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Ask K. Kergan Your Own Question
K. Kergan
K. Kergan, Marine Mechanic
Category: Boat
Satisfied Customers: 1030
Experience:  24 yrs exp. Inboard/Outboard mechanic Mercury/ Mercruiser, Volvo Penta and OMC, Johnson/Evin.
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Can you help me troubleshoot a Volvo penta 4.3 L GXI-e?

Customer Question

Can you help me troubleshoot a Volvo penta 4.3 L GXI-e?
Submitted: 1 year ago.
Category: Boat
Customer: replied 1 year ago.
Scanner reveals code 81 fuel rail B low voltage. It then repeated with high voltage. When the code was cleared , reboot the scan tool without restarting the engine and the same code reappeared.
Customer: replied 1 year ago.
Fuel pressure good. Compression good. Motor starts but runs rough and at low. Rpm
Expert:  Jason replied 1 year ago.

Hello my name is ***** ***** am I speaking with?

Do you have a DVOM to measure the resistance of each fuel injector?

Customer: replied 1 year ago.
This is Jon. I am the boat owner not the mechanic. I have general knowledge but I am looking for guidance on the next step. I am trying to avoid having to buy a new $1700 EC you as the mechanics are suggesting. What is a DVOM.?
Customer: replied 1 year ago.
Should the mechanic measure the resistance of each injector? What are they looking for?
Expert:  Jason replied 1 year ago.

Hi Jon. DVOM is Digital Volt Ohm Meter. Code 81 can mean a few things from a bad ECM to a shorted injector. Step 1 would be measuring all 8 injectors and seeing if any of them show a short. Is that something you can have done and get back to me?

Customer: replied 1 year ago.
sir. Thank you. Give me a day or so
Expert:  Jason replied 1 year ago.

Sounds good, let me know what you get for readings on each injector and we can take it from there.

Customer: replied 1 year ago.
Had mechanic go back today. All injectors read the same and no shorts to ground. Next step?
Expert:  Jason replied 1 year ago.

Got it. The next thing would be to measure the voltage at each bank of injectors with the engine running. Do you know what the actual votlages are reading?

Customer: replied 1 year ago.
I'll check with him. Jason the mechanic is suggesting maybe I swap the computer from one engine to the other what do you think about that? Not trying to jump the gun in terms of your diagnostics
Expert:  Jason replied 1 year ago.

I would personally check the voltages before swapping the ECM.

Customer: replied 1 year ago.
Customer: replied 1 year ago.
Do I risk any damage to ECU by swapping?
Customer: replied 1 year ago.
Jason, what should the voltages read?
Customer: replied 1 year ago.
Jason, am I referred to a new person?
Expert:  K. Kergan replied 1 year ago.

Hi, my name is Kerry

I don't know what your voltages should be, I don't have a manual, however I can tell you

that swapping the ECUs won't hurt them. Just make sure you disconnect the batteries before

unplugging anything.

If the problem moves to the other engine, you have an ECU to replace.

If it stays on the same engine you have some other problem, possibly a sensor.

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