Any Volvo Penta whizzbang ECM experts in here ???
 

I'm trying to make some minor cheap upgrades to my 2007 Chap 256ssx.

It currently has ECM# 3885461, which is correct for the 380hp 8.1, Gi-H package.

I managed to find a complete wiring harness and ECM from a VP 8.1 GXi which is supposed to be a 420hp combo and compatible with Raylar kits. This ECM is number 3883664 and I *believe* is from 2005.
I also have a few new 420hp HO camshafts under my workbench... so that is a cheap option as well.


I'm curious what issues I may encounter and if this 3883664 ECM will plug into my existing 2007 harness, or if I will need to swap the entire mess. I dont know what years the 3883664 ECM was used and if it's compatible with my 2007 drive by wire throttle. I have no problem swapping to a cable throttle if thats the only issue... but it would be eff'n wonderful if it would just plug and play.

I spent $500 for this used harness and ECM so I dont want to just jam connectors together and brick the ECM.

Thanks in advance !

Reach out to John Mosetti (BUP) at Boats Unlimited - he's in the Houston area. He's really good with the factory ECM thing. Not sure about Volvo specific, but I know that he is able to repair the GM ECM at the board level. Worth a shot.
https://www.boatunlimited.com/

What exactly are you trying to achieve??

Sounds like he's turning a 8.1 GI into a 8.1 GXi with a cam and ECM change.

Be warned that GXi ECM tune is one of the worst running and bad behavior inducing software programs ever. I don't know what they were thinking when they programed it. During the time they were for sale, the dealer I worked with actually wouldn't order the GXi's because they were just awful and the Gi's were fine.

Another reason the Merc 496's were better IMHO. Smooth......

Where you been Griff? :drink: :party-smiley-004:

https://www.offshoreonly.com/forums/...ing-alone.html

https://www.offshoreonly.com/forums/...ter-550ci.html

Mo powa

Whats Larrys take on this? I know Ray wasnt big on them at all... I know its money, but its money well spent. In a HP application, like what you are going after I dont know if its worth messing with the volvo ECU.

Per email from Larry Hofer, the GXi ECM works well with his 525 and 600hp kits.

I do have a local guy that swears he can hack the ECM... but I havent connected with him yet on this.

I'd like to try running one of these 8.8's on a test stand using the VP ECM if possible... just to experiment and play around with tune/software before it gets anywhere near the boat.

Problem is, much of this depends on this garage im trying to build and it's already a month behind schedule.
I cut a check for $44,500 back in December and all I have to show for it is a big hole in the yard. I may own a Kubota skidloader too if they dont soon get back out here for it.

Just sent him a message.

Thanks!

Im trying to keep it simple and avoid running aftermarket engine management if possible...

Larry Hofer says the GXi ECM is the way to go with his 525/600hp kits... so I assumed it wasnt too horribly bad.

Cant you get a name from Larry or send it to Larry to sub out to reprogram?

Larry said he cant do anything with the newer Volvo Penta ECM's... or I'd just have him program the existing Gi ECM. He's the one that suggested the GXi ECM.

I know others have been able to get into them and reprogram, but that's on a "who you know" basis and I'm just a nobody in the boating industry.
I've already emailed numerous go-to names and they all say the same thing... "we cant program those"

There is a local guy here that says he can do it... but we haven't been able to connect yet... and I still have my doubts.

no one will post a video or say they can do it because everyone has gone underground its still there but not discussed on web sites or videos as the epa has folks reading and watching the web then go after them with a vengeance theres many videos of shops being raided by a swat team

At this point I'd say your easiest route is aftermarket engine control.

This is why I wont mention my local guys name.

The whole locked-down ECM thing I think is complete crap... as I OWN the item in question and should be able to use and/or modify it however I choose... No different than changing jets in a carb or twisting the distributor... but I understand what you are saying. "Loose lips sink ships"

What doesnt make sense to me is why certain ECM's can be tuned, and others are verboten and cursed.

Spoke to John the other day and yes, he can work on these ECM's if needed, but cant do anything with the tune other than load a factory tune.

This EPA stuff is really a bunch of BS.

We have stuff like HP Tuners and a few others for modifying tunes on cars... yet NOTHING for marine use. Heck... even my 2020 Tundra can be tuned via HP tuners.

Looks like I will be stuck with running the factory VP GXi tune or going to some aftermarket engine management system unless my local guy can do something with it.

These do not coincide.

Griff,

What is the phrase....? Cubic Dollars....?

Thanks. Brad.
(937)545-8991

I think there are a re few proven weak points on these 8.1's that can be improved upon rather cheaply.

The HO cams are on ebay @ $300 so I grabbed one of those and a couple spares to hang on to. They are bigger than anything Comp Cams offers in marine cams.

I found the 8.1 GXi ECM and harness in one of the facebook groups. Saw a guy had a VP GXi engine he was repurposing for his truck... so I asked if the ECM and wiring were still around. Got it for $550 shipped to my door. May or may not need the harness... but it looks like the ECM is a close enough mfg year that it will plug right into my existing harness.

On a side note... I HAVE spoken to exactly two guys that are familiar with these newer VP ECM's and both tell me it can be tuned.

If I knew what software to buy, I would just do it myself. I really wish HP Tuners would dive into the marine industry.

Found this thread looking for an ecm with your part # just curious if you decided to keep the original ecm if not would you be interested in selling it thanks please give me a call @513-503-6641 my name is Dave.

Volvo Penta 8.1 gi to gxi if you got it to work?
 

I was wondering if you gat the switch from a gi to a gxi done and worth the effort