E78 standalone in L96 Jet Boat

[andrew_robertson]

Hi all, have a stock 2015 Marine Power L96 6.0L controlled by a E78 ecm running MEFI 6 in a jet boat (E78 service number 12642442 1138). Being MEFI with wet exhaust it is open loop speed density but does have factory DBW throttle body. Runs fine but I want to do a cam upgrade and tune it. I don't know any cost effective way of editing MEFI 6, so I am thinking of getting another E78 flashed with the stock L96 truck tune, editing that to run SD OL on the bench, and swapping that in so I can use my HPT to tune the boat after I upgrade.

My questions are:

1. Can the standard truck tune E78 be edited to run properly in speed density and open loop without any limp mode and also without any TCM. The boat has no check engine light and only a tach so I don't care if I get fault codes as long as they don't interfere with engine operation and the tach output, oil pressure, water temp signals work.

2. My existing 3 harness connectors will plug right in but is it safe to assume that all the pins do the same thing - is the pinout generic to the E78 or does it change with the OS/Tune? It'd be great to just plug it in and go.

Thanks for your help.

Cheers, Andrew

[GHuggins]

Why can't you just get an ecm for a manual trans car? People have done this before even for plane engines. Just make sure to find one with a 2bar OS option so you're less likely to have SD issues.

[andrew_robertson]

Thanks Greg, was there a manual trans Gen IV 6.0 with VVT and DBW controlled by the E78? If so I agree that would be ideal as a base. I'm also not sure about how to tell if it would have a 2bar OS option - do you know how I could find out? Thanks, Andrew

[Alvin]

Usually MEFI stuff is proprietary and HPtuners will not be able to edit. There are companies that make MEFI tuning software. For instance the GMPP cars use a E67 but it's different than a normal E67 and cannot be used with HPtuners.

Using a GEN 5 torque based controller on something like this will likely be a nightmare. I'd consider using a holley or something.

[GHuggins]

The E78 was used in vehicles that weren't solely torque based too. They were used in Freightliners with 6ls and Alison's not to mention 11 and 12 2500 and 3500 chassi's trucks with 6l's that were still offered with manuals. Problem is other than the freightliners, you're probably going to have problems finding a stock calibration for them.

I was just stating is why tie yourself "just to that". If you want a factory ecm to tune look into manual cars that used something like the e38 or e67 and swap the harness and ecm both. At that point you just need something that can control variable valve timing. OR do like Alvin pointed out and go the Holley Terminator route. Still requires tuning, but if you've set it up right, it'll run fairly decently... I've got a lot of retromods and rock crawlers out there running those systems along with the OE controllers. Personally I think the OE is better and more "fully" tune-able where you're limited by the AM's just because of how they reference timing off of vacuum instead of cylinder airmass. However the AM ones will constantly control and adjust your AFR, which is nice if something starts going sideways... I also don't know of an AM controller that controls VVT. All up to you.

[Alvin]

not to mention 11 and 12 2500 and 3500 chassi's trucks with 6l's that were still offered with manuals.

Those are very much torque based too.


boats can be a real pain in the ass.. especially with the wet exhaust.