| Slant Six Forum https://slantsix.org/forum/ |
|
| Idle tuning questions. https://slantsix.org/forum/viewtopic.php?t=53360 |
Page 1 of 1 |
| Author: | Sam Powell [ Tue Sep 17, 2013 7:06 pm ] |
| Post subject: | Idle tuning questions. |
My slant idles nicely when the AF ratio is 12.5:1 or richer, but if I try to make it idle leaner it begins to hunt up and down like a lean surge on about a 2 second cycle. The rpm does not change a lot, and never sounds like it will die, but am wondering if there are ideas about tuning this smoother at a more lean mixture. I have checked the timing, and it is stable. The MAP reading does go up and down. Any ideas about what could be causing this? With the larger injectors it did not idle as smoothly but could be made to idle at 14:1 with a steady RPM. The timing at idle is 12 advanced. It idles around 900 RPM. It has an idle air solenoid, but am not sure it works correctly. It does keep the rpm up higher for about 20 seconds when it first starts. Thanks for any ideas. Sam |
|
| Author: | Sam Powell [ Wed Sep 18, 2013 5:20 am ] |
| Post subject: | |
In thinking over my own question, I wonder if there is a small vacuum leak that is masked by a rich idle mixture? On a more basic level, is 12.5:1 overly rich. What AF ratios are others seeing at idle? Thanks for your thoughts. Sam |
|
| Author: | Matt Cramer [ Wed Sep 18, 2013 7:39 am ] |
| Post subject: | |
That's SLIGHTLY rich, but not crazy rich, for idle with batch fire. Without sequential injection, you can get intake reversion that you need to turn up the fueling a little bit to compensate for. We have some tips on idle tuning here: http://www.diyautotune.com/tech_article ... uning.html |
|
| Author: | Sam Powell [ Wed Sep 18, 2013 11:33 am ] |
| Post subject: | |
Thanks Matt. I will look that up when I get home. Sam |
|
| Page 1 of 1 | All times are UTC-08:00 |
| Powered by phpBB® Forum Software © phpBB Limited https://www.phpbb.com/ |
|