Robert B. Cope Posted September 10, 2022 Report Share Posted September 10, 2022 Hello, I've got an SC400 w/ 1uz VVTI motor. Previously it had a stock motor and the tune was great. I had a new motor build, with big cam and head work to match, etc, etc. I basically scaled the old tune up a bit and it seems to work okay. But at low RPM, when I floor it, or tip in significantly, I get a lot of popping and banging, then it starts to go. It looks like it goes lean on me: I have tried playing with various accel enrichment settings and cannot get it to go away. Any thoughts or help would be appreciated. Thank you! SC400-NEW-MOTOR-4.pclr 5.llg Quote Link to comment Share on other sites More sharing options...
Adamw Posted September 10, 2022 Report Share Posted September 10, 2022 You've got way too much accel enrichment I would say, you have ~100% extra fuel being dumped in for only the smallest throttle movement. Drop your accel sensitivity down to about 30, and halve the current values in your clamp table would put you back somewhere closer to what I expect to see. Quote Link to comment Share on other sites More sharing options...
Robert B. Cope Posted September 10, 2022 Author Report Share Posted September 10, 2022 Thanks. I will give that a try and report back. Quote Link to comment Share on other sites More sharing options...
Robert B. Cope Posted September 11, 2022 Author Report Share Posted September 11, 2022 Had a moment this morning to test this and it definitely helped. Will have to dial it in, of course, but I see light at the end of the tunnel now. I feel silly not to have seen it myself. Thank you! Quote Link to comment Share on other sites More sharing options...
Adamw Posted September 11, 2022 Report Share Posted September 11, 2022 I suggest adding the parameter "accel fuel" to your time plot so you can see where it is happening and how much it is adding. It wont mean a lot to you initially, but it is helpful to see as you make changes. Obviously you dont want it so sensitive that is is adding extra fuel at every small touch of throttle, but you should see a decent spike during a quick stab. It varies a lot from engine to engine, but just to give you an idea I most commonly see small/short spikes of accel enrichment up to around 35-50% with a fairly quick throttle movement. Quote Link to comment Share on other sites More sharing options...
Robert B. Cope Posted September 11, 2022 Author Report Share Posted September 11, 2022 I actually have it graphed, but to your point, I don't really know what it was supposed to look like. I saw it go lean and thought "okay, I can add a bit more fuel" but that obviously didn't do anything good. I should have thought to try less fuel, even if that didn't seem right. Quote Link to comment Share on other sites More sharing options...
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