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Dominick
Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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The saga continues. Replaced the high pressure fuel pump and

Customer Question

The saga continues. Replaced the high pressure fuel pump and fuel injectors. Runs much better but will not run full throttle. One plug looks brand new. The others look like they have been firing. Voltage to fuel injectors is 12.75 to 3 and 12.45 to plug
that looks unfired. thoughts.
Submitted: 1 year ago.
Category: Boat
Expert:  Jason replied 1 year ago.
Hello, Jason here.
You wrote "Voltage to fuel injectors is 12.75 to 3 and 12.45 to plug"
Are you only getting 3 volts to one of the injectors, am I reading that right?
Customer: replied 1 year ago.
No, three injectors are at 12.75 volts and the one is 12.45 volts. The three spark plugs look like they are firing but the one plug looks brand new.
Customer: replied 1 year ago.
Starting well, running but just not at full throttle.
Expert:  Jason replied 1 year ago.
There are 4 things you are going to want to do here.
1. Compression test the engine.
2. Spark test the engine with an adjustable spark tester
3. Use a stethoscope and see if the injector on that cylinder is clicking. But make sure it doesn't sound funny compared to the other 3
4. Lastly, and this is only if everything above looks normal, throw a dirty plug in cylinder that you don't believe to be firing. Run it a bit, and then remove the plug and see if it has gotten any cleaner.
Customer: replied 1 year ago.
Compression test is 155 on all four cylinders.
Customer: replied 1 year ago.
Injector is new and not clicking. Don't have a "spark tester" How long do you have to run it with the dirty plug in the questionable cylinder??
Expert:  Jason replied 1 year ago.
If the injector is not clicking move it to a different cylinder, and move one from a cylinder you know is clicking and place it in the original spot and see what happens.
Customer: replied 1 year ago.
I am not sure I understand. Is the injector supposed to be clicking???
Customer: replied 1 year ago.
I assume this is with the motor running and not at what we have for full throttle now.
Expert:  Jason replied 1 year ago.
Yes they should all be clicking. If the injector is not clicking it's not going to be firing. That's way I say swap it for one that is clicking and see if the non-clicking injector now clicks or not. That will tell you if the injector is bad. Or, if there is an ECM/Code/harness issue. Does that make sense?
Expert:  Jason replied 1 year ago.
Hello. Just checking in. Any luck swapping injectors?

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