In this day and age of wide band, dyno jets and computer tunning is reading plugs the old fashion way doomed? (and yes I am old) Im just curious as to some feelings on this, I am from the old school before wide bands etc and we tunned our car by reading the spark plugs after a pass, not looking at the datalog and the W/B reading. I have many secrets on the art of plug reading and curious if passing this knowledge on to my kids down the road will fall on def ears. You know youngters now a days. But if enough people show intrest I may share some secrets on it.


Steve

 

im always down to learn something new..

 

i used to read plugs all th etime when i have my mustang. but now, well run the dyno for a while with the wideband, then usually take them out for a quick look over. its still not dead, just dormant

 

i still read my plugs. dont really see the need to do anything else.

 

I read plugs, i learned to when i was 13... about 9 years ago. my dad taught me. I read the plugs on my TA, both my blazers, the Wagon... whatever car i worked on. .

Its kind of a lost art, its mostly just in remission these days w/ the big preponderance of WB02 sensors and datalogging. I mean, its alright if you went WOT and shut-er down after the run, then you could actually see how the tune of your fuel system was during WOT... the problem that comes in is when you start idling and part throttling in addition to WOT. Cuz your Idle air control could be in a different state of tune than your part throttle/cruising/primary circuit and in a completely different state of tune than your WOT/main circuit... so you want to try to tune 3 things by one reading: its not gonna happen. Thats what is beautiful about WB02 and dyno tuning. you can see exaclty how your fuel ratio is during idling, cruising and WOT, and not have to pull your plugs out...

Reading plugs is only going to show you the most predominant trait or most extreme case of tune and override all other readings. If you are rich at WOT and lean at idle and part throttle... you wont know, cuz your plugs will still be black. If you are rich at Idle and part throttle but lean at WOT... youll never know cuz your plugs will still be somewhat black after idling and putting around after a run.. unless you can pull over to the side of the road and inspect your plugs. now, extreme cases such as EXTREMELY high EGT's/Super Leanness will show up as the specs of melted piston, and will still be visable no matter how rich. same w/ excessive errosion of the electrodes.

If i had to choose, id take the Wideband readings in realtime over plug reading. but in a day-to-day life where your average joe doesnt have access to a WB02 or dyno... Plug reading is a must-know talent... some of the youngsters today would be better off knowing how to read a plug (i know im young... but i already know how )

thats all

 

I had a vague notion of plug-reading from doing it with my goped's single spark plug . I'd tune the carb to what I thought was a good setting, take it for a hard run and check the plug, hope to see a nice brown electrode, not white and lean or black and fouled from running rich. When I pulled my plugs to change them on the dsm, they were white, which seemed consistant with having a failing fuel pump that was probably delivering less fuel than it should have. I just checked them when I pulled them to do a compression test, and they were slightly fouled but not white and lean, although I had been running the car in "slow mode" to avoid breaking various stuff except for a few bursts of speed. I believe that the wally with no aftermarket fpr should have me running rich enough not to worry about leaning out, especially with my limited mods and fairly low (16 psi) boost.

 

Man... who you callin old?

yea, it can tell you alot, but "alot" is a subjective term.. it doesnt tell you the whole story or tell you right as it happens. but a WB02 or EGT wont show you specs of melted piston... but, if youve already melted a piston... well, i dont know what to tell you then. you were doing something wrong in the first place and have no business messing w/ cars

seriously though, im just wary of people who try to tune for top end performance on a daily driver... cuz the time spent at part throttle or idling can skew your readings... I remember pulling all the plugs out of the talon when i put in the coppers, and they were all a nice gold-brown color... needless to say, i was very happy to see this and added to my ego of how good i had it tuned. My supra plugs were just as fine. but, i think they are gonna be black now, after my 550's and Lexus meter conversion. I need to hook up my Emanage and reserve some time on a dyno.