Spark Plug Appearance

[RRoller123]

What do these spark plug pics tell you folks about the tuning? Too Rich/Lean? Too Hot/Cold? The color didn't come through very well, but they are light tan in general. The ground arm is pretty heavily covered. Maybe 500 miles on the plugs since last cleaned. Gap .032" with a a Compu-Tronics ignition system. No gap wear noticeable, just curious about what the deposits tell us.

Thanks. Pete.

[phaetn]

I was told (by Mark Allison either on FS.com or pm/e-mail) to run a much wider gap with the Computronix: .045 gap. I have the first gen module (instruction manual for a Ford 2.3L engine). Apparently the bigger gap allows for a fat, juicy spark.

Also it has been suggested to avoid any of the new plugs with iridium, platinum or whatever. I run NKGs BPR6ES. They used to be sold as "for cars" now they're sold for lawnmovers and the like. Whatever, they're cheaper now than they used to be.

Colour looks fine to me. A bit more golden brown might be nice on the ceramic, but I wouldn't lose sleep over it. Is that wear on the tip?

Cheers,
phaetn

[RRoller123]

They are BPR6ES, and there isn't much wear on the tip. I had been using a wider gap in the past, but for the life of me I can't remember why I went back to the high side of the normal range, 0.032". (?) They are solidly tan, and they all look pretty much the same, so I guess I won't worry about it. They cleaned up well and the engine started right back up.

I did have a slight misfire across all rpm on my drive home from the Cape last weekend, so this is part of working out that issue.

[sptcoupe]

They look pretty lean to me. That might explain your misfire across the RPM range.

[RRoller123]

Easily could be. Someone along the way has been inside the AFM (well before I went and fiddled with it), so I can't say the spring tension is correct. Same with the bypass air in the AFM. I haven't touched the spring, but I have fiddled the bypass air. It may be time to send it out for a refurb and recalibration. I remember somewhere here there was a shop mentioned, on the West Coast I think, who does a worthy AFM refurb?

So.... plugs all look uniform in appearance, car has plenty of power, compression tests in the 145-150 range in all 4 cylinders, and all connections to the various FI bits have been checked and are working. AAV closes, no air leaks.....

But.... I do also wonder about the Charcoal cannister. This rarely gets talked about as an unpredictable source of unmetered air, but it has a direct line into the air plenum, and a lot of air flows through it with the engine running. The "metered" top is kinda a silly concept, that snap-in cap just sits there quite loosely and wiggles around quite a bit. So much for any accurate metering. Pull that cap and plug the hole with a finger while the engine is running and you can see that it pulls a LOT of air.

Question for the assembled masses: I wonder... as the charcoal canister ages, does the flow rate through it increase or decrease or stay the same? One would think that it would decrease as the charcoal gathers dust, etc. But it is also possible that the charcoal breaks down, some of it is carried away as charcoal dust, and that the flow increases, which would definitely lean out the mixture in the air plenum. I wonder....

Checking ignition timing today (hurricane here has made the last 2 days unsuitable for leaving the garage) I think I will also try a little AFM spring tension adjustment before I send the AFM out and see if it runs any better.

Also will check the O2 sensor activity with an analog meter today. It is nearly impossible with a digital meter to tell anything because the readings jump around so much. You basically just get some indication that it is either working or not. My guess is that my older analog meter reacts slowly enough that the needle swing will dampen and will effectively show an average reading, which is what we are looking for. (~4.5 VDC Right?, or is it ~0.45 VDC, damn... now have to look that up). I will let you know if this technique works.

[rjkoop]

Haven't called them yet but this was the place I was hoping to send mine to over the winter...

http://www.fuelinjectioncorp.com/
Phone: 925-371-6551

Richard

[RRoller123]

Thanks! Will check them out. The cost of a new one puts it way out of consideration. We need to ask them if they REPLACE the TFR board, or just clean it up. That is critical to rebuilding this thing.

[tima01864]

Have you had the AFM serviced? How did it go?

[RRoller123]

I have not. Am thinking of doing it over the Winter, or at least removal, clean the board area, and bend the wiper again to make sure it is riding on fresh TFR.