fuel pump relay not getting power

[Ts87]

My names is Tim and I have a 2001 Mastercraft X-Star with an Indmar LTR 330hp engine.* I just purchased the boat and it ran fine on the test drive.* I brought it back home*and it pulled 3 wakeboarders fine, then on the 4th the engine started to stutter.* We packed it up for the day and went back out to the lake 2 days later and it had the same issues almost immediately.* The 50 amp circuit on the engine kept tripping, if i reset it engine would start up and run again.* The stutter will vary, sometimes right after hitting the throttle, sometimes it would run for 90-120 seconds and then bog down.* Then we decided to float and my wife left the stereo on and it drained the battery.* Got a tow back to the dock and brought the boat home.* That night I opened the fuel tank and the gas smelt bad.* I drained the gas tank, charged the battery and cleaned the air filter.* Went out to the lake the following*day and the boat wouldn't start.* Went home*and started to test things.* The fuel pump was not getting power, check all 3, 15amp fuses and the fuel pump fuse was blown.* I opened my fuel tank and pulled the pump unit to find that the negative terminal had come off pump, at this point I thought the pump might be bad so I bought a new one.* Tested both fuel pumps directly to battery and they both work.* Put the new fuel pump in since I don't know how long the old one had been in there and since I had already bought a new one.* Replaced the fuse for the fuel pump also.* Pulled both the ECM and Fuel Pump Relays and they are both functioning.* Reinstalled everything in the boat and turned the ignition to on, no fuel pump prime.* Took off the ECM relay and verified it is getting power with voltmeter, it is.* Reinstalled ECM relay and pulled the Fuel Pump Relay, it is not receiving power.* Having trouble finding the wiring diagram for this boat.**

But my question is, does the fuel pump relay get power from the ecm?* Does this sound like I have an ECM problem or could it be something else?* I just want to make sure I check everything before sending the ECM in to have it diagnosed.* Engine still tries to crank over but not starting due to lack of fuel.* Ran a fuel pressure gauge and getting 0 psi due to the fuel pump not getting power.* Sprayed some starting fluid on the air filter and it will start briefly from the starting fluid and then die from lack of fuel.

Thanks for your help

[skydyvyr]

Um, have you verified the safety switch? Make sure the lanyard is on? I’m not sure if on your model it interrupts both fuel and spark or not, but that is always the first place I look after working electrical on my engine.

Yes, wiring diagrams are not available for these boats, so no easy solution there.

When chasing down gremlins I get my fluke meter out, disconnect connectors and start doing continuity checks... not particularly fun, or quick, but it is the only way I know to try to figure out what is connected to what if I can’t get the knowledge for more experienced people here on the board.

—Sky

[StingrayDad]

Fuel pump relay should be triggered by a ground through ecm. Terminals 30 and 86 should be powered with key on.(this is on relay terminals) Terminal 85 should go to ecm and when triggered the ecm grounds that terminal to turn on fuel pump relay. Terminal 87 should go to fuel pump. It gets power from terminal 30 when relay is triggered.


Sent from my iPhone using Tapatalk

[Ts87]

That is great to know. Thanks for the info StingrayDad. I checked terminal 86 and it was not getting power. I will check to see if 30 is getting power also and chase those wires back to see if i can find my problem. I thought that terminal 86 was getting power from the ecm and then triggering power to fuel pump.

Thanks Skydyvyr, I have checked the safety lanyard, it is functioning. That was my next step was to do continuity checks. I was hoping it wasn't going to result to that but that may be how i spend my long weekend instead of on the lake.

[88 PS190]

Agree on continuity testing - when a fuse blows sometimes other things can go bad,
I believe on your boat its MEFI-3 and in that case the ECM relay energizes the fuel pump relay (not through the ECM) so you should have power out on pin 87 of the ECM Relay that then goes into the fuel pump fuse then into pin 30 on the fuel pump relay.

So if you don't have power on fuel pump pin 30 I'd do continuity to ECM relay 87

ECM Relay 87 is in turn powered from battery to ECM relay 30 from its fuse. So you can sort of trace back through.

[Ts87]

Ok so I ran home at lunch and made some progress. Made jumpers to separate the relay and test. I’m getting power with ignition on to 85 and 30. The ground path back to ecm (pin 86) is bad and not triggering the connection between 30 and 87. I ground 86 to engine block and my fuel pump came on. Tested with fuel pressure gauge and I have pressure to the rail. Good.

Now to fix the faulty path of 86, the ground back to ecm. Is there a main wire coming out of ecm for the ground that I can check and clean up? If so what PIN number and port 1 or 2? Or is this a sign my ecm is failing and it’s time to send it in to be tested?

[StingrayDad]

I think you found the problem. On my 04 x-star the fuel pump control is j2-09. Wire is dark green with white stripe. But my ecm is a mefi-4. I don’t know if they are the same.


Sent from my iPhone using Tapatalk

[Ts87]

I have continuity back to ecm. So I’m thinking it is ecm failure? Anyone see anything I’m missing?

[StingrayDad]

I’m assuming you mean continuity between 86 and j2-09? If that’s the case I would say ecm needs some repair.


Sent from my iPhone using Tapatalk

[Ts87]

Correct. Mine is j1-23. But yes continuity between j1-23 and 86 on the fuel pump relay.

[mikeg205]

An unclean ground can cause a number of problems. You may have continuity but it could be a dirty connection. ECMs usually work or completely fail.

Also, check the battery cables, they may look ok, but could be corroded on the inside, causing a dirty ground.



Sent from my SM-G955U using Tapatalk

[StingrayDad]

There is a company called Technical Services that can repair these (ecm). I believe they are located in Indiana and sometimes post on this site. Hope I was able to help.


Sent from my iPhone using Tapatalk

[Ts87]

Update in case anyone is wondering. I sent my ecm off to OBD Diagnostics in California. Great shop they were able to diagnose in less than 2 days. My ecm is fried, they think it was a voltage spike that caused the issue. Shipped me out a new ecm same day. Highly recommend if you are having ecm problems. New one should be here monday, so hopefully a water test monday afternoon. (Have to love having a lake 10 mins from my door.)

[Ts87]

Well case still open... Plugged in the new ecm and no luck, still no power to the fuel pump. Brought it to a local shop to have another set of eyes look over it. I'm stuck, anyone else have any ideas??

[lakedrum03]

Check the following:

With batteries on, do you have power to the pink wire in at the fuel pump relay?

With the key on, do you have the same?

With the key on, do you have ground to at the green/white strip wire at the relay?

When you turn the key on, is your fuel gauge working?

If not any any of those, then it may be the lanyard switch. It is just a two pin plug so you should be able to jumper it out to check it.


Anything other than that then you may need to start teating apart harnesses and checking for broken wires.