Noticed tpenfield didn't respond, he has the Diacom software.

Do agree nothing is ever easy. Did Bob say anything about the current issue?

Yes, said to swap the ECU's from side to side which I did August 20th and netted the same issue. Doesn't matter as the issue lies in the synchronization via the wiring creating a master/slave not that one is programmed master and the other slave. I requested the lengthy instructions he said exists to connect to the slave through the master like (apparently) Rinda allows on 9/24/18 via email. We'll see what that nets. If zilch I guess I'm buying someone else's software etc. and eating $200 on OBD's.

Keith

UPDATE

The only way to see one or the other with OBD's ScannerPro is with an coding change to the program itself each time you want to flip back and forth. In speaking with Rinda about the Diacom software they noted if both ECU's are internally programmed as slaves their software will do the same thing. I therefore, chose was to send both ECU's to MEFI Burn to have the master/slave architecture to be removed altogether. Currently waiting on the ECU's to be returned to me.

About a half hour after typing the above I found the below picture in my archive!!

Looks like the port side ECU master/slave connection wire. I probably tucked it away after taking the picture over a year ago and is why I didn't find upon my initial inspection. This may be the issue all along but will need to find out why its disconnected, what pin the red wire goes to and why, where the red wire connects on the other end and why. Fun times! Stand by...............

https://uniim1.shutterfly.com/ng/ser...537344/enhance


Keith

UPDATE

The issue of the thread is now solved and I can finally scan to find the original off idle surge problem.

MEFI Burn disabled the synchronization link between the ECU's but I still had to unplug each (engine) single yellow wire connector to 3 wire connector.

I confirmed data stream into the logger per engine when hooked to each engine DLC and each engine ignition on separately.

BUP,
Now I'd like to know why Merc would sync the engines via the harness.

Keith

MerCruiser lists their reason in the service manual as keeping the boat from going into a hard turn if one engine goes to idle while the other one is at full throttle. Not sure about the other reasons.

With Volvo, it will also sync the water temp and oil pressure gauges when they are close to each other as well as providing engine RPM sync when both engines are close. But this is just on the newer engines. MEFI isn't smart enough to do that.