I am looking for someone who "UNDERSTANDS" the fuel sync concept in Chrysler efi. Why? I am calling BS on virtually everything I read on the net about how the fuel sync "precisely" establishes when the injectors fire in relationship to intake valve opening. If that was so, the factory spec of +/- 8degrees would be in relationship to the stock camshaft opening point. Since there are three different v8 cams used from 93-98, it seems the sync would be at a specific number of degrees based on which specific cam was installed. All Chrysler says is "...These distributors are equipped with an internal camshaft position (fuel sync) sensor. This sensor provides fuel injection synchronization and cylinder identification ..." Nowhere can I find that the amount of sync degrees correlates with the amount of degrees related to intake valve opening. Additionally, any aftermarket cam or a different rocker ratio would alter the intake opening point. Add 20-30 degrees of duration to the cam and the intake opening is significantly earlier. I don't see any discussion of increasing fuel sync an amount equally proportional with the additional intake opening. In actual practice, +4 to +6 degrees seems to be the normal setting, regardless of camshaft. Consequently, I am not buying sync is based on valve opening but rather, something else. Could someone explain to me what fuel sync establishes? I have found posted by bigpaul "...Fuel sync is the overall injection start point delay measured in internal units." I don't really understand "start point," in relationship to what? I could accept the notion that the sync is tied to piston TDC but not valve opening. I would really like to understand this. Regards, dan...
Red Flag Submitted
Thank you for helping keep Eng-Tips Forums free from inappropriate posts. The Eng-Tips staff will check this out and take appropriate action.
Reply To This Thread
Posting in the Eng-Tips forums is a member-only feature.