Tuning and Spark Plug Color

gotglasses · #1 (**permalink**) 01-04-2004, 08:59 PM

Does an Alfa Sparkplug ever look like those pretty pictures of a "Normal Plug" with a Tan/ brown insulator and light grey electrodes? I'm now running Golden Lodge plugs.

I've owned 4 Alfas and have boxes of nearly new plugs - all black and carbon fouled. Adjusting the mixture on my 86 Spider via the AFM is effective for emissions , but the plugs still run very dark. I'm afraid to lean it out too much for fear of burning the valves.

Can I safely lean out the mixture, by increasing the spring pressure in the AFM, until I get a nice plug color? Or is the black sooty plug tip the nature of the beast?

Can ignition timing play a role in this?

**Gubi** · #2 (**permalink**) 01-05-2004, 08:03 PM

I just went through this with my mechanic. What he told me in a nutshell is that darker plugs are generally no problem on a fuel injected Alfa. If you've got a ton of carbon on them you may have issues, but even if she's running well they're probably never going to look nice and brown.

I was a little paranoid, as all my previous cars always had lovely brown plugs. Darned Japanese cars - always doing everything right! They've ruined me forever!

If you're really concerned, take it in to someone experienced with Alfa engines and have them take a look at the plugs and the emissions. I think that %CO goes high if it's running rich.

evilgidget · #3 (**permalink**) 01-11-2004, 03:08 AM

Pulled the plugs on mine today and they were that lovely brownish colour that the books say they should be, instead of the usual black & carbonised. Is this a sign that my motor has something horribly wrong and it's going to catastrophicly fail next time i start it (after all, they are SUPPOSED to be black, aren't they)?

On a serious note though, has anyone ever had the exhaust valves (i think) try to take a chunk out of the ground on their plugs?
I noticed one of mine has a nice big wear mark on it now from where it's been rubbing (the valve still looks ok though)

**papajam** · #4 (**permalink**) 01-11-2004, 06:12 AM

Quote:

Originally posted by evilgidget
...has anyone ever had the exhaust valves (i think) try to take a chunk out of the ground on their plugs?

**Gubi** · #5 (**permalink**) 01-11-2004, 06:18 PM

[quote]Originally posted by evilgidget
[b]Pulled the plugs on mine today and they were that lovely brownish colour that the books say they should be, instead of the usual black & carbonised. Is this a sign that my motor has something horribly wrong and it's going to catastrophicly fail next time i start it (after all, they are SUPPOSED to be black, aren't they)?

Well, an '80 GTV is either SPICA or carbs, right? I would assume that there's a lot more flexibility there to adjust things lean/rich. A Bosch system with a working O2 sensor tends to be more self-limiting. In my case the car runs and idles great, the emissions are good across the board, the mileage is fine, and the O2 sensor is good. At 30k, the plugs aren't horribly fouled, per se (no piles of carbon on them, for example) but they are a lot darker than I'm used to...maybe 7ish on the following page.

http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html

If all of the above hold true for gotglasses, I would argue that there's probably not an issue. I just got worried because the ones on my Integra were always damn near perfect. I have since learned to recalibrate my mental trouble-meter (about things like oil leaks, for example

).

Now this would not be the first time I've been wrong, so if everyone else who has a Bosch FI Spider always gets brown plugs you'd better all tell me quick before I melt my converter. The local Alfa guy (who's seen a lot more Spiders than me and who I would assume has a monetary incentive to find problems) did not see an issue with it either, though, which is comforting.

Like I said, if he's really worried about it he should check the %CO numbers and/or show the plugs to someone.

evilgidget · #6 (**permalink**) 01-11-2004, 06:48 PM

Thanks for the thread Jim, my problem *looks* like it was indexed incorrectly, combined with bigger valves & big cam lift (curse them

). Goes to show i should check ALL the forums before i post.

Re: brown plugs, mine is a carb'd motor, and has had no tuning done since the last set of plugs (which fouled quickly & all sets beforehand had been black....). I just figured it's odd that it's suddenly running brown plugs

i'm just being smart

**Sniady** · #7 (**permalink**) 01-11-2004, 09:03 PM

lodges run great the first few days (for me). My alfa is not tuned right. But i recently switched to a NGK hot plug, and man it worked me wonders. I now have a golden brown plug.

gotglasses · #8 (**permalink**) 01-18-2004, 06:55 PM

Thanks Sniady! I'll try that NGK , I have a supply of NGK BPS-6.

Is that the number you used?

gotglasses · #9 (**permalink**) 01-18-2004, 07:10 PM

Thanks Gubi for great link! My pluugs are a 7 here, so I'll try BP-6ES NGK's if they fit.

Good possibility that PO's also progressively richened the mixture at the AFM.

**Gubi** · #10 (**permalink**) 01-18-2004, 08:06 PM

Gotglasses: here's a site that has a pretty comprehensive L-Jetronic tuneup procedure. It's for a GTV6, but some of the stuff may help for your Spider if you really think it's messed up.

http://www.oldebottles.com/italiancarspage3.htm

My Cartalk disk also has diagnostics/testing for the Bosch system (Motronic). Perhaps the earlier Cardisk has L-Jetronic checks? At the very least, I'd confirm the O2 sensor is good before doing anything to the AFM.

Like I said, my plugs are about a 7 too and I've managed to convince myself (after some long chats with my mechanic) that there's nothing wrong with the Bosch system...I probably just get stuck in too much traffic. If it's really running rich, you should see a lot of CO out of the tailpipe due to incomplete combustion.