Help me understand why fuel cut is kicking in
2 Attachment(s)
Ok as I drive around and let off the accelerator my AFR will jump to max (22.4%), when I try to tune the VE table the bottom 2 rows wind up being very high. So I decided to turn off overrun fuel cut by lowering the MAP setting in in Engine State Settings to 1 ( it was set to 18). It didn't seem to make a difference, What am I doing wrong?
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My first guess is your dead time is off (.767 is pretty short) and/or you need some small pulse width adjustments.
I don't see any fuel cut showing up in your log. You would normally see PW drop to 0, and your log shows a min PW of 1.21ms. However, you do go full lean whenever you are under PW of about 1.6 ms. I had this issue when my dead time was off and I also needed to adjust small pulse width to handle non-linear fuel delivery at low pulse widths. What injectors are you using? |
I'm using DW 700 injectors. I thought that dead time looked off but I got it from this table. I'll bump it back up and see if that will help. Thanks
https://cimg8.ibsrv.net/gimg/www.mia...54a6ff7e35.jpg |
Your dead time might be ok then.
If you have a 1999+, you should be using the 58 psi table - I think earlier models should use 43.5 table. It looks like your voltage compensation curve isn't set to the table values - update your voltage % Curve 1 table to the numbers shown in the 58 psi table. |
Ok, l increased the injector dead time to 1ms and it didn’t make a difference. It really looks like overrun fuel cut is kicking in I just don’t know why.
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As was already pointed out, it's not fuel cut. PW under about 1.5ms looks to be giving you no fuel. This points to a dead-time issue. You have to input everything from the sheet including the correct curve.
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Thanks guys you were correct I slowly increased the injector dead time and when it got to1.55 ms AFR’s stabilized. Now I need to re-tune the VE table
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I'm not sure you are listening ...
You NEED to configure your injector voltage curve on the Injector Dead-Time dialog before you do anything else! Especially before you re-tune your VE map. Populate Curve 1 with the values from the 58 psi injector data table you showed earlier (if you have a 1999+). See if that works for you; once done then you can play with your dead-time, if still needed. You can get the cell table to show at the bottom by clicking on the right hand 3 dots (...) https://cimg6.ibsrv.net/gimg/www.mia...72630ea446.png |
Originally Posted by VcrMiata
(Post 1550022)
I'm not sure you are listening ...
You NEED to configure your injector voltage curve on the Injector Dead-Time dialog before you do anything else! Especially before you re-tune your VE map. Populate Curve 1 with the values from the 58 psi injector data table you showed earlier (if you have a 1999+). See if that works for you; once done then you can play with your dead-time, if still needed. You can get the cell table to show at the bottom by clicking on the right hand 3 dots (...) https://cimg6.ibsrv.net/gimg/www.mia...72630ea446.png Thanks, I change the curve first and it didn’t help. I left the new curve in place then slowly increase the dead time until I quit going lean. |
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