Two Problems:On/Off Throttle bucking and Ignition related
Posted: Thu Sep 03, 2009 3:47 pm
I have two problems.
1. I'm experiecing a lot of bucking when I get on and off the throttle. It feels like as soon as I let off or get on the gas, the car bucks a bit. It's almost as if the engine can't decide if should be on the gas or off the gas.
What is the cause of the bucking?
My datalog shows that when I get off the gas, the Tpedal and Tplate hit zero, but the AFR gets rich at the same time for a bit before it leans out. Then when I get back on the gas, the AFR is lean for a bit before it corrects itself back to the 13s area. The graphs look like the AFR is lagging behind.
2. I had to reduce a lot of the timing from the ignition tables to get rid of knock. My tables are no longer smooth. When viewing from 3D, it no longer looks like a smooth hill. There are a few dips at the bottom in the lower RPM range near rows 6,7,8,9.
Should I reduce some of the ignition timing near the dips to smooth out the tables?
3. I might as well throw in a third question while I'm at it. When using the Lambda overlay to see what adjustments should be made, should I be making every single adjustment listed or should I just be removing fuel from the intersection point of RPMs and Rows at a certain cam angle, just like tuning the ignition?
Thanks in advance.
1. I'm experiecing a lot of bucking when I get on and off the throttle. It feels like as soon as I let off or get on the gas, the car bucks a bit. It's almost as if the engine can't decide if should be on the gas or off the gas.
What is the cause of the bucking?
My datalog shows that when I get off the gas, the Tpedal and Tplate hit zero, but the AFR gets rich at the same time for a bit before it leans out. Then when I get back on the gas, the AFR is lean for a bit before it corrects itself back to the 13s area. The graphs look like the AFR is lagging behind.
2. I had to reduce a lot of the timing from the ignition tables to get rid of knock. My tables are no longer smooth. When viewing from 3D, it no longer looks like a smooth hill. There are a few dips at the bottom in the lower RPM range near rows 6,7,8,9.
Should I reduce some of the ignition timing near the dips to smooth out the tables?
3. I might as well throw in a third question while I'm at it. When using the Lambda overlay to see what adjustments should be made, should I be making every single adjustment listed or should I just be removing fuel from the intersection point of RPMs and Rows at a certain cam angle, just like tuning the ignition?
Thanks in advance.