I have not posted much for quite a while. Maybe it's about time, maybe it's too soon.
This really isn't a question. It is passing on an experience that might be useful to others. Mileage changes inferred from this are subtle and seem to coincide with seasonal gas changes so I would not may too much of the mileage variation. Last fall my mileage dropped more than I expected. The engine seemed to have a bit more roughness but had always missed a bit when running over 200 F IAT. This spring it started setting a CEL for cyl #3 miss. It only did this between about 100 and 130 deg. F water temp.
I could not pass the emissions test. They only read the code but while I could go for a few days without setting the light I never went long enough to get a ready state. Also I had forgot that I don't get a ready state with the IAC unplugged. I verified all ignition components but installed a set of spiral wound plug wires even though the old ones ohm-ed out fine. As some who have followed me know I have pushed the limits sometimes. I began to have thoughts of failed piston rings, burned valves, or a damaged camshaft. All those components seemed fine.
As a kid I watched my dad many times moderately rev an engine, cut the ignition, hold the throttle open and listen carefully as the engine coasted to a stop. If a valve or other factor is affecting the engine you can almost always hear it in the intake and exhaust sounds after the ignition is cut. if the engine just has an ignition problem it will smooth out as soon as the ignition is cut. My car passed this kind of test. Yes I know how to do compression and blow down tests. I have done those types of tests in other times but they almost never told me anything that was not obvious by turning the engine or listening too it. Anyway I still had a check engine light.
I pulled the injectors and sent them to Witchhunter Performance.
http://www.witchhunter.com/
#3 injector was down 9% with a bad spray pattern. # 2 injector was down 5% with a poor spray pattern. The injectors came back calibrated within 1%. Cleaning and calibration was $18 per injector and $10 shipping. I am very pleased. Never set the CEL again and passed emissions shortly thereafter.
Also the engine is smoother at high intake temps that it ever was. I think my mileage is a bit better but I would not make too much of it.
The Scangauge has me right at 55 mpg at 65 mph now in the current warm temps. To get that good I need to draft a little bit. A good point I have read recently is that the Scangauge is a darn good tool but just because the overall average is correct it might not be accurate in all situations.
Just putting in an unpaid plug for WitchHunter Performance.
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I was also setting a fuel tank pressure is abnormal code. My voltage was dropping abnormally low. After reinstalling the alternator belt I never set that code again. Maybe it was a factor. I have my engine compartment sealed up pretty well. It turns out that a fairly new battery had a failed cell. This failure went on quite a while longer than it might have because even though the voltage dropped to near 9 volts the battery kept a respectable amperage output. The engine always started but cranked slow. Admittedly I may have damaged the battery by high under hood temps. If this battery fails early it probably is not a coincidence. Just fessing up a bit. This is certainly a known risk with the temps I am running under the hood.
Battery relocation may be required. That would make a nice area for a compact HHO generator. Just dreaming. If it gave me a 20% improvement by golly that would be acceptable mileage.
I do have a Smack copy nearly done. Still debating about frequency and magnetic coupling rather than finishing and installing.
Ernie
Linear Mode
