Wierd tuning issue with Whipple engine - Holley ecu
05-14-2015, 05:42 PM
#31
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Location: Spicewood, Texas USA
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Once we turned off closed loop you could really see what was going on. The pulse width is not increasing in proportion to it going rich, so to me that takes the ecu tuning out of the picture. The engine has a significant stumble when the A/F readings are showing rich, so I tend to believe the reading is reasonably accurate. I was able to "tune" the problem out by leaning out the 1-2 cells in the map where it was happening. I made it as lean as possible at that point so it would accelerate through it when everything was normal, but when it loads with fuel it's not so rich that it stumbles. Hope this makes sense...clear as mud..LOL.
Are you reading the A/F on the dashboard, when this is occurring? If this is happening change your parameters for closed-loop learn. You can also look at you coolant temperature enrichment parameters, the engine may also be dropping below your set, parameter after idling. Haxby, is going to be the EXPERT on this. I have only been using the Holley for a year at this point. I know, for a fact the smallest amount of moisture, hitting the wide band will send it to a dead rich condition !!!!! Its more prone to happen, if there is a full swim platform at water level, until the boat is on plane.
05-15-2015, 04:18 PM
#32
You have to keep in mind that a wideband will not show a rich condition if there is a big excess of fuel. The O2 sensor has no way to read liquid fuel, or any form of fuel for that matter. Actually, an overly rich condition can show up as the engine being lean on a wideband. Once that overly rich mixture starts to take out the plugs, they can not effectively burn off all of the oxygen. Now, you end up with a surplus of unburned oxygen in the exhaust pipes. The O2 sensors interprets that as a lean condition, when in fact, the engine is rich.
Eddie
Eddie
05-15-2015, 06:58 PM
#33
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That has not been my experience. I've poured fuel into motors to the point where I'm nearly bottoming out the wide-band reading (close to 9.x) and it never indicated lean. My eye's were watering from the exhaust it was so rich. Not saying it can't happen but that is not the case here. Wideband reading coupled with BPW is going to tell you to a high degree of accuracy what's going on.
Eddie
