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  #21  
Old 09-09-2021, 08:42 AM
jpwhit jpwhit is offline
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I've seen this story before, you've had a series of issues and have thrown parts at the problems, including some parts that may not be exact OEM equivalents / specs. I suspect at this point you have compounding issues at play.

My recommendation would be to find a good marine mechanic that has a complete set of diagnostic tools and let them get everything "right" during the off-season. And by right, I mean watch things like fuel pressure curves during accel and decel, Diacom to watch all the ECU live monitors, and the tools to watch both ignition primary and secondary voltage curves. Then they can systematically get the fuel and ignition system to perform as intended by watching those measurements.

In the end having an expert go through everything will likely be cheaper and less of a headache in the long run.
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  #22  
Old 09-09-2021, 10:20 AM
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Quote:
Originally Posted by robadele View Post
You may have already checked this, but any chance your fuel pressure is now too high? This would explain your plug fouling. Your earlier posts stated you've had to make a lot of repairs to the fuel system and at one point the fuel pressure was too low. Have you taken a fuel pressure reading while running?
Going to take a fuel pressure reading this weekend at idle and under load. I haven't done that since replacing the fuel rail regulator.
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  #23  
Old 09-09-2021, 10:25 AM
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Quote:
Originally Posted by jpwhit View Post
I've seen this story before, you've had a series of issues and have thrown parts at the problems, including some parts that may not be exact OEM equivalents / specs. I suspect at this point you have compounding issues at play.

My recommendation would be to find a good marine mechanic that has a complete set of diagnostic tools and let them get everything "right" during the off-season. And by right, I mean watch things like fuel pressure curves during accel and decel, Diacom to watch all the ECU live monitors, and the tools to watch both ignition primary and secondary voltage curves. Then they can systematically get the fuel and ignition system to perform as intended by watching those measurements.

In the end having an expert go through everything will likely be cheaper and less of a headache in the long run.
All parts replaced have been exact OEM replacement parts except for the fuel rail regulator which I got at Napa after removing the OEM one that came on the engine. The new Napa part is a direct replacement down to the part number.

I agree that if I could find a "good" marine mechanic to to a complete set of diagnostic tests I would have the boat in that person's shop ASAP. However, I have not been able to find that person. The dealers just hook up their computer and read codes and swap out parts depending what codes they get. Therefore, I am left to diagnose the issues myself and try to fix it.

Yes, having an expert go thru everything would certainly give my peace of mind and be less stressful than doing what I'm doing now.
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  #24  
Old 09-09-2021, 10:56 AM
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waterlogged882 waterlogged882 is offline
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Quote:
Originally Posted by prostar205 View Post
All parts replaced have been exact OEM replacement parts except for the fuel rail regulator which I got at Napa after removing the OEM one that came on the engine. The new Napa part is a direct replacement down to the part number.

I agree that if I could find a "good" marine mechanic to to a complete set of diagnostic tests I would have the boat in that person's shop ASAP. However, I have not been able to find that person. The dealers just hook up their computer and read codes and swap out parts depending what codes they get. Therefore, I am left to diagnose the issues myself and try to fix it.

Yes, having an expert go thru everything would certainly give my peace of mind and be less stressful than doing what I'm doing now.
I share your sentiments (above).

Tombstone - famous line by Wyatt Earp - "You're not as stupid as you look Ike."

No reference to your looks...merely the gest of the subject matter. You're spot on.

Best on the solution.

Following to learn.

.
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Last edited by waterlogged882; 09-09-2021 at 11:34 AM.
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  #25  
Old 09-09-2021, 01:39 PM
chrislandy chrislandy is offline
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Quote:
Originally Posted by prostar205 View Post
If the ETC sensor was bad, wouldn't that give me an overheating condition on the engine temp gauge on the dash? The boat runs right at 160 degrees all day long.

I'm leaning towards several stuck injectors but I am suspect that 5 of the 8 injectors are all stuck open or clogged open.
It depends on whether you have separate senders for the gauge and the ECU, it's quite common for the ECT to read show a higher resistance e.g. the resistance is interpreted as say 140deg rather than 160, therefore the ECU throws a bit more fuel in as it thinks its running cold. This ends up with sooty plugs but doesn't necessarily lead to rough running. This can be from a poor connection, breaking down wire, sensor breaking down etc it only needs a few Ohm increase to make a massive difference to the reading.

99% of the parts on the engine are standard automotive parts, so I wouldn't worry about what you've already done, the main marinized parts are the alternator, starter and ECU - but the sensors, rails, regulators, injectors etc are all automotive.
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  #26  
Old 09-09-2021, 02:09 PM
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This weekend I will be taking fuel pressure readings at idle and various RPM ranges. I will also try to find the ECT and take some resistance readings in different water temps. I will also pull the injectors and have them all cleaned. There is a company local to me that does this type of work. They have done work on my 1969 Barracuda and 1999 Expedition that I swapped in a Lightning supercharged 5.4L into a few years ago.
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  #27  
Old 09-09-2021, 04:02 PM
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Table Rocker Table Rocker is offline
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When the coolant temp sensor is telling the ECM the engine is cold, it runs richer until it warms up, simulating the choke on carbureted engines. It is a fairly common failure point and a relatively inexpensive part.
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  #28  
Old 09-09-2021, 06:19 PM
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prostar205 prostar205 is offline
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Quote:
Originally Posted by Table Rocker View Post
When the coolant temp sensor is telling the ECM the engine is cold, it runs richer until it warms up, simulating the choke on carbureted engines. It is a fairly common failure point and a relatively inexpensive part.
I know where the temp sensor is that feeds the engine temp to my temp gauge on the dash. Its right next to the thermostat housing.

Does anyone have a picture or know the location of the ECT on an 8.1L (2002)?

I assume I have 2 different temp sensors - one that feeds the MMDC for the dash gauge and one that feeds the ECM for the fuel injectors.
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  #29  
Old 09-09-2021, 11:05 PM
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Quote:
Originally Posted by prostar205 View Post
II assume I have 2 different temp sensors - one that feeds the MMDC for the dash gauge and one that feeds the ECM for the fuel injectors.
My boat is older, so... On mine there is a temp sender for the gauge, one for the ECM and one that is skinny that is a switch for the light on the dash. The one for the ECM probably looks like this:

https://skidim.com/sender-water-temp.html
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  #30  
Old 09-10-2021, 01:22 AM
chrislandy chrislandy is offline
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Yes, thats the one, it's quite a thin sensor and has 2/3 wires coming from it.

it should be in the side of one of the heads normally tucked next to or under a plug - but may be in a different location.
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