GM Marine 454 EFI swap

[Larry]

I just scored a complete brand new marine variant (Mercruiser MPI) L29 454 fuel injection manifold with the fuel rail, injectors, throttle body, etc to bolt on to my crate 454HO in my 78 K10. It is complete and even powder coated per marine specs. The Ebay god was good to me.

Being that GM Marine stuff (Mercruiser, Volvo, etc) do not have emission controls (no EGR, etc) I am thinking of running a Mercruiser marine wiring harness, ECM and calibrations apposed to using an automotive PCM from a L29 C/K truck (same engine as my avatar). The light truck L29 only produced 290 HP while the same engine in marine form produced 340 HP running on OBD I data. There is a sea of more power available with marine.

I know LS1tech.com is pretty good but they don’t seem to deal with much marine stuff since the LS1 family of engines have not been used in any marine applications until very recently.

Have any of you heard of anybody doing a Marine EFI swap like this into a vehicle? Websites,etc

BTW….I tried the search function to no avail….

Thanks

 

[sled_dog]

Not surprised on the search function. I know one or two guys have dealt with this swap but not posted it, or they haven't actually done it yet.

Check out, Fullsizechevy.com or thirdgen.org. I know Ryoken is a Marine Tech and could probably help, I'm sure he'll check in when he seas the word Marine. I've seen people on Fullsizechevy do marine intake swaps on Small Block Vortec motors. Don't know otherwise. Sorry I'm not more help.

 

[big pappa b]

I have picked up a similar unit, a Mercruiser MPFI unit for my big block. It came off a 502 Scarab boat. The swap is straight up. I was lucky enough that my came was almost identical to the one the 502 was running so my ECM won't need to be changed

 

[ratzila]

Try Arizona speed & marine
http://www.azspeed-marine.com/

 

[ryoken]

hey Larry...

i play with that stuff daily, tho i've never swapped to a vehicle..... like the boys said, the swap should be pretty straightforward... i've just acquired a sb setup for the stroker i'm gonna do.. but haven't researched it at all yet...

if you have any specifac marine questions, i have all the service manuals.. also have the wiring diagrams...

 

[Larry]

Thanks ryoken….

Wiring diagrams, I will defiantly need. I am planning on buying a Seloc Mercruiser service manual for the sake of wiring diagrams, fuel pressure specs, etc. I also found a decent online Mercruiser parts catalog at Mercruiserparts.com to help figure out common GM parts vs Marine while doing research for this project. It seems this marine stuff has a lot in common with the GM Performance Parts RamJet line of engines, such as being an open loop speed density operating type EFI system. No EGR, no O2, no Mass airflow sensor, etc.

A few questions…..Does Mercruiser run OBDI that can be read with a GM type TECH I scan tool, flash codes out with an indicator lamp and paper clip or is the operating system Mercruiser proprietary that requires special software…..like those phukers at Cummins Engine Co???? (I hate Cummins….not the product…but the company, they suck).

Is the marine ECM mounted on the engine or away from a heat source? In other words, do I need to mount the ECM in the cab or is under the hood OK like the 1996 to current GM vehicles? Where is the ECM mounted on a boat for 1998 and later non-TBI GM powered units? By looking at the Mercruiser wiring harnesses available through their service parts org it appears using the engine and ECM wiring harnesses should be pretty easy to adapt to the truck. I am also considering running a GM Marine style fuel pump too before the dual fuel tank switch valve. Any thing you can tell me about marine fuel pumps? Do they absolutely need to be water-cooled??

I work for a truck manufacturer that uses mainly GM Powertrain (Workhorse Custom Chassis) and have contacts within GM Powertrain but my contacts seem pretty far separated from the GM Marine division. I am also well used to working with late model GM Powertrains but I know nothing about BOATs (Bring Out Another Thousand….as they say).

Here is the Ebay link to my score. Yes, I paid more than I wanted too, but I figured I would never find another NEW Marine emissions free L29 intake ever again. Plus, it is something different than what most others are running. My Silverado is paid off next month so I guess I didn’t feel so bad about blowing $500 for my play truck.

I guess I am a bit nervous because this marine swaps appears to be too easy….So, why are more people not swapping marine EFI systems onto their rigs and forgetting about TBI swaps??

I already have my Gen VI 454 set up like a 1999 C/K L29 (less MPI) anyway so this Marine injection setup should work pretty darn well….I hope. I am so dang tired of high altitude carburetor problems like flooding, starving, running fat, etc.

 

[ryoken]

i'm not certain if its OBD1 actually.. merc has a tool with light indicators to check codes.. i've only used it once, honestly most probs we run across are mechanical failures. water-injestion, stuck valves, etc... the EFI systems seem quite durable and troublefree.. the tool isn't big bucks, think it was between 50 and 100.. i'll check into it today for ya..

the ECM units are standalone, mounted to the exhaust manifolds. so underhood on firewall, etc would be fine. tho i would think in the cab would only be better..


the fuel pump mounts on a bracket near where a mechanical would.. well, except the watercooleds... specifacs on it, i can't tell ya.. just a standard looking electric inline.. watercooled, tho nice, shouldn't be nescesary. the early EFI's wheren't...

here's a few diagrams for ya..

 

[ZooMad75]

Just got my latest 4 wheeler mag in the mail the other day and one of the contestants in Top Truck is running a 454 Marine setup. Not much detail on it (other than to say it was a marine 454) but the website might have some more indepth info.

Great info ryoken. I'm going to be helping out with the swap once Larry gathers all the parts. I've got a Tech 1 scan tool so if there is a way we can use it to check codes and operating parameters it would help. I'll have to do some digging to see if we can or not.

Keep the info coming!

 

[Larry]

ryoken,

I really appreciate your help. Zoomad and I will probably have to pick your brain a lot until this project is complete.

Do you have any good sources to purchase a Marine L29 ECM for cheap. Seems like all that I have found are from $600 to $1100.

 

[ryoken]

no prob.... i'll check on a price for that tommorrow.. pretty much all our Merc stuff comes from Davidsons..

we're supposed to become a Merc dealer ourselves, but my boss has been procrastinating over the 10 to 20 g's ya have to lay out... could be a good gig, but we're hesitant cuz ya get lousy labor rates initially... and tho i prolly have 100 boats with Merc, we honestly don't need the additional warranty work. being full service, we're always swamped to begin with..

but anyway, forgot to check on the scantool today, but i'll look into that and the ECM tommorrow... if your having trouble buying anything Merc related i can get you anything and prices should be as decent as you'll find or better...

feel free to pm me anytime fellas....

 

[Larry]

Well, here is the main ingredient of the L29 MPI fuelie goods. I was pretty disappointed the clown that I bought it from on Ebay threw it in a box full of packing popcorn allowing the crap to find it’s way into virtually every orifice of the manifold.

Not very impressed with the FedEx Ground contractor that heaved it on my front porch in front of me either especially after I met him on the front step because he was a day late per the FedEx website. I about poke him in the eye when it clanged when it hit the ground. Stupid FedEx Ground and Home Delivery contractors. Make note to self….send stuff UPS or REAL FedEx….not Ground or Home Delivery.

After unpacking it and blowing out the stupid popcorn it appears this unit has never been used before. Yayy! Now, the real work begins as far as tons of research and part accumulation. Bet, I’ll have her goin by spring.

http://chevytruckworld.tenmagazines.com/gallery/Larry/199349.jpg

 

[dyeager535]

There is a guy over on thirdgen.org (s10wildside?) that had success getting the Ramjet engines to run in closed loop operation, so I would imagine he'd be a good resource. He posted quite a bit about his dealings with a Ramjet. My understanding is that the Ramjet's are essentially marine engines anyways, they were never factory installed in any land vehicles of course.

The power increase isn't going to be from anything other than engine hard parts. The things run in open loop, so it's preprogrammed fuel. The driveability and economy will never be what they can be because of that, but with no restrictions on emissions, and the entirely different application, it is easier to make power. Stuff in a bigger cam, program the ECM to run it safely in all operating conditions (never go lean) and you are done. Can't do that with something that needs to run as clean as possible for emissions.