cylinders.   Pulled over and noticed that # 2 plug wire popped out a bit.  Tried to remove the spark plug as I suspected that it wasnt firing but it was seized!  Towed the car home,. .  After some patience and wd40 I was able to get the spark plug out.  Threads were fuzed, and the the top was completely gone.  It looked like it just melted.

Ever since after replacing all the plugs the idle still has been very rough.  So far I've:

- Replaced all plugs
- Replaced Coil Pack & Plug Wires
- Checked MAF
- Checked ISC
- Replaced fuel filter
- Checked ECU (see photo below)

I think my spark issues are fixed, and now thinking it may be fuel related as the narrowband gauge shows that idles lean.  

Any other ideas on what to check?

[Justin Imperial]

Spark Plug:

[andrew volcz]

If you have acess to an obd reader, you could view your vitals at a glance to see if a sensor is not cycling properly.  It could be as simple as dying primary o2 sensor.

[Justin Imperial]

Ya no ODB reader, unless anyone knows of a place that rents them out?

I checked the ECU. looks brand new and the caps look fine.  However, one of the daughter boards there has quite a few burned marks around the connection.

[Brett Haviland]

start with a quick compression test...  if u have a good miss at idle, consistantly, it should not take long to figure it out.

fuel/air + compression + spark = bang... as long as its timed correctly....

but looking at that plug being so melted, and the others were fine... (hard to tell cuz its out of focus, but i can see your pants, shirt, screwdriver, oily shop towel, dog (thanks for keeping your dog tied up, and not roaming the streets eating childrens blow up pools/toys btw), coffee cup, michelin  tire (minivan??), grv4 engine bay, driveway quite well)...................................Id say you have a bad injector/wiring probably.

[Justin Imperial]

Bad news. Just did the compression test

1 - 190
2 - 0  
3 - 190
4 - 190

Heres a pic of the plugs 1-4 left to right.  The # 2 plug is completely clean.  Used a stethoscope to check the injectors. All of em were clicking and seemed to be working.

What do you guys think... Bent Valve ?

better focus from the phone

[Jason Harwood]

Bad news. Just did the compression test

1 - 190
2 - 0  
3 - 190
4 - 190

Heres a pic of the plugs 1-4 left to right.  The # 2 plug is completely clean.  Used a stethoscope to check the injectors. All of em were clicking and seemed to be working.

What do you guys think... Bent Valve ?

better focus from the phone

Could be a bent valve. Could be rings.

I'd pull the head off just to make sure now.
You're going to want to see that cylinder and valve in the open.
If you're not blowing blue - then its valve.
If you're blowing blue - rings / piston.

If its just a valve when you open it up. Replace valves and make sure your timing is spot on.

[Justin Imperial]

Could be a bent valve. Could be rings.

I'd pull the head off just to make sure now.
You're going to want to see that cylinder and valve in the open.
If you're not blowing blue - then its valve.
If you're blowing blue - rings / piston.

If its just a valve when you open it up. Replace valves and make sure your timing is spot on.

Thanks for the reply!

Its not blowing blue.

If its just the valve, do I have to take off the head, or can I just do it by taking out the cams and the valve cover

[Brett Haviland]

Prob not a bent valve... But more like a burnt out valve.


You have to remove the cylinder head to replace a valve.  Better figure out what caused it to burn up in the first place tho, so it doesn't happen again after u fix it all!!

[Justin Imperial]

Prob not a bent valve... But more like a burnt out valve.


You have to remove the cylinder head to replace a valve.  Better figure out what caused it to burn up in the first place tho, so it doesn't happen again after u fix it all!!

Good point. If you look at the new spark plug. Its completely clean.  could it be possible that it was not getting any spark at all?

[Brett Haviland]

Well if it had 0 compresiion then ur not going to get any "bang" in that cylinder...  The fuel will just wash the plug down and it will look nice and clean

[daniel Dee]

Just a couple of days ago, coming to a light it was idling very rough. Sounded like a wrx and was problem only firing on 2 cylinders.   Pulled over and noticed that # 2 plug wire popped out a bit.  Tried to remove the spark plug as I suspected that it wasnt firing but it was seized!  Towed the car home,. .  After some patience and wd40 I was able to get the spark plug out.  Threads were fuzed, and the the top was completely gone.  It looked like it just melted.

Bad luck on number 2 cylinder....If it is bent valve (or burnt) you may want to check test that valve spring.
I strongly suggest you put anti-seize on your spark plugs.

[John Hartman]

before you pull anything, do a leakdown test!

If its leaking past the rings, you need to do the rings and hone, if its leaking past an exhaust valve, you just have to pull the head and have the valve(s) replaced.  Of course you have to pull the head to do the rings anyways, but you can plan better if you know what you are doing ahead of time.

If the valve is burned and at those low boost levels(unless regular gas??), I would be suspicious of whoever put that head togeather.

Or, possibly a sticking/poor pattern injector was causing super lean on that hole.


Mine blew on #2 as well.  Took a chunk out of the piston right thru the upper ring land into the inside of the piston.

Oh, just had a thought, most times burned valves only give a very low compression reading, not a 0.  Leads me more to piston/ring damage, but it still could be 0 if both valves are more than a little burned.

And change the oil as it will have lots of fuel in it

[daniel Dee]

x2

[Brett Haviland]

i have burned several valves out, on honda's and my champagne talon once.   All the times the compression tests netted 0 psi.  the gauge didnt even move at all!