I noticed my car losing significant power past 7k rpm. The cold winter days of Kansas had just set in, and being my first boosted winter I figured it was my spark plugs, and didn't worry about it and just drove the car normally until I could go grab a set of colder plugs, which I needed anyway. I went to take out the old fouled copper plugs and noticed that in cylinder #1 the plug was loosened about 3 to 4 rotations from seal. Knowing that this could possibly have very adverse effects on air/fuel mixtures I immediately did a compression test to see if anything got burnt up. Test results are #1:210, #2:240, #3:240, #4:240. I had done a test before boost to make sure everything was in order, and it tested perfect 240's across the board. So it did some damage somewhere, and I don't know how long I was driving it like that either, because I never really run my car hard when daily driving. So I just need input as to what could have been damaged to cause this loss in compression, and could it possibly get worse?

-Jordan

 

Just put the plugs in and drive it. Torque plugs to 21 ft lbs.

Watch the compression and if it continues to fall then follow up.

The fact the plug was working loose can not be related to the compression.

 

Couldn't agree more. Torque it back up, then grip it and rip it.

 

So you guys just think it's a coincidence that the cylinder that has compression loss is also the cylinder that had the loose plug? Chalk it up to the tuner that put the previous plugs in. I always torque mine!

 

Now I really don't know what is going on. The car is still falling on its face at about 7k rpms. I'm thinking it might be a tuning issue now. I wish I had a wideband gauge to see what its running in this freezing weather.

 

Was any part of the number one spark plug missing?

A loose plug causes the cylinder to go way lean and get the plug hot enough to melt into the cylinder and damage it.

 

You could tell it was hot. The insulator was bubbled and there was white soot-like powder over the electrode but other than that everything seemed in tact.