Haydo Posted January 19, 2021 Share Posted January 19, 2021 wonder if i could have some input on this, cars been tuned and is all good trough the rev range except light throttle where it pegs 22:1 afr. car has vernier gears and camshafts ill attach two data logs from this morning lean 4th gear full throttle low rpm.teclog lean light throttle.teclog Quote Link to comment Share on other sites More sharing options...
Roland@pcmtec Posted January 19, 2021 Share Posted January 19, 2021 What are the camshaft specs? You have a huge camshaft error indicating the camshaft + valve springs are too much for the actuator oil pressure to overcome and VCT system is failing. Has the VCT system been locked out correctly? The actual measured cam angle itself is still moving according to the logs. The log doesn't have any wideband data so it is not possible to see where it is going lean. I would suspect it is due to the the speed density not being properly recalibrated for the different camshafts. Tuning camshafts is very time consuming to get right, if you have VCT it becomes much more difficult to get right. You need to recalibrate both the speed density map slope and speed density map offset tables to get the fueling right. Quote Link to comment Share on other sites More sharing options...
Roland@pcmtec Posted January 19, 2021 Share Posted January 19, 2021 Have a read of this guide as well https://forum.pcmtec.com/topic/239-howto-tuning-cams/ Quote Link to comment Share on other sites More sharing options...
Haydo Posted January 19, 2021 Author Share Posted January 19, 2021 cam shafts are dialled in with verniers and running vct solenoid deletes, the cam angle error would be the camshafts stuck in a different positon to what the orignal tune is allowing i would assume ? Quote Link to comment Share on other sites More sharing options...
Roland@pcmtec Posted January 19, 2021 Share Posted January 19, 2021 33 minutes ago, Haydo said: cam shafts are dialled in with verniers and running vct solenoid deletes, the cam angle error would be the camshafts stuck in a different positon to what the orignal tune is allowing i would assume ? What is strange is the actual camshaft position itself seems to be moving in the log. It is possible that when the VCT is disabled it simply mirrors the commanded cam position which would make more sense. If the cam is properly locked then I would make sure the VCT is disabled in software in your tune, then follow the "Locked VCT" part of the procedure in the guide above. Locked VCT is MUCH easier to tune if you use our Custom OS feature so you can hopefully get the tune sorted out fairly quickly. Quote Link to comment Share on other sites More sharing options...
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