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2021 Axis Boat fuel injector issue


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Hi all,

I have an 2021 axis with 200 hours, and recently started to see fault code with Spn 651. I would normally just reset battery and this would go away, but now it’s there every time I turn on the engine. The indmar manual is showing Injector 1 - short to power
 

I had a mechanic change out the fuel injector, but the active fault code is still there. Anyone else had issues similar to this? Others have mentioned the issue is probably with electrical wiring to the injector shorting out but I’m not exactly sure where to start. Any advice is greatly appreciated!

 

 

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Unfortunately I’m no where near by a Malibu dealer that can service the boat so I’m looking for way to take care of this myself or with a local mechanic..

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8 hours ago, wakeywake said:

Unfortunately I’m no where near by a Malibu dealer that can service the boat so I’m looking for way to take care of this myself or with a local mechanic..

You didn't specify the FMI that occurs with the suspect parameter, but since you have changed the injector it might make sense to use the correct tool to remove the contacts from the connectors and carefully inspect the crimp job.  You want to make sure that nothing looks out of place and it has no stray strands of wire that didn't get in the crimp properly.  You will need to inspect both the injector end and the ECM end of the harness to make sure that they both are OK.  While you have the ECM connector off, you might also want to use an Ohm meter to test the resistance of the harness to make sure that the wires are not somehow shorted to each other.

I don't know which pins on the ECM drive that injector, but perhaps one of the guys that do know will help from here, e.g. @csleaver or @COOP

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On 10/1/2021 at 4:58 AM, wakeywake said:

Hi all,

I have an 2021 axis with 200 hours, and recently started to see fault code with Spn 651.

 

What engine is in your Axis and what is the FMI number on the fault code?

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16 hours ago, justgary said:

You didn't specify the FMI that occurs with the suspect parameter, but since you have changed the injector it might make sense to use the correct tool to remove the contacts from the connectors and carefully inspect the crimp job.  You want to make sure that nothing looks out of place and it has no stray strands of wire that didn't get in the crimp properly.  You will need to inspect both the injector end and the ECM end of the harness to make sure that they both are OK.  While you have the ECM connector off, you might also want to use an Ohm meter to test the resistance of the harness to make sure that the wires are not somehow shorted to each other.

I don't know which pins on the ECM drive that injector, but perhaps one of the guys that do know will help from here, e.g. @csleaver or @COOP

may be completely off here, but my hunch was that since this fault code started to gradually pop up slowly over time rather than all at once, it most likely wouldn’t be a wire shorting? Could it be any other issue other than electrical harness that I should consider before opening up to test the wiring/resistance again? Accessing the injectors on my M5di engine is a bit of PIA 😅

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Just spoke with a dealer and they suggested i use diacom to remove the fault code, especially if I’ve already replaced the injector. Is there another way for me to remove the active fault code without the software? Or is clearing the fault code just putting a temp bandaid on the problem?

Edited by wakeywake
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The SPN 651 FMI 5 will set if the ECM detects low feedback voltage on the number 1 injector coil while the injector drive circuit is in the off state.

The first steps recommend in the diagnostic support manual is to start and run the engine, clear the system fault (Rinda Diacom or TechMate are used to clear faults), then see if the DTC occurs at idle.  If the DTC does not occur then it is considered an intermittent fault.  Most intermittent faults are caused by voltage drops from loose or corroded connections.  I would check the engine grounds first, but any loose connections can cause a problem.

If the DTC occurs at idle then the injector, harness, and associated ECM circuit need to be tested.

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8 hours ago, csleaver said:

The SPN 651 FMI 5 will set if the ECM detects low feedback voltage on the number 1 injector coil while the injector drive circuit is in the off state.

The first steps recommend in the diagnostic support manual is to start and run the engine, clear the system fault (Rinda Diacom or TechMate are used to clear faults), then see if the DTC occurs at idle.  If the DTC does not occur then it is considered an intermittent fault.  Most intermittent faults are caused by voltage drops from loose or corroded connections.  I would check the engine grounds first, but any loose connections can cause a problem.

If the DTC occurs at idle then the injector, harness, and associated ECM circuit need to be tested.

Thank you @csleaver

to clarify - when you say check engine grounds, I’m checking for the any loose cables on the engine ground ? (which is located in the lower front port side)?

Also what is considered associated ECM circuit for this injector?

Edited by wakeywake
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The engine grounds to focus on are on the port side bellhousing stud, but I have seen the battery ground connected to the port top bracket near the alternator on some engines.

The SPN 651 FMI 5 fault is set by a open loop in the injector or a short to ground on the LS (low side) of the circuit.  The 12 pin molex C19 injector harness connector for the odd bank (for injector 1) is on the starboard rear of the intake manifold near the flame arrestor.  Pin 5 is the LS for injector 1 and goes to the CRI1A-LS on pin 91 of the ECM connector.  A reading of less than 5 ohms between this circuit and the engine analog ground or battery ground is considered a short to ground.  If there is an open loop in the injector, a short to ground in the harness, or a faulty ECM internal circuit, then the SPN 651 FMI 5 fault will continuously set at idle.

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Always back probe or use the side of the pin when testing harness connectors.  Inserting a test probe into the mating surface of any connector pin can damage the pin, create intermittent failure, and likely affect the warranty on the associated harness.

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10 hours ago, csleaver said:

The engine grounds to focus on are on the port side bellhousing stud, but I have seen the battery ground connected to the port top bracket near the alternator on some engines.

The SPN 651 FMI 5 fault is set by a open loop in the injector or a short to ground on the LS (low side) of the circuit.  The 12 pin molex C19 injector harness connector for the odd bank (for injector 1) is on the starboard rear of the intake manifold near the flame arrestor.  Pin 5 is the LS for injector 1 and goes to the CRI1A-LS on pin 91 of the ECM connector.  A reading of less than 5 ohms between this circuit and the engine analog ground or battery ground is considered a short to ground.  If there is an open loop in the injector, a short to ground in the harness, or a faulty ECM internal circuit, then the SPN 651 FMI 5 fault will continuously set at idle.

Thank you @csleaver

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@csleaver I connected to the boat to the diacom and deleted the fault codes. Then I turned the boat on again and the service light came back on with the same code, so this is an issue sitting at idle. Diacom is showing open loop circuit

in this case, I will measure the resistance from both LS pin 5 vs ground, and pin 91 vs ground. If there is an open loop from either of these, what do I need to do? Would I also need to check LS pin 1 and also pin 61 on ECM side?

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According to the diagnostic guide you should check for an open circuit in the injector, and a short to ground in the harness to eliminate those from the possible cause.  There is no direct testing for the ECM described.

I usually complete the testing, note my results, and contact the factory service representative for confirmation, pre-approval of the repair, or additional recommend testing.  Your dealer will be your best bet if a harness, injector, or ECM is needed for the fix.

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My dealer is 3.5 hours from my house. It’s a long ways. Even longer if there’s Portland traffic. No way I’d take the chance of fixing the boat and only making it worse. Then taking it to the dealer and expecting them to fix the problem that might have been made worse by you or your local mechanic. At this point, I would bet your local dealer won’t even touch it now. Not trying to be a jerk, but that’s why they come with a warranty. 
 

None the less, good luck with getting it fixed and back on the water.  I have a diacom diagnostics tool if you need to borrow one.  

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Just an update

- opened up the engine, tested the pins on the injector harness from injector side to connector side. Circuit is there on pin 1 and pin 5

- tested against the back wire of connector to the injector side wires, circuit is there 

- tested against ecu side 61 and 91 against pin 1 and 5. Circuit is there 

Also found out my previous mechanic changed injector 2 instead of 1.. (port side instead of starboard side). Sigh

Changing out injector 1 now as this looks to be the main culprit after process of elimination. Will revert back

 

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Update 2 - accessing the fuel injector myself was a piat, especially having to unplug the fuel lines. Testing the wires/cables for resistance was relatively easy and quick, and actually swapping out the injectors took only few min 

Replaced the injector #1, put the engine back together and all is back to normal. Wished indmar designed the engine in a way where you don’t have to unscrew the ECM, coolant, fuse box and the manifolds just to access the fuel injectors. All in all, great experience in this little DIY experience and learned a ton from you guys. Thank you again!

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