[Mac D]

I know that recommended spark plugs were mentioned in a recent post but I can't find it. So, again, what plugs do you guys recommend for my 91L? She currently sports a set of AC Delco R42XLS plugs, installed by the Alfa mechanic who refurbished the heads about 25K ago. One of these is fouled, resulting in an uneven idle (a simple cleaning gave me back a smooth idle -- which lasted about 2 miles). In times past I used NGK plugs but I've forgotten which ones. I recently noted that Steve recommends Champions (the post I can't find) and there too I don't remember which ones.

Of course, I need to figure out why that particular plug fouled and not the others. Maybe a bad spark plug wire (the wires are original and there's 115,000 miles on the clock)? Perhaps a faulty connection at the injector, or a dirty injector?

I appreciate your two cents worth and favorite plug recommendations.

Mac D

 

[Gubi]

Was it fouled with oil or carbon?

I've always gotten good results with standard NGKs on a variety of cars, but I really like the NGK Iridium plugs. A bit more expensive, but they seem to be very resistant to fouling. My TR7 was running quite rich for a while and I never had trouble getting a good spark out of them.

In any case, you should probably figure out why that one cylinder is problematic.

 

[Alfisto Steve]

Go cheap use Copper Plus 415 Champions set at 0.025" once you figure out why plug fouling. These are one heat range hotter so good for a little oil burning.

 

[Simeon Trendafi]

I had a fouling problem on cylinder #4 from a bad spark plug wire. Check that the wire resistance is within specks, at least that is easy.

Simeon
1991 164S getting close to 100K

 

[donliznev]

Champion 415's are your best bet.

If a plug is fouling (misfiring) then go to basics like distributor cap (cracked) rotor (worn), plug cables (old) or coil (old).......

Fuel injectors are your absolute last resort as these are very reliable.
Fuel injectors connectors are very fragile by now (20 years) so handle with extreme care as they literally crumble when the clips are prized open.
The connectors can be a cause of misfire or no fire and these are difficult to properly clean in place.

If all else fails then dare to touch the injector connectors....

Ta,

Neville.

 

[ChazzyD]

Champion 415s have been awesome in my old girl. They give me a nice smooth idle and nice power. They have been just as good as fancy (and expensive) Golden Lodge plugs I have also run. Dirty cheap and found nearly anywhere.
Charles

 

[Mac D]

Champions

As per the majority decision, I installed a set of Champion 415's. Now she's running much smoother at idle (although there is a slight "hunt" at times) and she's much peppier taking off.

BTW, what is the resistance spec for the plug wires and how is it best measured? I don't have an ohmmeter; I'd have to buy one. Or is it simpler to assume that after 115,000 miles the plug wires are nearing the end of the line and I should just get new ones?

Mac D

 

[Alfisto Steve]

As per the majority decision, I installed a set of Champion 415's. Now she's running much smoother at idle (although there is a slight "hunt" at times) and she's much peppier taking off.

BTW, what is the resistance spec for the plug wires and how is it best measured? I don't have an ohmmeter; I'd have to buy one. Or is it simpler to assume that after 115,000 miles the plug wires are nearing the end of the line and I should just get new ones?

Mac D

2.5kohm per wire and 1kohm for coil wire and 1.1k for dizzy rotor