Spark Plug Fouling

[Nick M.]

I replaced my plugs this past weekend with the correct ones for my 63 FI Coupe for judging purposes and was quite surprised by how black and sooty the old ones were. They were only in the car about 2 years and less than 300 miles. Looking for ideas as to why they would be so soiled and what steps I should take to correct the problem. I assume it's because it's running too rich.

[David C.]

Re: Spark Plug Fouling

Nick, FI cars need to be exercised. (Some high RPM runs). 300 miles in
two years does not sound like enough exercise, especially if they were slow miles with a lot of starting and stopping. This could explain your black, sooty plugs. If the insides of your tail pipes are gray and not black, then your probably not running too rich.

[Nick M.]

Re: Spark Plug Fouling

Dave

Great hearing from you. Thanks for the tip on the high RPM runs. As soon as the weather gets a tad better I'll take er out for a jog around the neigborhood. Definitely will take a look at the inside of the exhaust tips. Take care and thanks

[Patrick H.]

Re: Spark Plug Fouling

What plugs did you remove (brand and heat range), and which ones did you install?

That might help diagnose your issue.

Patrick

[John D.]

Re: Spark Plug Fouling

Nick, FI cars need to be exercised. (Some high RPM runs). 300 miles in
two years does not sound like enough exercise, especially if they were slow miles with a lot of starting and stopping. This could explain your black, sooty plugs. If the insides of your tail pipes are gray and not black, then your probably not running too rich.

Wow. A post from Cardina. Wonder will never cease old friend. Let me use you to get to Nick.
Nick this discussion has been beaten to death a lot by a ton of the regulars here. But since you have a trailer queen like I do and don't drive the damn thing those AC44's ain't gonna cut it. Also if you are running a repro 091 coil and also the AC44 plugs, the dated spark plug wires, etc. you are in trouble. I would step up to a nice set of AC 46 spark plugs no matter what is said here and forget about it. How if you foul out those babies then you are in for some FI work.
Don't forget it could be a weak or bad cranking signal valve. That's the weak link in a 63 unit. Could be other FI problems also. What are you using for fuel Nick. Try some 100 low lead aviation fuel. A set of AC 46 plugs. Take the cranking signal valve off and send it to me. If you have an original Cranking signal valve rebuilt ones are available. But if you have a POC repro one then you are in trouble.
You unit was rebuilt a very long time ago. You could have vacuum leaks, out of calibration, choke problems, etc. Good luck. John D.

P.S. On page 103 of the new manual it states all cars have AC 44 spark plugs, etc. Nick if you have a nice origianl 091 coil, a nice set of original wires and the ignition is dead nuts, the FI is perfect, and the engine is in tip top shape and you drive the car AC 44's will last a long time. Few of the fuel cars are driven much and a lot are loaded with repro parts so therefore the AC 44's don't last very long. Use a nice set of 45 or 46 plugs and don't worry about the ding on the plugs. I mean if you fail the ops on idling etc. that is a huge 25 deduct. Call me if you want more info. Seven Spring is really getting close and my 63 is really apart. Hint Cardina. JD

[Nick M.]

Re: Spark Plug Fouling

John

It seems like the more I work on the car, the more work I need to get done in time for Seven Springs. Not sure there are enough days left for me to prevail ! I'll give you a call to discuss this issue in greater detail.