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PCM GT-40 Computer Issues

Up NorthUp North Posts: 19 Baller
Hi everyone,
After doing some troubleshooting on a friends boat, we have determined that the computer needs to be repaired or replaced, and have not gotten anywhere in finding a solution.

The problem is that the relay associated with the fuel pumps (second one in the circuit) is not energizing for the brief period after turning the key on, like it is supposed to. It seems like the input to the computer is supposed to create a briefly held ground path for the relay to be turned on, but isn't. I have verified this operation on my boat with the same engine, and after installing my boats computer in his boat, his runs great.

Long story short, I have not researched this a lot yet, but he has called everyone from a Correct Craft dealer, PCM, Discount Inboard Marine, and a couple ECM repair places he found on the internet and hasn't gotten anywhere.

The story he is being told is that they do not make these any longer, and has not found anyone who can help him out or point him to a solution.

Because there are a lot of these boats still in service and running strong, I have to believe someone has a solution for this, and thank you in advance for your feedback.

Have a great day!


  • AndreAndre Posts: 986 Crazy Baller
    edited June 2017
    To help others help you,you way want to post year of the engine and a pix of the ECM serial and model numbers.
    Good luck!
    Have you tried with @Jody_Seal and Indboard sulutions (not sure of the name ) ?
  • whitecapswhitecaps Posts: 22 Baller
    Check Plantetnautique. There is a thread on there about programming a different ECM to be used on the GT-40. It has been done with success. Hope I don't need to deal with it personally but I do know you aren't the only one that's gone down this path.
  • JayG80JayG80 Posts: 92 Baller
  • rockdogrockdog Posts: 492 Solid Baller
    Correctcraftfan likely also will have a thread related.
  • A_BA_B Posts: 3,980 Mega Baller
    I went through the same thing with my ECM. Ended up getting a new one. There is a rebuild place online, but at that point, I was tired of chasing the issue and just popped for a new one.

    Possible Rebuilder
  • Jody_SealJody_Seal Posts: 2,415 Mega Baller
    I have one, but it ain't cheap!! $1500
    Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise.

  • Orlando76Orlando76 Posts: 713 Crazy Baller
    Seems like there's two choices: Jody Seal, or swap over to a carb.

    I can't necessarily say I'd switch to a carb quite so soon unless there's other issues. But a properly tuned carb is flawless.
  • JC McCavitJC McCavit Posts: 490
    @Jody_Seal - How many years did PCM build the GT-40? Is the 300-M new or used? Can you get more when you sell the one you have?
    JC McCavit
  • Jody_SealJody_Seal Posts: 2,415 Mega Baller
    @JC McCavit
    I stumble across GT engine's all the time currently I am in possession of three ECM's however only one of them is a 300-M and one of the others has hot soak issues (wont run the pumps after it reaches a certain temp).
    None are new, even PCM has only one on the shelf for diagnostic purposes.
    Gt-40 years roughly 1995-2002.
    Another place to look is Volvo Penta as they also utilized the same ECM.
    The common failure in these are the fuel pump drivers.
    Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise.

  • JC McCavitJC McCavit Posts: 490
    edited June 2017
    @Jody_Seal - Thank you for the information. I wish PCM would make some more, it's hard to see how it wouldn't be profitable with so many of the GT-40 engines in use.
    JC McCavit
  • oldjeepoldjeep Posts: 3,073 Mega Baller
    Choice 3 might be an aftermarket injection kit. About the same price as Jody's ECM but at least there will be longer term parts support ford-marine
    Chuck P
    Not a mechanic but I play one at home
    [Deleted User]
  • Jody_SealJody_Seal Posts: 2,415 Mega Baller
    A lot more to it then just installing that kit:
    replace intake manifold also another $250, gaskets $50. and if ya are not in possession of the correct squeezers and twisters or don't know how they work then it becomes more of a $2500-$3000 job if it rolls into a shop for the conversion.

    Also have had some experiance with these aftermarket EFI systems. they are ok in a vehicle but the fiddle factor in a marine application especially for a ski boat becomes very apparent. but if that is all one has to do and it is a hobby then by all means let rip Taterchip!!!

    All of a sudden that $1500 ECM looks good especially when in less then 5 min it can be changed out!!
    Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise.

  • eleeskieleeski Posts: 3,584 MM Trick Skier / Eccentric Person
    I've put aftermarket electric fuel pumps in cars. I wonder if you could replace just the fuel pump?
  • AndreAndre Posts: 986 Crazy Baller
    edited June 2017
    If it's indeed the fuel pump driver all the fuel pump need is another source of 12 volts to run.There is a way to fix that for someone with a bit of mechanical/electrical knowledge
    But i would try to get in touch with the guy from the planet nautique thread linked before.
    That would be my first choice.
    1500$ US is a lot of cash for me...
  • DanEDanE Posts: 823 Crazy Baller
    Beware of scrapping the ECM just because the fuel pumps don't run. If the symptom is that they won't run unless you are cranking the starter there is a diode hidden in the harness that can break and cause this. Study the wiring diagram and rule this out.
  • Up NorthUp North Posts: 19 Baller
    The fuel pump relay is energized for a few seconds when you turn the key (at least it is supposed to). The relay is turned on by a ground being created in the ECM that temporarily energizes that relay which in turn energizes the pumps. I am not sure if that same ground is created once the engine starts or if there is another means that powers the pumps at that point. If it is just needed when the key is turned initially, a switch could be installed that would need to be manually be turned on and off again, but I am guessing that same circuit is used once the engine starts and would need to be shut off to stop flowing fuel to the engine in a normal or emergency shutdown.
    Anyway, it is this circuit in the ECM that is the issue
  • thagerthager Posts: 4,261 Mega Baller
    I had a similar problem this spring with the Excaliber engine. Energize system but no fuel pump pressurization whine noise. Crank the engine all you want but no start. Problem for me was bad connection on back of kill switch. Wire spade connection to post was not tight and had a little corrosion on it,
    Stir vigorously then leave!
  • A_BA_B Posts: 3,980 Mega Baller
    edited July 2017
    Don't rack your brains on this like I did. Throw a fuel pump gauge on the rail and if the pump fluctuates it is the ECM having a brain fart. Mine would hold pressure and then fluctuate and the engine would sputter. I replaced the pumps, relays, and something else. Jody is right on as usual.
  • DWDW Posts: 1,837 Crazy Baller
    @Mark_Matis : How do you like the AFI system? Pros / cons (performance / fuel economy)? Any issues? Thx.
  • AndreAndre Posts: 986 Crazy Baller
    Congrats on saving 1k !
    That's a lot of ski rides!
  • shansen345shansen345 Posts: 171 Baller
    There are many shops out there that will program EFI systems to run on standalone aftermarket ECUs. I have a hard time believing that a reputable tuning or speed shop could not make someone a new ECU for their GT40.
    I am hoping to buy a GT40 boat within the next few years, so I appreciate you sharing your positive result with us. Glad it worked out for you.
  • @Up North -What year is your friends GT-40, do you know if your friends ECU is a 300-M or the older version? I have a 1997 with the older ECU and would like to have it upgraded to the specs of a 300-M ECU.
    JC McCavit
  • Mike9812121298Mike9812121298 Posts: 6 New Baller
    Just throwing it out there for anyone looking for a gt40 ecu, check out last I checked they have some in stock
  • JC McCavitJC McCavit Posts: 490
    I am not a able to view the products area, something about not having a valid security certificate.
    JC McCavit
  • Mike9812121298Mike9812121298 Posts: 6 New Baller
    take a look now I added a buy it now button on the home page. I'll have to look into the security certificate issue, i haven't seen that on my end
  • JC McCavitJC McCavit Posts: 490
    @Mike9812121298 - are the ECMs the 300-M version? The products tab on your website is working now.
    JC McCavit
  • Mike9812121298Mike9812121298 Posts: 6 New Baller
    Yes there uploaded with the most up to date firmware. 300-M
    Please let me know if you find anything else about the site. Still trying to work out the kinks
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