Would you buy diagnostic software or calibration software for the Merc MEFI computer

If you want to change the program you better know what you are doing. It ain't easy and it is very time consuming to program an EFIECM.

Trust me I have done many-many (non-marine) and they're easy to screw up if you're new to it.

Roby

I too have done different kinds of ecms (DFI gen 6 and 7, FAST, MEFI, Motec) and know what you say about messing them up. To program a whole computer has just to many variables, so I would limit the variables that could be changed to just a fraction of them i.e.,main fuel table, main spark table, main fuel table multiplier

The key would be cost. If it's affordable I would definitely do it.

My vote for this poll is that "Allan4 is still a putz"

I bought the RINDA Tester and it's been worth the money even thought it doesn't allow reprogramming it lets you see all the EFI data available and lets you validate what the gauges say and what the symptoms seem to say.

A great project would be to grab all the data at the ECM and use to to drive a simple, vcost effective electronic dash and/or log all the data for a run. It's the principle used in smartcraft instruments but those damkned things are way over priced for now.

The diagnostic and calibration software may have the ability to display certain parameters similar to the current DFI systems. It could also log the operating parameters for a run and later be displayed on the dash board. What tables would be most usefull? The current MEFI system has over 100 tables that could be modified.

OK, So what do you have?

Are you speaking of the DFI systems as were used years ago on cars for racing? Today there are many new systems out that have a much broader scope of parameters and easier tuning capability. AEM makes one of the most user friendly systems that I have ever seen. My 1994 Ford Lightning makes over 1072 rwhp and still pulls 18mpg when cruising on the freeway with the AC on. These new systems are far better than the old school thought that has been handed down to the marine industry.

Getting a hold of the fuel management systems on Marine engines will net great gains in both performance and economy. If someone offers a decent upgrade to tune the factory ecu, I would entertain purchasing such.

Phughes, So what do you have. I want to replace the ECU on my 500 EFI. What can you suggest/do?