350 MAG MPI start-up

[achris]

Just finished putting together a 350Mag MPI after it filled 4 cylinders with seawater. Turned out to be a cracked exhaust manifold (after the owner didn't notice/ignored an overheat alarm). The engine got the full treatment - new pistons, bearings, lifters, pushrods, etc. I took a couple of days putting all the fruit back on and checking everything was good. I spun it over without spark plugs until the computer showed I had oil pressure, then in with the plugs, and connect a fuel tank... Let's see if it runs... (unable to throttle it up because...DTS...)

Chris........

EDIT: the 4% power available Guardian is due to the ECU failing to detect the throttle and shift controller, 'Canbus error'. When it goes back in the boat and the DTS cable is reconnected that will return to 100%

 

[Fun Times]

Nice job there Chris!!!:thumb: Pretty good you were able to find/locate the correct pins to use to jump the newer style 14 pin connector vs the old 10 pin design.

Haven't looked in awhile now, are the pins numbered or did you have to take some time to trace out the correct ones to jump for +-key-on-ignition and start wires? without using a remote switch something of this nature, https://www.amazon.com/MERCURY-REMOT.../dp/B00N9HLQL8

 

[achris]

Thanks Fun Times , the only pinouts I found on the interweb appear to be wrong. The pins are labelled A to N. The online, and even the Merc installation CD diagrams, call out pin A as +12volts, but it is not. Using a multimeter I found the only pin with any voltage on was H (marked in the pinouts as 'spare'). Looking at the back of the connector it has the right wire colour, so I found the only purple (colour of 'key on') on C, that got it fired up... I hooked the remote starter switch into the connector for the starter relay. Just unplugged the relay and connected the switch directly across. The ECU even detected the starter relay as unhooked. Clever I had a look at the codes and it also found no DTS controller, so popped an active code because of that too, and that's the reason for 4% power available.

Chris........

 

[QBhoy]

Chris...love this video and great to hear your voice.
Love watching guys with talent show their stuff.
Yeah...the faults showing might just be the usual inherent mpi ones that usually show without the corresponding sensors. There are a few.
Chris...whilst you have this thing in bits...do you reckon there is a grease nipple on the output shaft, inboard of the transom ? I’m sure I saw one on my mpi and certainly had one on my old 4.3.s...but the local merc dealer reckons I don’t. Suppose I shouldn’t be so lazy and have a right good look.
Anyway. Love the video.

 

[QBhoy]

Chris...I’m maybe preaching to the enlightened, but on the odd chance these 350’s MPIs are new to you, I have plenty of advice for you with pro active and re active fault deterrent. God knows I’ve seen them all.
Great engines, once you get the usual crap dealt with.

 

[achris]

Chris...love this video and great to hear your voice.
Love watching guys with talent show their stuff.

Thanks, I really like doing it too....

Yeah...the faults showing might just be the usual inherent mpi ones that usually show without the corresponding sensors. There are a few.

Just finished putting the engine back in (those B3 drives are HEAVY!) and all the faults cleared and the available power is back to 100% :thumb:

Chris...whilst you have this thing in bits...do you reckon there is a grease nipple on the output shaft, inboard of the transom ? I’m sure I saw one on my mpi and certainly had one on my old 4.3.s...but the local merc dealer reckons I don’t. Suppose I shouldn’t be so lazy and have a right good look.

Alpha One Gen II have a single grease nipple on the coupler extension/nose, the Bravo couplers don't have the extension/nose, and have 2 grease nipples.... It's one of the selling points Merc highlighted since the 90s...

Anyway. Love the video.

 

[achris]

Chris...I’m maybe preaching to the enlightened, but on the odd chance these 350’s MPIs are new to you, I have plenty of advice for you with pro active and re active fault deterrent. God knows I’ve seen them all.
Great engines, once you get the usual crap dealt with.

No, I might be an old dog, but I'm willing to learn new tricks. This guy is my only 'customer' (I only work on friends and relatives boats and cars these days) with a V8. All the rest are 4.3s.... This was also the first MPI I fully stripped. Interesting exercise, and it all went back together without a hitch. We sent the long block out to a specialist rebuilder and I just 're-dressed' the engine when I got it back... I have also found that the 4.3MPI and the 350MPI share the same genetics (both mechanically and electronically), so transferring knowledge was quite easy... Having had the Diacom software for quite a few years also helps a great deal. As far as I'm concerned, trying to fault-find an MPI engine without the software tools is a fool's errand... I also helps to use it as a 'dash board' when running the engines on a stand...

Thank you for the offer, and if I run into something, I'll certainly take you up on it.

Chris..........

 

[QBhoy]

No

No, I might be an old dog, but I'm willing to learn new tricks. This guy is my only 'customer' (I only work on friends and relatives boats and cars these days) with a V8. All the rest are 4.3s.... This was also the first MPI I fully stripped. Interesting exercise, and it all went back together without a hitch. We sent the long block out to a specialist rebuilder and I just 're-dressed' the engine when I got it back... I have also found that the 4.3MPI and the 350MPI share the same genetics (both mechanically and electronically), so transferring knowledge was quite easy... Having had the Diacom software for quite a few years also helps a great deal. As far as I'm concerned, trying to fault-find an MPI engine without the software tools is a fool's errand... I also helps to use it as a 'dash board' when running the engines on a stand...

Thank you for the offer, and if I run into something, I'll certainly take you up on it.

Chris..........

No problems Chris.
Not a total expert but have had more than most with regards to MPI issues and head scratching. Basically just as a result of the hours I put on the boat. Touch wood I have the better of the game these days.
Thanks for the pics of the coupler. I was certain I greased there last year or early this year. The merc dealer had me questioning myself. He reckoned the mpi and newer didn’t have one here. Maybe he was thinking of the new gimble bearings that are sealed.

 

[achris]

... He reckoned the mpi and newer didn’t have one here. Maybe he was thinking of the new gimble bearings that are sealed.

Yes the gimbal bearing, and the unis, are sealed and don't need greasing, but the coupler still does....

Chris.....

 

[QBhoy]

Yes the gimbal bearing, and the unis, are sealed and don't need greasing, but the coupler still does....

Chris.....

Good stuff. Thought I was going daft for a while. Wasn’t sure whether I was getting mixed up with my old carb mercs and VPs. Cheers.

 

[aimlow]

When you say MPI, which one? They are all just marinized versions of a stock GM unit. The worst are the CSFI systems used on Vortec trucks in the late 1990's.

 

[achris]

When you say MPI, which one? They are all just marinized versions of a stock GM unit. The worst are the CSFI systems used on Vortec trucks in the late 1990's.

This one is a Mercury PCM555, with DTS. Nothing 'GM' about it. It was developed by Motorola specifically for Mercury...

Chris...

 

[aimlow]

This one is a Mercury PCM555, with DTS. Nothing 'GM' about it. It was developed by Motorola specifically for Mercury...

Chris...

Sounds like GM hardware with a simple Motorola brain?

 

[achris]

Sounds like GM hardware with a simple Motorola brain?

Not at all.... The ECU is Motorola, the injectors are Bosch, the harness is Mercury (with Delphi connectors), most of the sensors are MotoTron, the relays and solenoids are Hella or Omron, the IAC is SMP...

BTW, what is your point?

Chris........

 

[aimlow]

Not at all.... The ECU is Motorola, the injectors are Bosch, the harness is Mercury (with Delphi connectors), most of the sensors are MotoTron, the relays and solenoids are Hella or Omron, the IAC is SMP...

BTW, what is your point?

Chris........

If the system is a variant of CSFI, it has an application specific distributor (flat topped) with unique characteristics. It was used on vortec engine GM trucks. Early versions used an electronic fuel distributor with fuel lines going to a pressure sensitive injectors, just like a Mercedes/Bosch system. GM developed a retrofit kit with electronic injectors to replace it.

 

[achris]

:facepalm:

I've googled the GM CSFI, and Mercury Marine MPI is nothing like it. NOTHING in common...

The CSFI system uses a single point 'spider' distribution unit with the injectors at the end of each leg. The Mercury system uses a hard pipe configured as a common rail, much like a 'ring main'...

 

[aimlow]

:facepalm:

I've googled the GM CSFI, and Mercury Marine MPI is nothing like it. NOTHING in common...

The CSFI system uses a single point 'spider' distribution unit with the injectors at the end of each leg. The Mercury system uses a hard pipe configured as a common rail, much like a 'ring main'...

That's the better system. They're both "multi-port", with injectors at the intake valve, but the CSFI system is more primitive and troublesome. The CSFI system is crank fired, but still utilizes the distributor.