Blackened spark plugs -- What's this signify?

[DC Turismo]

So since swapping in a fresh motor back in March, my Daytona has been running like a dream compared to the previous turbo motors (a beat one from previous owner, and a dud I installed last year that didn't last long).

I go to leave the house tonight and get to the end of my driveway and the car just bogs out and the motor shuts down. Try to start it again, and same deal. Only keeps running if I tap the gas or hold it in and it runs accordingly.

My dad came out and had me pull the spark plugs and they were as dark as charcoal on the bottom. Pat seems to think that this signifies my motor is running rich, but why would it do so all of a sudden? No changes have been made to it whatsoever, though. All in all, whatever this does signify, how can it be fixed?

The engine is a 1990 2.5 with a rebuilt Garret turbo, SS coolant lines, IC'd, a/c not charged yet. All fluids checked out OK.

Any help is appreciated. I cleaned up the spark plugs, put them back into place and after a few tries it started back up and ran fine over to my girlfriend's house.

Thanks in advance./

[cordes]

How do you know it hasn't been running rich?

[t3rse]

if their slimy then bad blow-by, but blackened and sort of crusty means its been running rich for a while, which will lead to bad blow-by...

[ShelbyMotorsports]

It's running pig rich as they say.

What spark plugs are you using? Sounds like you need a hotter plug.

[Captain Chaos]

When my MAP hose fell off it fouled a set of plugs in a matter of minutes.

[DC Turismo]

I would think it hasn't been running rich since I've pulled the plugs a few times between March and present day to check things out and also to hit 'em with a wire brush to ensure they were clean.

I'm using the Champion sparkplugs, not sure on an exact model number though.

They were not slimy when I pulled them out though, they looked crusty like charcoal.

[Captain Chaos]

http://www.gnttype.org/techarea/engine/plugs.html
Their pics aren't the greatest, but you get the idea.

[ShelbyMotorsports]

They were not slimy when I pulled them out though, they looked crusty like charcoal.

Running rich doesn't mean a wet looking plug. Running rich will be a dry charcoal coating that is failing to burn off during the combustion process. Check what plug you are running and we can go from there.

By the way Champion spark plugs are cheap enough that you should just replace them instead of wire brushing them clean.

[DC Turismo]

Gotcha. But what do I do about 'running rich' then? I do not have an AFPR, and would prefer not to buy one either at the current time. Any thoughts?

[GLHNSLHT2]

is the ECU stock? Sounds like a cracked map line. My GLH would blow the line off the baro solenoid under spirited driving and would barely idle and turn the plugs black instantly. Also maybe the Baro solenoid is sticking open. I've seen that before too.

[azkcar135]

i'm having the same problem and still haven't figured it out. is your car smoking at all?

[magtec]

+1 for the MAP sensor issue

[DC Turismo]

No smoke here.

No holes/cracks in the vac. lines to the MAP either.

[Captain Chaos]

Are they all black? Maybe a hung injector. FPR reg bad dumping fuel?

[GLHNSLHT2]

if they're black it should be puking black smoke out the exhuast. Cap off the vent barb on the baro solenoid and see if it goes away. Also did you check everything with a mityvac to make sure the lines are good?

[Dodgeglht]

O2 sensor issue possibly, worn cap & rotor maybe, spark plug wires, even a fuel system problem can cause rich conditions.

[bfarroo]

Make sure the wires to the O2 sensor didn't come in contact with the power steering pump or exhaust and break/melt. Do you have a scanner to check what your map is actually reading? Possibly swap a know good sensor in to test it.

[LaserXT1986]

Billy, check the following:

1.) Hook up a fuel pressure gauge to the valve on the fuel line, unplug the regulator, and look at the reading (with the car running). I believe it should be 55psi on a stock setup (anyone here correct me if I am wrong). If the lines to the reg are bad, or the reg itself sh!t the sheets, this will cause it to run pig rich. I have a few laying around that are good if you need one.

2.) O2 sensor....check the wiring, check the codes, and lastly, how old is it?

Those are things that used to cause my old setup to flood the car with fuel when they went bad. Just a thought....

[DC Turismo]

Thanks Dave, I'll def. do that tonight!

[DC Turismo]

I didn't get the chance to test out the fuel pressure, but after hooking up the A/F gauge and taking it for a test drive, it bounces from all red to orange to yellow two blocks into the green as a whole back and forth in a steady lit format when driving. If accelerated and boost is over 4 PSI, two bars of green (rich) show up. After letting off of the accelerator, it drops down to two bars of red for a second or two, then back up to the steady bar. Does this sound as if the gauge is reading correctly and if so is my car running accordingly?

Fuel pressure will be checked tomorrow though. Could not get my hand in there because the engine was still hot from sitting in the heat and driving 100+ miles an hour beforehand lol...

All wires to 02 are connected and appear to be in fine shape. 02 itself was relatively new, I'd say it hasn't been used for more than 20k miles? And again, still no codes!

I would like to buy new spark plugs, but should I just wait to get the fuel pressure fixed first rather than possibly have another set crap out?