I guess my questions then would be: 1) why then is it thought that the '94 ECU is a richer mix than the '93 ECU which is why the '93 gets better gas mileage but does the cold weather stall if the throttle is abruptly shut when the engine's cold?
If the TPS controlled just the mixture wouldn't adjustment of the TPS have cured this condition on the '93s or is it too fine of an adjustment to do this? 2) Many have reported that adjusting the TPS seems to move the "surge" up and down in the rpm range as well, that behavior doesn't seem to me like making the mixture rich or lean if the problem still exists just in different rpms. My '93 doesn't really surge that much (mostly only at very low speeds in parking lots or heavy traffic going real slow) and I'm sure not as much as some who've experienced it based on their comments. Also Kevin Hawkins rode mine once and said mine was much smoother than his. When I have time to put on the new brake lines I'll measure my TPS just to see what it's set for. I'll also look at the mixture screws since mine are still in the stock factory settings and never been changed. I would also believe that this would be different on alot of bikes just due to slight manufacturing differences. I think the best approach is get a reading where you are and try it higher and lower to see if it improves or gets worse, if not put it back and leave it well enough alone. -----Original Message----- From: [EMAIL PROTECTED] [ mailto:[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> ] Sent: Wednesday, October 03, 2001 10:03 AM To: [EMAIL PROTECTED] Subject: TPS and FI relationshipRe: "Yes It's Over"---"The Surge is Gone!!!!" The reasoning behind having a TPS in a fuel injection system is to provide the FI information as to how much air is flowing into the engine. Optimal fuel air ratio is 14.7 to 1, so for the FI to be able to provide the correct amount of fuel, it has to "know" about how much air is being ingested. The relative position of the throttle plates allows that estimation to mathematically calculated so proper fuel flow rate can be delivered. By adjusting the TPS, you are in effect tricking the FI to think you are flowing more or less air than what you really are. This is a way that you can richen or lean the mixture slightly. By increasing the TPS position, the FI thinks the throttle is open more than it really is, so it provides a bit more fuel to each cylinder. Conversely, closing the TPS would make it lean out. The surge is a classic lean condition, and therefore is addressed and improved upon by richening the mixture. I have mixed emotions on the effects of the idle mixture screws on the ECU concerning their effectiveness at partial throttle openings. If this were a carbureted bike, they would be contributing. The reason I am mixed on it is these are electronic controls and not mechanical like fuel screws on carbs. Fuel screws on carbs are still exposed to engine vacuum so they keep feeding even if the engine is not idling. A FI system technically does not need this because the fuel curve can be programmed electronically and not determined by the fuel screw, float height, Jet Needle, Needle Jet, Clip position slide cut away or CV slide spring rate/preload or main jet. You get the idea......... Much easier to adjust or create a fuel curve on an FI bike. Anyhow....... hope this clears up some of the confusion, without creating more. RSRBOB
