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No start condition 2002 Malibu Wakesetter VLX


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JeremiahTRD
Posted (edited)

At ignition key on position there is no power to high pressure fuel pump.    I have tested the fuse and relay by swapping parts and testing.  No pressure on fuel pressure gauge at fuel rail confirms no power to pump. 

 

I tested the fuel injector wiring with test light and don't appear to be getting power to injectors while cranking. 

I have tested neutral safety switch.

I'm getting spark at plug wires.  

 

Symptoms before it quit completely.   Boat would always start right up at launch.  Would run well for an hour or so.  After it was good and hot it would  start to stall at idle.   Then eventually would not start back.  

Last year I felt like this was a vapor lock issue and water on fuel pump and waiting for a bit and the boat would run again.  

I assumed boat would start up today after it had cooled down again. But it's a no go.   I'm wondering if me dumping a bunch of water on the fuel rails and fuel pump yesterday caused another problem?  

 

   

Edited by JeremiahTRD
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7 minutes ago, JeremiahTRD said:

No pressure on fuel pressure gauge at fuel rail confirms no power to pump. 

A volt meter  or test lamp will confirm no power to the pump.  No pressure simply confirms that the fuel system isn't working correctly.

 

8 minutes ago, JeremiahTRD said:

I have tested neutral safety switch.

By what method?  A meter?  Bypass it with a clip lead or jumper wire to make sure.

10 minutes ago, JeremiahTRD said:

I'm wondering if me dumping a bunch of water on the fuel rails and fuel pump yesterday caused another problem? 

It is always possible that you have a bad connection at the fuel pump.  It is also possible that you have a bad pump, especially if yours is almost 20 years old.

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On the 5.7 engine with the MEFI4 ECM there are three 20 amp fuses with a clip on cover on the wiring harness near the ECM.  One is for the ECM power, one for the fuel pump relay, and one is for the starter relay.  Make sure you have power going across each fuse with the key on.

The fuel pump harness plug has a grey and black wire.  At key on, the grey wire should have battery voltage for several seconds, the black wire should always be connected to engine ground.  The fuel pump relay 30 pin with a pink wire gets battery voltage from the 20 amp fuse whenever the key is on.  The relay 86 pin pink/black wire and relay 85 pin green/white wire get power and ground from the ECM for several seconds at key on, or when the engine is running, to energize the relay coil.  The relay 87 pin grey wire will have battery voltage when the relay coil is energized and provides power to the fuel pump.

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electricjohn

Safety lanyard in? Is it cranking but won't fire?

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JeremiahTRD
7 hours ago, justgary said:

A volt meter  or test lamp will confirm no power to the pump.  No pressure simply confirms that the fuel system isn't working correctly.

Yes I tested with a volt meter  fuel pressure was gauge just confirmed no voltage at pump.

By what method?  A meter?  Bypass it with a clip lead or jumper wire to make sure.

It is always possible that you have a bad connection at the fuel pump.  It is also possible that you have a bad pump, especially if yours is almost 20 years old. 

 

 I tested the fuel pump with direct 12v power and it turns on and starts building pressure. 

 

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JeremiahTRD
7 hours ago, electricjohn said:

Safety lanyard in? Is it cranking but won't fire?

If I unplug the lanyard and try to start the boat the  gauges won't power on.   I think the starter wouldn't engage either but can't remember. 

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JeremiahTRD
7 hours ago, csleaver said:

On the 5.7 engine with the MEFI4 ECM there are three 20 amp fuses with a clip on cover on the wiring harness near the ECM.  One is for the ECM power, one for the fuel pump relay, and one is for the starter relay.  Make sure you have power going across each fuse with the key on.

The fuel pump harness plug has a grey and black wire.  At key on, the grey wire should have battery voltage for several seconds, the black wire should always be connected to engine ground.  The fuel pump relay 30 pin with a pink wire gets battery voltage from the 20 amp fuse whenever the key is on.  The relay 86 pin pink/black wire and relay 85 pin green/white wire get power and ground from the ECM for several seconds at key on, or when the engine is running, to energize the relay coil.  The relay 87 pin grey wire will have battery voltage when the relay coil is energized and provides power to the fuel pump.

The 3 Fuses have been tested by ohm meter for resistance and also by checking voltage at key on. There are working properly.   

As I understand it the 3 relays will work interchangeably.  So I swapped the relays around.   If I had a bad relay than the starter would not work when I plug that ignition  harness into the fuel relay and It did not stop working.      I swapped them around a couple different times.   

Still no power to fuel pump.  

I guess I don't see the need to test the power coming in and out of the relays  if when I swap it the starter relay for the fuel relay and my starter still works wouldn't that confirm the relay is working?  

If I know I have power thru the fuse to the relay I suppose it could be a ground issue somewhere?    

If I'm not mistaken the ground goes thru the ECU correct?   

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Good troubleshooting  collaboration ! I am wondering if the pump is just kaput. I think what I would try first, with extreme caution would be to apply 12V directly to the pump to see if it will spin up at all. Of course have a known good working fire extinguisher close by and hopefully a 2nd person. CYA clause.

Steve B.

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JeremiahTRD
1 minute ago, Steve B. said:

Good troubleshooting  collaboration ! I am wondering if the pump is just kaput. I think what I would try first, with extreme caution would be to apply 12V directly to the pump to see if it will spin up at all. Of course have a known good working fire extinguisher close by and hopefully a 2nd person. CYA clause.

Steve B.

Yes I put 12v external power to the pump.  Pump turns on and starts building pressure. 

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ECM thinks it should not send power to the pump. Is there an alarm going off all the time? I'm wondering now about oil pressure switch may be telling ECM not to say ok.

Steve B.

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JeremiahTRD

I don't hear any alarms or see anything on the dash?         As I understand it the oil pressure switch doesn't do it's check until after the engine is started. 

  Upon key switch to one click right, the pump should be getting power to build fuel for a couple seconds. I think. 

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Have you confirmed the ground on the black wire to the pump, voltage to the pink wire at the relay, and the ground and voltage at the green/white and pink/black wires at the relay from the ECM?  Even if the relay is good that doesn't mean you are getting the power and ground to the relay that is needed to make it energize.

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10 hours ago, JeremiahTRD said:

I don't hear any alarms or see anything on the dash?         As I understand it the oil pressure switch doesn't do it's check until after the engine is started. 

  Upon key switch to one click right, the pump should be getting power to build fuel for a couple seconds. I think. 

Yes, you are right about that. It should energize on key up.

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Similar to cstleaver's comment, are you sure you have a good connection at the fuel pump relay?  I saw this issue in a 2004 VLX with the monsoon.  We thought the issue was the fuel pump relay, but it turns out it the connector the relay plugs into wasn't making a good connection and therefore not energizing the fuel pump.

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2 hours ago, cla10beck said:

Similar to cstleaver's comment, are you sure you have a good connection at the fuel pump relay?  I saw this issue in a 2004 VLX with the monsoon.  We thought the issue was the fuel pump relay, but it turns out it the connector the relay plugs into wasn't making a good connection and therefore not energizing the fuel pump.

iirc i had a similar failure: pin backed out of the relay socket.

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JeremiahTRD
16 hours ago, csleaver said:

Have you confirmed the ground on the black wire to the pump, voltage to the pink wire at the relay, and the ground and voltage at the green/white and pink/black wires at the relay from the ECM?  Even if the relay is good that doesn't mean you are getting the power and ground to the relay that is needed to make it energize.

Black wire to pump is grounded,     at Key on I  have 12 volts to both pink wires at the relay.      Green/White wire gets grounded at key switch on.        I get zero voltage from the grey wire at any time.   Which I don't understand.  If i have power and ground to the relay and the relay works fine when its switched over to the starter circuit?                   I have checked continuity from the grey wire from the relay to the fuel pump    It tests fine no shorts.                

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JeremiahTRD
4 hours ago, cla10beck said:

Similar to cstleaver's comment, are you sure you have a good connection at the fuel pump relay?  I saw this issue in a 2004 VLX with the monsoon.  We thought the issue was the fuel pump relay, but it turns out it the connector the relay plugs into wasn't making a good connection and therefore not energizing the fuel pump.

I checked  continuity on the grey wire thru the relay connector  and it tests good.

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Posted (edited)

A bad crimp or compromised/broken wire may show low resistance in an ohm test if it is still making some contact, but may not be able to carry the load of the circuit.  Look closely at the pins and crimps on the grey wire at the connectors.

An old trick to see if the relay is being energized is to listen for it to click or use a small handheld compass very close to it.  The energized magnetic field of the relay will cause the compass needle to quickly move.

Edited by csleaver
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JeremiahTRD

Found the Problem.       My testing and diagnosis was all done properly and led me to believe it was the ECU.    I took it by my buddy's boat mechanic shop and he hooked it up to the computer.    

The ECU came up saying

ECM Calibration memory checksum failure

Pump Low/Open

We can manually cycle the fuel pump thru the diacom.     

We called MEFIBURN and they confirmed it was a problem inside the ECU.     They think they can reflash my existing ECU   so here's hoping they can fix it.

They think its a bad ground or power wiring issue which caused a failure.   So I will be going thru my harness and inspecting cleaning everything up.

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The older MEFI1 and MEFI2 were known for having some issues with the circuit that powered the fuel pump relay, that is why the MEFI4 provides a ground to the relay instead.  When the MEFI1/2 became unavailable, a common fix for a failed fuel pump ECM relay circuit was to install an oil pressure switch to power the relay instead, in the same way the carbureted boats did it.  If the your ECM can not be fixed, a similar solution may work with a bit of wiring modification.

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