And new viton valve seals.

AFC arrived today. Tomorrow is installation and tuning, along with new plugs. I'll keep this thread updated.

Update?

Soot that wipes off is rich fuel.

This may make perfect sense.

Here'* the score:


Started it up this morning to go get new spark plugs, and it was running smooth. Shut if off at the parts store, went inside and made my purchase. Upon returning and starting it up again, it was misfiring on #3, which is the same cylinder that was dead the other day (when the plug was black). I took it over to my buddy'* and we changed the plugs back to Autolite 605s, and I thought it would cure the misfire, but it didn't. We switched plug wires and then switched coil packs, and it kept misfiring on #3 the whole time. We still tuned the AFC to keep the LTFT from being so lean in the lower and middle ranges, but the misfire never went away.

So, we figure it could be a bad injector O-ring, a bad injector, a faulty injector driver, or something worse like a head gasket leak on #3. The interesting thing is that I experienced a few misfires before we did the cam & heads, but I never knew which cylinder it was on. Based on Bill'* info, the injector may be stuck on and over-fueling the cylinder, but I'll have to get a noid light to check it out. I haven't checked the oil level for a couple weeks, so after the car cools down I'll go take a look to see if it has lost any oil.

At this point I'm just a little frustrated with this thing. I hope I only need a new injector, or maybe just a clean-up job on my old ones. Let me know what you guys think.

I'll list AFC calibrations at a later time. I can't remember all of them at the moment. We didn't finish tuning the car, as it seemed silly to fine-tune it while it was misfiring.

Turn on your brains, boys and squirrels! Please ask for any details I've failed to include!

Oi! Get a noid loight!

I don't have much time because a vibrations & controls project is killing me right now.
A couple things though.
When you were doing your rebuild I saw a pictures the injectors face down on the ground. So, something on the ground may have messed up the tip. Try switching the injectors. It'* pretty easy if you've never done it before.
Also, try getting a compression test.

I know you lapped the valves, however, since you had previous problems with the same cylinder, you may have a bad valve. Do a compression check on the cylinder and also listen to the exhaust. If you have recession on eother the valve face or the seat, it does not matter how much you lap the valve, it will never seat.

Also, how did you break-in the cam??? If the cam is not broken properly, you can easily damage a lobe. A compression check will also tell.

Well, we didn't really break in the cam by any particular process. We cruised it under light throttle, then gradually got more aggressive after a few miles and eventually did some WOT runs.

Let me say this, though. At first I was scared that we had internal problems, but this is a misfire that comes and goes. If a hard part was broken or something was not sealed it would misfire continuously. However, I had misfires before the work was done. The car ran smoothly for the first few hundred miles, then misfired again a few days ago. Again, the misfire went away for the last few days, then mysteriously came back again today. These symptoms seem indicative of a troublesome injector or injector driver, or a problem with my ICM. From what I can tell, a broken part or leaky seal would cause a condition that would permanently affect performance.

This is my thought process so far. Please correct me where I am mistaken.


EDIT: I just checked the oil, and it'* as full as the day we finished the cam swap. NO OIL LOSS! Let me tell you, I'm breathing a little easier after knowing this!

When you changed the plugs, did you take note of thier colors? For instance, was that #3 plug different from all the rest?
If you had a problem in one cylinder, the plugs should tell you that.