Loki Posted July 24, 2019 Share Posted July 24, 2019 Quote Link to comment Share on other sites More sharing options...
Roland@pcmtec Posted July 25, 2019 Share Posted July 25, 2019 It multiplies the calculated airmass. If the airmass increases then it will inject more fuel. It makes sense as well as colder air is denser, hence more airmass for a given pressure/volume. You can read about the ideal gas law here to confirm. https://www.quora.com/How-temperature-is-related-to-density So knowing that you would increase the number to richen, decrease to lean it out. Quote Link to comment Share on other sites More sharing options...
Loki Posted July 25, 2019 Author Share Posted July 25, 2019 Thank you so much. Now I have this stupid issue when air intake temp changes! When air intake temp increases, the fuel trim will increase in positive at Park in Gear.. say 4-5% - not Park in Neutral. However the cruising fuel trim still spots on!!! Then intake air temp decreases, the fuel trim at Park in Gear (when you stop at traffic light and such) the fuel trim will move towards zero again. No affect on cruise fuel trim though. As air intake temp increases, the idle will be more rough and load increases as well in Park in Gear - REV will vary between 550-580RPM As air intake temp decrease, the idle will be a lot smoother and load will decrease while REV will be close to 550RPM as set up I am really annoyed about the condition of the tune changing with Air intake TEMP, must be some Air temp compensation vs Fuel!!! Quote Link to comment Share on other sites More sharing options...
Roland@pcmtec Posted July 25, 2019 Share Posted July 25, 2019 Could possibly be your injectors or fuel pressure. Are you logging cam timing when this occurs? It could be the VCT cleaning process. I would log injector pulse width as well, this will tell you if its occuring due to the PCM or its occuring due to VE changing or the injectors not delivering what they should be. 4% fuel trims with large injectors is pretty good, you likely won't improve it much beyond that. Quote Link to comment Share on other sites More sharing options...
Loki Posted July 25, 2019 Author Share Posted July 25, 2019 8 minutes ago, Roland@pcmtec said: Could possibly be your injectors or fuel pressure. Are you logging cam timing when this occurs? It could be the VCT cleaning process. I would log injector pulse width as well, this will tell you if its occuring due to the PCM or its occuring due to VE changing or the injectors not delivering what they should be. 4% fuel trims with large injectors is pretty good, you likely won't improve it much beyond that. Thanks to your help I got the fuel trim works much better in both low and high Air temp Intake - manipulating the auF0052 table slowly everyday. I will stop chasing the Park in Gear fuel trim then as long as it is less than 5%. 1 Quote Link to comment Share on other sites More sharing options...
Roland@pcmtec Posted July 25, 2019 Share Posted July 25, 2019 If the car drives fine with no stumples, flat spots or hunting and your trims are 5% or lower then I would just call it a day as you will have a car driving better than almost every other aftermarket tuned one out there. 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.