Guys,
My plugs are covered with heaps of crusty, black carbon buildup. Sometimes the exhaust spatters a black mist onto cement when its cold (only sometimes tho). It runnin' WAY rich. It starts and runs ok (no misfires or anything). But it could be a hellava lot better.
What could be causing this prob?
I have recently replaced a 160 thermostat with a 180, and i have one step colder than stock plugs in it.
I doubt these two things could be causing it by themselves...
The fuel pressure regulator is stock.
I have removed all emissions equipment, and have shorty headers.
I also have a walbro 255 pump in the tank (not the hi-press model though).

I discovered the prob when taking out the plugs today in preperation for a cam change from stock to Crane 2032.

Any suggestions?

 

Can you post a photo of the plug(s)?

 

Are you using the stock chip in the computer? Why are you using a colder plug? Can you test your fuel pressure? How fast does it drop after you shut it off?

 

Heres some pics that will help.

The real chunky one is the worst by far. Didn't check what cylinder it came out of. The other one is like the rest, dark and chunky on one side, white in the other. Interesting....flow characteristic of wedge head style chambers perhaps?

Yeah, stock chip. Goin to chase up some prom burning software and gear soon though.
I have flat top pistons (slightly higher comp), so i thought id run cooler plugs. In addition, the R45TS plugs (stock) are hard to get here. The R44TS ones are way more common.
I am prob going to get an AFPR and gauge w/isolator soon too so i can see whats happenin'.

Any ideas?

 

Two more.....

 

WOW!!!! How many miles on the motor? That looks to be oil burned on to the plugs.

 

looks like bad valve seals or bad guides.

 

How many miles on the plugs? Motor? Water the motor well, maybe even twice, swap plugs to the proper range, check timing and state of tune and maybe think on plat plugs. Oh yea, did I mention maybe do a nice comp and leakdown test while you're at it.

 

The engine has around 10000 miles on it. Rebuilt about 6 months ago.
Its running way rich.
The cylinder heads and valvetrain, are all stock spec clearances.
Timing is 0deg with trans in drive.

Would the 160 stat affect the plugs? Unlikely cause the 'cold temp richness' thing the computer would turn off way before that right?

 

Have the plugs been in there since the rebuild? Fix the richness problem, if it's really bad you may have washed the rings to hell. Ignore the thermostat. Then do what I mentioned in my previous post and throw up the results.

 

I would do a compression check on all the cylinders. I think some of the rings didn't seat.

 

Righto - timings at 7deg adv in Drive at idle.
Those plugs were in it since the engine was rebuilt. The newies look like they are heading down thre same path too.
I just did a comp test on number 1 & 2 cylinders. Cranking pressure was 175psi for both of them.

 

Ok, just put the normal range plugs in - ACDelco R45TS. I tested the fuel pressure, its 44psi at idle with no vacuum (vac line disconnected). The fuel pressure stays up when i shut it off.
Also i installed a Mallory AFPR, but the funny thing is the minimum pressure is same as stock so i cant experiment with a slightly lower pressure to help lean it out. If the warmer plugs dont help, i might have to get setup and earn prom burning sooner than later.

Are the above fuel pressure conditions considered normal?