Removal of MEFI 4 system from 6.2L V8

BigChris

Seaman Apprentice
Joined
Apr 25, 2016
Messages
39
So here's my story, in 2011 I bought a very low hours immaculate condition Four Winns Horizon 220 with a cracked block and cracked exhaust manifolds. The previous owner, who recently relocated from Florida, failed to winterize the engine and well......she froze. I bought her knowing this, and the selling/buying price reflected this.
I am an engineer by trade, the son of a Snap-On tool man, I build race engines for dirt oval go karts as a side business (www.rperacing.com). I've repowered boats, cars, jet skis, snowmobiles before. I have a bridgeport in my 1000 square ft shop on my property. I'm pretty mechanical.

The original engine was 5.0L with the MEFI 4 system. So off to the junkyard I went, and grabbed a couple 5.7 liter small blocks. I bought the Eagle racing 383 kit from summit, and built a properly clearanced marine engine. .003" piston to cylinder wall with hypereutectic, .030" top ring gap, .035" second ring gap, 9.8:1 compression ratio. Valve train is designed to handle 6500 rpm, though it'll never see it.

I sent MEFI 4 computer off to Jim at Az Speed and Marine to have it reflashed. Disclosing the manifold was from a 305, and it had injectors from the original 305.
Bought the Rinda diagnostic tool to be able to set cam retard via the distributor, and verify ignition timing.

She starts amazing. She pulls out of the hole real strong. Top speed of 60mph, at 5200ish rpm (says the dash tach).

But here's my problem...........top speed run (WOT, flat water, perfect trim) she's tulipped the intake valve on #3 cylinder twice on me now.

I've verified fuel pressure 48psi, and replaced the injector on #3 cylinder after the first time. The second time was late last summer after a nice weekday high speed run at Raystown (there's nobody there on the week days).

So I've had it, since I lack the equipment to diagnose and reprogram the computer, and after several polite phone conversations with Jim S at AZ speed and Marine that went nowhere, I'll be converting this system to a carburated setup. I'll be removing the manifold, throttle body, fuel pump assembly, computer and crab style distributor. Those items will go for sale on ebay along with the Rinda tool.

I'll be replacing them with a mechanical fuel pump, Edelbrock intake manifold, Edlebrock 650 cfm carb, and a MSD HEI distributor. (carb and dist will of course be the marine type).

My plan is to document this effort here.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,465
Ayuh,.... Welcome Aboard,... Sounds like a Plan, but I'd probably go with a Delco Voyager distributor, insteada the MSD,...

The Voyager is inexpensive, 'n super reliable,....

It's the Go To, when replacin' a T-Bolt system,.....
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,581
Howdy

Sounds great and look forward to seeing the change. I don't have warm or fuzz with AS&M, they have a nice sounding name and appear to do good work with auto, but they are not marine guys.

It's a shame your scrapping it all, there wasn't many MEFI-4's and to fix your issue you would need a laptop, MEFI burn SW and oxygen sensors to put in the exhaust. To setup your carb correctly it would be best to also use sensors in the exhaust for the initial jetting
 

BigChris

Seaman Apprentice
Joined
Apr 25, 2016
Messages
39
Thanks for the suggestion Bondo. I like how that comes as a kit from Marine Engine Depot complete with timing jumper harness. I assume this is the one your talking about.
http://marineenginedepot.com/MP/Mar...5.7L-350ci---7.4L-454ci-GM-Delco-Voyager-EST/

AllDodge, I talked to him about the "cam retard" setting being set to 45?-48?, and he didn't quite follow that adjusting (twisting) the distributor wasn't setting ignition time. It was then I realized I was not going to get anywhere with him. That being said, I fear my injectors (from stock 305) may simply not be up to the task of delivering the right amount of fuel, I asked him if he could recall what my reflashed settings were and he couldn't. I spend a good chunk of change on that reflash. It's a bummer, b/c at one point I was really exited about building a computer controlled multi port fuel injection hot-rodded V8. That love affair is over. I wont bash the guy anymore. Just wont ever go there again.
 

BigChris

Seaman Apprentice
Joined
Apr 25, 2016
Messages
39
Thanks Bondo. So after math homework (my 10 yr olds) I made a bunch of progress disassembling last night. Here's about where I started.
IMG_6660.JPG

Here's about where I ended. The MEFI 4 complete wiring harness has been removed and each of the connector labeled where they go. Manifold, coil, distributor, fuel pump/filter assembly, and valve covers have also been removed.
IMG_6668.JPG

But here's where I humbly need some help from those who know more than me....
Here is the connector I have remaining on the boat's harness.
IMG_6665.JPG

Here is the connector that came off the MEFI 4 harness.
IMG_6672.JPG

So a quick ebay search for "volvo penta V8" wiring harness yielded nothing with a connector that looked remotely like this. So I then searched for "Mercrusier V8 wiring harness" and found a bunch with this connector.
Can someone point me in the right direction of which one I need, I'd like to do the least amount of cutting and splicing...... If you need more information please let me know, I did not "pin it out" i.e. whihc pin gets which colored wires.

The boat is a 2005 Four Winns Horizon 210, it originally had a 5.0L Volvo Penta with the MEFI 4 system.

Thanks in advance.
 

Attachments

  • IMG_6660.JPG
    IMG_6660.JPG
    127.6 KB · Views: 3
  • IMG_6660.JPG
    IMG_6660.JPG
    127.6 KB · Views: 3

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,581
Not VP guy but that plug appears different then the Merc 10 pin plug (VP left, Merc right).

plugs.jpg
I'm sure you could buy the engine harness from VP dealer which would be the first thought. Looked up a GL model (thinking this is a carb motor) and found the engine harness for $969. Or get a Merc Boat pigtail fro $50 and a custom engine harness for $149.

http://www.cpperformance.com/c-146-wiring-harnesses.aspx
 

BigChris

Seaman Apprentice
Joined
Apr 25, 2016
Messages
39
Thanks for your thoughts AllDodge, after some further research, I found the VP 10 pin is listed under VP SX wiring harness. ​http://www.ebay.com/itm/2005-Volvo-...ash=item3f61694937:g:GuYAAOSwo0JWHWoF&vxp=mtr I'm wondering if this might work, same vintage, but a 4cyl instead of a V8. Looks to be carb, (I'm not sure the 4cyl were fuelie). I'm thinking basic sensors should be the same, just might have to extend certain wire lengths. Your thoughts?
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,581
Would probably work and would guess you would have to extend most the wires.

Ya know Merc has an engine harness and an EFI harness. The engine harness connects to all the regular stuff you normally think of. The EFI harness plugs into the engine harness at the engine and controls fuel injection and everything else. The engine harness is on all EFI and non-FI engines.

So my thought is VP might have the same setup. Look at your harness closer, maybe :noidea:
 

BigChris

Seaman Apprentice
Joined
Apr 25, 2016
Messages
39
I get what your saying. The main harness I took off is wrapped together electrical tape, so it's entirely possible there are two harnesses in there. Perhaps it's just "bundled" together in there and can be separated. I'll check it out tonight, thanks for the tip!
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
To late to edit the wiring should just plug and play below is what work's for the dizzy,your just disabling the mefi controller and enabling the on board dist module.

attachment.php




attachment.php
 
Last edited:

BigChris

Seaman Apprentice
Joined
Apr 25, 2016
Messages
39
Tail_Gunner, whelp I went to an "expert" and fully disclosed the equipment I had including: cam, compression ratio, heads, displacement, manifold and injector by part number. (using the supplied form) I trusted an established business. Spent $400 clams on reflashing the ECM, and the time, effort and parts to repair-twice.

So this time, I'm going to change it so I can tune it.

When you say the wiring should just plug and play, are you talking about the ebay harness I posted a link to in post #8?
If so the one thing I wonder about is the temp sensors on the exhaust manifolds. Obviously a 4cly will have one where I have two. I understand they essentially a thermally variable resistor, are they in series or parallel? How are they wired?

AllDodge,
I attached a picture of the MEFI 4 wiring harness, yesterday I started to unwrap the electrical tape. While the harnesses may be able to be separated, they are not (what I consider to be anyway) obviously independent. I'm not saying your wrong, I'm just saying I'd rather not completely unwrap the whole thing. I'm trying to think of the "resale" value of this, and fear I make devalue it. (especially if I can score a used one for around $100-$130)



I've attached two pictures. The first is the wiring harness, yesterday afternoon. The second is the cylinder head from last late summer/fall when I had my last problem. (take a look at the color pattern on #3 cylinder's intake valve)

IMG_6678.JPG
IMG_5271.JPG
 
Last edited:

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,581
The 4cyl may only have one sensor in the thermostat housing, but if it's ne enough it would have two. One for the gauge and one is a switch to set off an alarm/buzzer.

As before I mentioned that Merc does this but didn't know about VP. That said, the wire length in your current harness will work without splicing. My "guess" and again no VP guy, but it could probably be used and just re-route a couple and cut and cap others.

I'll bow out because I'm just guessing and maybe TG will fill in the blanks
 

BigChris

Seaman Apprentice
Joined
Apr 25, 2016
Messages
39
Thanks for all your thoughts AllDodge. I really appreciate it.

I wasn't tal king about coolant temp, but the brown wires going to the risers/elbows on the exhaust. It's a brown wire with a 90? rubber straight push on connector. II'm pretty certain they are overtemp warnings for the manifold/risers. On a V6/V8 there are two present, but one the 4 cylinder there is only one. I'm thinking how do you convert a harness with only one of these to a harness w two.
This guy, see below
wiring harness question 042916.jpg
 

Attachments

  • wiring harness question 042916.jpg
    wiring harness question 042916.jpg
    296.2 KB · Views: 0

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,581
As before listening but trying to let those more knowledgeable answer: It takes an ECM to read and the exhaust temps, and a myriad of other sensors. A carb engine has no sensors other then the normal ones (oil pressure, water temp, outdrive lube, and a couple more maybe). So the temp sensor in the exhaust will not be used with a carb motor.
 

BigChris

Seaman Apprentice
Joined
Apr 25, 2016
Messages
39
AllDodge, again I appreciate your help, but that pic above was from the carb 4 cyl harness that was on ebay. I bought that harness, and we'll see how it goes, if a v6 or v8 harness pops up, I may just buy that and sell the 4 cyl harness. Please understand I'm not criticizing you, I understand this isn't your area of expertise, and I do truly appreciate your help.

I guess at this point I wanted to see: a) what mods will be needed to make this harness work, b) if everything will function as intended (gauges and accessories) b) how much modification the harness will need to lay neatly on my engine.

So last week I ordered the following:
mechanical fuel pump, bronze tip fuel pump push rod, gasket (summit)
pump to carb fuel line (summit)
Fuel filter assembly and bracket (marine engine depot)
analog temp sensor (marine engine depot)
thermostat housing (ebay)
thermostat (marine engine depot)
Edelbrock 1410 carb, electric choke (used, ebay)
Spark arrestor 10" x 2" ( marine engine depot)
Voyager distributor and Coil (marine engine depot)
Carb to throttle cable quick disconnect fitting (marine engine depot)

You might ask why did I buy another thermostat housing? Well when I sell the MEFI 4 system, I plan on doing that as a complete unit. Including fuel cell (pumps and filter), harness, ECU, intake manifold with throttle body complete. I feel this will make the system more desirable than parting it out.

Here's a progress picture
engine w manifold installed.jpg
 

BigChris

Seaman Apprentice
Joined
Apr 25, 2016
Messages
39
So the UPS man brought a bunch of goodies yesterday. I haven't gotten around to being assembling yet. But I did take inventory.

I have a question regarding the Voyager Distributor. It came with a wiring diagram explaining wiring for installation, simple and straight forward. I downloaded this and read it:

https://marineengines4less.com/image...?1431462059320

From what's listed in the table on the bottom of page 7, I have a question. See pic:
timing chart.jpg

For the V8 Distributors (the one I bought) is showing a 16? to 20? advance........ (305 is 24-8=16 or the 454 is 30-10=20)

The distributor I bought: http://marineenginedepot.com/MP/Mari...o-Voyager-EST/


I understand the procedure to set base timing.

So my question is, how much advance should I expect out of this distributor? 16 or 20?

Or do I split the difference and set base to 12? and see what total is?

BTW My target total is 30? BTDC. True vortec center bolt valve cover heads 12558062 casting number.
 
Last edited:

BigChris

Seaman Apprentice
Joined
Apr 25, 2016
Messages
39
Been making some progress on my project.

Engine rotated with cylinder #1 at TDC and distributor installed. Sort of a little disappointed with this unit. No real clear manual included other than a wiring diagram. No reference for base timing other than the online manual that's listed above (which I believe to contain some errors). No markings on the distributor cap for which cylinder each terminal is for, I had to label it with a sharpie. Overall the feel and "heft" of this unit does not impart that it's a robust, well constructed component that cost $377. Time will tell.

New thermostat and thermostat housing installed. Need to grab different "long" bolt for the thermostat housing, the one I got was too long.

New mechanical fuel pump installed.

Carb and spark arrestor temporarily installed for mock up and clearance checks.

To do list:

Fabricate mounting bracket for fuel filter/water separator.

Pumb fuel, fuel path will go tank, filter/water separator, pump, carb.

Wiring harness mock up, modifications, and final install.

Throttle cable bracket fabrication.

Rebuild raw water pump. Had a slow drip end of last season.

Draw on harmonic damper degrees for setting timing and total advance check. Damper is 8.015" dia. So (8.015 x 3.14159)/360=.070"/degree on damper.

Contemplating whether or not I want to put chrome valve covers on it or not.

IMG_6715.JPG
 

Attachments

  • IMG_6715.JPG
    IMG_6715.JPG
    123.5 KB · Views: 2

BigChris

Seaman Apprentice
Joined
Apr 25, 2016
Messages
39
I am at the point in this project where I am laying out/installing the wiring harness from the 4 cylinder GL.
Please see the attached diagram, just a couple questions.
Question #1
Item #6 is electric choke, correct?
Questions #2
The purple wire that connects to red/purple at the alternator then goes to the starter solenoid 10 pin connector & coil. Explain this to me please. Y/R is "start" from the ignition switch, red and orange are battery positive. As I understand it, the purple is 12v positive from the keyswitch when ignition is "on". What is this terminal/connection at the starter solenoid for?
Question #3
What is item #22? I'm thinking this was a resistor used in a different coil than the AC Delco voyager I have.
Question #4
Items 13, 18, & 20 are alarms? Normally open? when switch to closed they cause an alarm at the helm? 13 is water temp alarm at thermostat housing, 18 is exhaust manifold water temp at riser elbow, and 20 is oil pressure down near the oil filter? Do I have that right?

Thanks in advance,
Chris image_243992.jpg
 

Attachments

  • 2011-08-12_175125_3.0gsc.jpg
    2011-08-12_175125_3.0gsc.jpg
    347.2 KB · Views: 5
  • 2011-08-12_175125_3.0gsc.jpg
    2011-08-12_175125_3.0gsc.jpg
    347.2 KB · Views: 4
  • 2011-08-12_175125_3.0gsc.jpg
    2011-08-12_175125_3.0gsc.jpg
    347.2 KB · Views: 2
  • 2011-08-12_175125_3.0gsc.jpg
    2011-08-12_175125_3.0gsc.jpg
    347.2 KB · Views: 3
Last edited:
Top