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Recent content by vroomZOOM

  1. V

    454 MAG mpi chugs/stalls at idle - running lean

    fuel pressure is constant 45psi all the time. Both wire harnesses work fine on the other engine. Both sets of injectors work fine on the other engine.
  2. V

    454 MAG mpi chugs/stalls at idle - running lean

    Alternator case to battery ground is about 0.03 volts difference. Alternator output to ECU is 0.8 volts tops. Alternator positive to battery positive jumps around depending on if cranking or running but never goes more than +- 0.5V
  3. V

    454 MAG mpi chugs/stalls at idle - running lean

    Here is what I tested right now: ECM positive (orange) to battery positive - 1.2V while cranking, 0.3 volts while it was running for the short period of time. Doesn't go past 0.3 volts when it stalls. Negative about 0.2 volts when running and stall between ECM ground and battery negative...
  4. V

    454 MAG mpi chugs/stalls at idle - running lean

    Tried swapping the jumper from the coil to the ICM. No luck there. I put a multimeter between the grounds on both engines and got about 0.03 volts, which tells me the big ground cables are in good shape. will test the positive cables now too.
  5. V

    454 MAG mpi chugs/stalls at idle - running lean

    That is how my boat is set up. The port engine only charges its own battery, and the starboard charges its battery and the house battery. The voltage traces were with the new alternator.
  6. V

    454 MAG mpi chugs/stalls at idle - running lean

    Yes I have diacom. Here are some snapshots of diacom when I try to start the engine: All the numbers look ok, MAP reads baro at 30 in hg. Relays stayed in the harness and I also tried swapping them out. I also tried running witht he alternator disconnected but no use.
  7. V

    454 MAG mpi chugs/stalls at idle - running lean

    No, it never ran right. Previous engine also ran like this. I thought the issue was in the longblock so I got a new one. Separate harness and key switch aka boat in a box, see picture
  8. V

    454 MAG mpi chugs/stalls at idle - running lean

    S/N 0L394105 (serial number is off the identical starboard engine, tags are missing off the problematic port engine) Hello, trying to figure out a 454 mag mpi horizon that chugs and stalls and won't idle. It will start up every time, and instead of settling to idle it will stall out. I have a...
  9. V

    Mercury Axius questions

    Hi, need someone knowledgeable on the axius systems to give me some info. Long story short: lots of parts for the gen 1 system are NLA. I can still get TVMs and CCMs for the gen 2 system. Then there is also the axius joystick piloting (gen 3), joystick piloting (gen 4), and joystick piloting V2...
  10. V

    Quick tricks to diagnose prestolite BID?

    Hello, dealing with a backfire on a 7.4GL with prestolite BID system. Is there any way to test the individual components to figure out the faulty one? The engine backfires through the carb like crazy when under power. Or is it time to go to a different system? Thanks
  11. V

    Mercruiser 3.0 flooding

    Hello I have what seems like a common problem but I couldn't find a solution. So anyways I ran my engine (2000 3.0) after a carb rebuild. First time after rebuild fired up, no issues, runs great. Ran it the next day, to make sure before going out boating, and it ran great for 15 mins or so and...
  12. V

    what do I do before cranking up a 115 opti that was sitting a while

    aha! now I have found something... All the plugs are like this. with the sooty band on the insulator. Are they SUPPOSED to be like this??? IMO not... Would that cause the misfiring? Anyways the injectors are out and there's only 3 of them and they are like $20 each to clean so I will do that and...
  13. V

    what paint colour is a 2008 df200?

    title says it all. What colour is the lower and upper cowling on a 2008 DF 200? I see three different ones that have different names that mean the same thing!
  14. V

    Mercruiser 3.0 Thumping in exhaust

    Hello My 3.0 is making funny noises, most noticeably a clacking from the camshaft area it seems and a thumping in the exhaust. Have a look at the video. It ran like crap above 3800 rpm on the first time out this year, then it started running like crap at idle. I swapped out the plugs and it got...
  15. V

    dent in my aluminum boat, how do I go about fixing it?

    Hello I am sure this has been asked a bunch of times, but i'd like some specific advice. My boat has a dent (not really a dent but bent in area from the previous owner constantly slamming the boat into the trailer bunks). He tried to silicone the crap out of those rivets, but of course, that's...
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