Re: Converting EFI to Carb 4.3 Mercruiser
What is the problem with the old system?? There a little eaiser to repair than you might think.
The problem is that there is an option set for "load anticipation mode" According to the mechanic he believes this is leaving the engine at base time mode all the time. He is claiming that at any throttle position, the timing will not advance. It sounds to me that the signal is expecting a ground to work properly. If I am missing something from a previous post my apoligies, but I don't see anything from old wiring that would change this setting if it truly is the problem. Don by all means jump in there and and explain.
Thanks
MIE Inboards Only
Load Anticipation Mode:
The Load Anticipation mode is on MIE inboard and ski engines only. The function is used to help inboard engines during shifting. An electrical signal from the neutral safety switch (on the transmission) goes to the ECM on J2-20. This signal tells the ECM if the switch is closed or open. In neutral gear, the neutral safety switch is closed (signal grounded). When shifting into gear, the switch opens (signal open). When the transmission is shifted into gear, the open signal causes the ECM to add a calibrated amount of bypass air with the IAC. This is done to increase the load handling capability
of the engine when going into gear on larger boats. When shifting back into neutral gear, the additional IAC bypass air is removed in an attempt to limit engine rpm flares. The amount of IAC air used is constantly monitored by the ECM. After the transmission is shifted, and the engine has stabilized, the ECM calculates an ?error band? from the Moving Desired RPM mode and adjusts the Load Anticipation mode IAC count accordingly. This allows the ECM to ?learn? the best IAC bypass air position to use for shifting each particular boat. NOTE: The Load Anticipation mode is on MIE 454/502 cid inboard engines also.