This advice from HS can save alot of time. I was too focused on each cell when I started tuning, vac/rpm/bpw/afr, Bob showed me exactly what HS described which is to use the graphs to make smooth changes to multiple cells. Other than that, there were a few initial hours in the boat using the laptop to make changes. Once I got the hang of it, as Arctic has said, to make changes in the garage or to have multiple test tunes ready was much easier.
Starting with a tune that is close shouldn't be a problem. Bob will council you not to touch 90% of the tables.

I'm coming in way late here, but just ran across it. To address your questions:

1. While an O2 sensor must be present during tuning, you can remove it once you are happy with the tune and turn off the AutoTune feature. It will then run in open loop with the adjusted tune you created.

2. If the O2 sensor fails, the AutoTune will stop running and adjusting, but any trims already created will still be active.

If you are considering the possibility of running a CMD Marine unit in the future, you may consider our Wideband2 device to monitor you air/fuel ratios. The Wideband2 device has 4 gauge options which will show you your air/fuel ratios, or you can connect our LCD-200 touchscreen device that has logging capability. With the LCD-200 and a 1gb SD card, you can record up to 186 hours of data from the wideband device. The Wideband2 also has a digital input for seeing RPM and an analog input for one 0-5v signal (I'd suggest MAP, as that is likely what you will tune by later). This gives you the ability to log air/fuel ratio with RPM and MAP pressure for graphing ease.

If you decide to add the CMD Marine unit later, just connect the Wideband2 to the CMD Marine unit using a CAN to CAN connection cable (#76950145) and then you can enable the AutoTune feature with the hardware you already have.

Just a note here, in the MAP vs RPM table in the CMD Marine unit, the pressure value break points are user defined and allowed up to 51 break points (every 0.1v from 0 to 5v if you so choose).

Some days later, im on the same point to order mefiburn. Something new in this projekt ?

I haven't been on this site for quite some time, curious why all the misinformation. The mefi 3 and 4 can be programmed real-time without stopping and shutting down the engine. The mefi 4 can run closed loop wide band. I had pondered a couple of years ago to write a strategy for internal self-tune but I really don't need it and got bored with the concept. Mefi1,2 require a shutdown for a few seconds then takes a few seconds to download changes.

Neither have much resolution but will still work in plenty of applications. Mefi1 can't do boost, mefi2 can do boost although just as archaic as mefi3 as just a multiplier based on boost xy and not rpm/kpa xyz like a mefi4. Sheesh, never understood the bashing of mefi computers. The mefi1 first showed in boats in 93 but is almost identical strategy code wise to an 87 chev truck computer with the addition of EEPROM. The mefi4 can do almost anything the aftermarket would want. I've done 1500hp blown marine with it years and years ago. It can run 8 coils, just about any crank/cam trigger you want including a std gm distributor. I generally use it with 60-2 crank and 4x cam and dual knock sensors so the ecu can retard ONLY the cylinder that is knocking. The only real downfall of the mefi4 is it doesn't have the capacity to do sequential fuel. The mefi5,6 does.

It seems alot of people don't know the huge power a mefi controller has. example mefi4b, 8 coil drivers/sequential spark, boost tables to 200kpa(~15lbs) adjustable to 9000rpm fuel and spark, dual fuel available, accurate and complete knock control programmable to allow at what point you want to enrich to aid in controlling runaway detonation. Fuel pressure monitoring to enrich in case you are starting to clog a fuel filter or lose a pump and programmable limp mode so you can look at datalog or gauges to see. Oil pressure vs rpm safety similar to fuel pressure settings. EGT, etc etc.

Anyway, sorry to bore y'all.

I'll ask this again. Anyone near Milwaukee have experience with this program?

I'm getting ready for my winter project. I plan on ordering the MefiBurn software. My ? is about the O2 bings. I contacted CMI about welding the bings in the tails. Do I need bings in all 4 tails? Do I need just 1 O2 setup and after I tune 1 engine put O2 in other engine? I plan on using live and then closed.

I would do 1 per engine, trick is to get them to live...much talk about that...we killed 3 in 2 hours run time...just the exhaust system/cam combo and revision...get it tuned then remove them...

any news? you give up or have a success story to tell?

4bus....any updates on your experience with Mefiburn?

Yes.

I have now the the MefiBurn Software and Hardware.

Very Cool and simpel to work with it.

MefiBurn load the Files from the ECM to the PC. 10sec.
TunerPro modify the Files.
MefiBurn load the Files from PC to the ECM. 10sec.

ScanPro are like Diacom not for twin, but the display for singel are bigger and nicer.


I have used it on my twin 502EFI from 1993.

I modifyed only the Spark and the Fule Tabel upper end.
I have no Dyno in Germany, so i modifyed only the tabel over 4600 RPM. The rest of the fuel tabel are stock.
And i reduced all the lower RPM high spark advance 40+ to only 35*.
The total Spark are now higher than stock.

Boat runs 9kmh faster now.

Im happy with this small changes in the software, and the big changes in speed.


This are my best performance upgrade for the $.