EGR Overrides and Strategies
Making a secondary EGR came up in another thread.... I happened to have this in a bookmark and would like to open a discussion....
EGR Strategies Quote:
But more, on the subject of hot air intakes -- I remember members saying that at certain high temperatures, their FE actually decreases. This could potentially be the reason why and perhaps worth investigation - EGR output vs. IAT input. Thoughts on this or anything else in the article? |
IAT temp vs FE wall for a saturn S-car seems to be around 200f. I like to see around 170-180 for max FE. I tried a few tanks with the EGR unplugged and didn't really see any difference. The runs were high speed highway. However when cruising below 60mph the scangauge reported gains of 10-20%.
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I've played with the egr solenoid duty cycle map in my ecu in hopes of getting better FE. I get slight misfires at very light throttle opening, which is also when my lean burn code is at it's leanest. My car has port fuel injection. The injectors are about 4" away from the intake valves. I have a standard air intake, and temps stay within 20*F of ambient temps.
There's also the chance that the misfires on my car are due to the extremely small fuel injector duty cycle used at such light throttle, since it takes a certain ammount of time for the injector to open and close, and the duty cycle may be less than the open/close time, which would lead to inaccurate fuel metering. btw, I'm using Denso 660cc injectors, and a big injector needs a smaller duty cycle to supply a given ammount of fuel, plus the bigger injectors take longer to open and close, which makes it worse. When I first felt these light throttle misfires I changed the EGR map to reduce EGR at light throttle in the affected rpm range, and it seemed to help. I still get misfires at very light throttle, but it's just a reminder I'd be better off coasting a little than trying to Drive With Load at such an inefficient load. |
Might try making these plugs?
https://www.brightgreen.us/spark.htm commercial version: https://www.supersonicspark.com/ If you are leaning things out...you need plugs that can better fire a lean mix? |
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