Chasing Knock

[Rugby]

I am chasing a knock on my car. I have the boost turned down to about 8lbs and still have a knock that I can hear. It does not happen ever time. When it happens I the car will lose power because it is pulling timming.

I do not have a scan tool yet.

The mods on the car
87 Grand National
Turbo Tweak Chip
36lbs Blue injectors
3" Down Pipe.
Kenne Bell 2.5" Exhaust with some type of turbo muffler
Adjustable Fuel Reg
Hot Wire Kit

Things I have done
Changed Plugs and Wires
Cleaned the MAF
Set Fuel Pressure at 43lbs
Set the TP Sensor
Checked for vacuum leaks

Tonight I pulled the Cam Sensor to look at it. It looks OK.
I pulled the plugs out to check compression. They were all between 135-145. This was on a clod motor with the throttle open. So that good.

That got me to looking in the cylinder to see if there is carbon built up on the cylinder. There is some carbon on them but not much. How much carbon build up is to much on the pistons to cause a carbon knock?
Would you use SeaFoam or the GM top Engine Cleaner on them and let it soak?

What are some other items to check before I can get a scanner?

Brandon

 

[Boostian]

Everyone is going to tell you to get a Scanmaster and post the numbers.
Then:
What boost gauge are you using?
What are you using to read fuel pressure on the go?
What else is done to the car?
How do you know it's knock and not a bad plug/wire/coil?

 

[Rugby]

I have a boost gauge on the a pillar that I have compared to a certed span gauge and it's pretty close.

The fuel pressure gauge is on a hose that I have put on the windshield so I can see it.

I has had the knock since I bought the car last year. I have put plugs and wires on it with no change.

I am going to buy a power logger when I get the extra cash.

 

[Rugby]

I do have a set of comp 980 valve springs for the car but I have not had a chance to instal them yet.

 

[Boostian]

Do you have a scanmaster? Where is the knock happening and how much KR?