I'm just about done with my turbo install, but I'm not going to be able to get it tuned for a little while. I hear it's possible to do some high level tuning by checking spark plugs after a run? Could someone please describe how to do this? I understand that white is lean and black is rich. But I'm wondering, how far do you drive before you check them and do you do this at WOT? Any tips would be great....thanks.

 

I've never heard of anyone doing this before. Yes its true, you can get a good indication of how rich/lean you are running due to your plugs but to run your car, check them, install them, run it again and make adjustments and check them again is just rediculous.

 

Here you go asianspeed
The link below has everything you need and will ever need to know about spark plugs, also it will tell you what spark plug heat range to choose!

http://www.centuryperformance.com/spark.htm

 

FYI, the best way to tell how your plugs are is to run the car as hard as you can and shut it off immediately....it's the way to tell if you're running lean at full throttle....since you'll be a lil rich at idle, the carbon may cover the white spots which usually indicates leaness..when you left it at idle before you shut the car off

stan

 

Link doesn't work...

 

Works here.

 

stan hit it right on point thats the only way to really get a good indication

 

 

Well, this is NOT the most accurate method but it should get you started if you don't have other means to monitor your tuning.

1. Hook up a digital multimeter positive lead to the ECU O2 sensor wire.
2. Hook up the negative lead to a good ground.
3. Set the multimeter to low DC voltaqe range.
4. Bring the car to operating temp.
5. Position the multimeter so you can see it while driving.
6. Bring the car to WOT and monitor the voltage reading.
7. Try to adjust your fuel to obtain somewhere between 0.90 to 0.94v during WOT. That should give you approx. 12:1 to 12.5:1. The higher the voltage, the richer the A/F mixture. Btw, idle is usually around 0.74v. The reading will bounce back and forth a lot in idle.
8. Also combine the spark plug reading method to get you safe enough to DRIVE, not RACE to your tuner for the actual tuning.

 

Hey JT, that sounds like something that I can do. Thanks. However, I was wondering, will I get correct readings if I'm using a maplimiter? This won't affect the readings that I get from the mulimeter will it? Oh and where is the ECU O2 sensor wire? Again, thanks JT...this is was just the type of HT information that I was looking for.

 

that's a good use of the digital multimeter !!
cool !! it's probably going to be better than my autometer *jumping* a/f ratio gauge !!

 

The map limiter shouldn't affect it, as you are connecting directly to the O2 wire. The O2 wire is usually a fat white wire. You might be able to find some info here that match your vehicle. http://www.jdmfan.com/index.php?mode=information .