Are there any GOOD websites that tell how to interpret used spark plugs? All the ones I find either suck or are in Black and White. Whose bright idea is that?
Easy, Black carbon is too rich Black oily is needs rings or rebore time White is too lean Go for a light to medum tan.
yeah, but what if your electrode is WHITE and the top of the threads is BLACK. Mine is telling me, with the white electrode, that it is lean. However, when I get on it and accelerate hard, I get a brown smoke puff out the tail pipe, indicative of RICH. My tail pipe is BLACK and (this is a late model car with A/F meter) the A/F meter says I've got plenty of fuel too. Is it possible that the white just means, "change me, I'm old?"
how about those color pix that are in clymer's? most all of them have those pages, but i've always wanted to know someone's opinion of them. as far as i know i just have to trust them as being accurate 'cause i have no other/better info.
I am wondering about that white/light tan looking spark plug with a BLACK sooty tail pipe as well......?????? I seem to have the same thing going on. WTF. Anyone got any answers. Is a black sooty tailpipe just part of the game..... DOES ANYONE "READ" TAILPIPES??? later, JT.
Thanks Drewfus, mine don't look like any of those, and ALL of mine look the same. I think it might have something to do with the "Overheating" one, that write up sounds like that is a possibility. Before I changed the radiator (no leaks, just bad on the inside, I found out after putting a new one in) the car would run on the hot side. Thanks for the info.
Reading plugs has changed a little since most of us "old schoolers" learned to do it, but the basics remain constant. What I always liked to do was to install a fresh set of plugs and motor on over to the free way. Running the car at a fast cruise, I'd cut the engine and coast into a rest area to pull and read the plugs. A "fat" accelerator pump shot, improper power valve, or wrong float setting will affect your plug reading around town, so this method worked best for me when checking for proper main jet size. Modern "detergent" fuel additives and unleaded gasolines have changed the coloration on plugs slightly, but once you get the knack for reading them, it's easy stuff!!!! Most times a light white is good, but if there are signs of excessive heat, such as burned electrodes, then you are WAY too lean! The puffs of smoke you mentioned could be related to the accelerator pump circuit, or a power valve issue. Always start your basic carb troubleshooting by setting the float level. You'd be surprised at how many times that alone cures a problem! Next, set your ignition timing and your idle mixture. (If you run points, adjust the dwell setting BEFORE you set the timing...dwell affects timing, but timing does not affect dwell!) Get to a "test & tune" night at local drag strip if possible. This will afford you the chance to make full throttle passes and take plug readings. This post could go on nearly to infinitum, but you get the idea!!!
Yeah, Fat Hack, unfortunately this is on my late model fuel injected jobbie, so I'll play around with it. I'm not worried, the plugs were old, and they were a different heat range than what should have been in there. It had been so long since I drove the car I had forgotten. I think the plugs I wanted were not in stock, so I got the different heat range. I got new ones, the proper heat range, and I'm sure it'll be ok.
Oh! Well, hell...I didn't know we were talkin' about an EFI equipped ride! Plug readings can be a little different there, but essentially the same! Your "sometimes rich" condition from an EFI car can likely be traced to an O2 sensor. They get ignored until they cause a problem, but I like to replace them with every third oil change as regular maintenence. Depending what kind of car and engine you have, there could also be an issue with the MAP sensor, EGR circuit, or other areas. O2 sensor would be a good place to start though!!!
Well, I just went to NGK's web site and it seems I had a hotter plug than I should have had in there. That and the cooling problems I was been having recently are probably the answer. The O2 sensor is fairly new.
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