1MZ powered MR2
Join Date: Jun 2010
Location: Victorville, CA
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanked 159 Times in 138 Posts
iTrader Score: 0 reviews
I beg to differ.
Changing heat ranges adds/removes 70-100*C from the combustion chamber for each heat range. 1-step colder will remove 70-100*C, which is equivalent to 10* of ignition retard.
I fail smog with the 1MZ's stock heat range. I pass smog with 1-step hotter plugs. The hotter plugs cut HCs (unburned fuel) roughly in half (108ppm to 53ppm; passing is 54ppm). The CA ECU I have runs richer during the 15mph test because it expects pre-catalysts (don't have them) and uses the fuel to keep them hot.
If the porcelain were WHITE, the plug would be too hot. It looks fine (pink to dark pink is good). The rest of the deposits can be from poor fuel quality.
I hope I still have them. If I don't, just imagine the tip of the ground electrode completely worn down. I had to push the ground electrode inward and down toward the tip to reduce the gap and prevent misfires while I waited for the SK20R11s.
Wasted spark is the type of direct ignition system the 1997-2001 5SFE uses. It pairs cylinders 1-4 and 2-3 on the same coil/igniter assembly (2-wires are attached to each coil/igniter). So when cylinder 1 fires in the power stroke, cylinder 4 also fires (very weakly) in the exhaust stroke. That's the basic premise.
1991 Toyota MR2 V6
Ported, rebuilt MY2000 3.0L 1MZ
Fully OBDII compliant and California smog legal
Last edited by Jason.MZW20; 10-08-2012 at 02:24 AM.