No power to fuel pump

[Probably the Killswitch]

I have a 2006 XLV with the 5.7 Indmar EFI. I pulled the boat out of winter storage and it was running flawlessly for a couple weeks. The other night on the lake, I went to start up to go home and it started pretty hard. I had to pump the throttle quite a bit which I have never had to do in the 15 years I've had the boat. Thinking it was just the fuel/water separator that caused the hard-start, I changed out the cannister the next day only to find the boat would crank but not fire at all. I brought the multimeter down and discovered I am not getting power to the fuel pump. I started running down the list of possibilities and this is what I've done so far:

Checked fuses near the ECM- all good.
Removed all three relays and tested with multimeter- all good
Checked kill-switch connections and tested continuity with multimeter- good
Removed oil pressure sender and tested with multimeter- good
Checked for loose/corroded connections under dash- all seem fine

Most posts I have read on similar issues pertain to carb engines so I am at a loss for what to check next. Any help is appreciated.

[Turbinesurgeon]

So are you testing for voltage while cranking or just the 2 seconds it comes on when you turn the key on?
The crank sensor could cause this problem and worth looking into as well


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[Probably the Killswitch]

I'm checking it while cranking. I will take a look at the crank sensor. Do you know where it is located? I can't seem to find it on any diagrams.

[Holdmybeer]

I'm checking it while cranking. I will take a look at the crank sensor. Do you know where it is located? I can't seem to find it on any diagrams.

Under the water pump, just left of the harmonic balancer when looking at the belt drive. Probably a $30 part and a PITA to change.

You can check the resistance on the sensor. I believe you want to be under a 1000 ohms. Last one I checked new was 300-ish and the old one measured 6,000 (trash).

[Probably the Killswitch]

Thanks for the tips guys, I really appreciate the help. I'll give it a go after work and let you know how she does.

[Holdmybeer]

If you turn the key to run you should see 12V at the pump for 1-2 secs and/or even hear it build pressure. If the crank position sensor or oil level switch is bad, then it won't fire when you try to start the engine.

If there is not voltage at the fuel pump at all, then time to start looking at wiring back to the ECM and the ECM itself.

How did it run home once you pumped it to start? Crank position failing usually causes misfires and no power.

[Probably the Killswitch]

I'm getting no power to the pump whatsoever. I'll try to pull all the wires out of the conduit first to have a look at them. I'm hesitant to jump straight to the fried-ECM conclusion just yet but I'm stating to get to a point where it's not unreasonable.

Boat ran fine on the way home. Cruised at about 3K rpm for 10-15 minutes then came down to an idle without issue to dock. No spit/sputter or rpm weirdness.

[Holdmybeer]

I'm getting no power to the pump whatsoever. I'll try to pull all the wires out of the conduit first to have a look at them. I'm hesitant to jump straight to the fried-ECM conclusion just yet but I'm stating to get to a point where it's not unreasonable.

Boat ran fine on the way home. Cruised at about 3K rpm for 10-15 minutes then came down to an idle without issue to dock. No spit/sputter or rpm weirdness.

Considering it was hard to start, ran fire back home, now won't start, doesn't make me think ECM either, but cannot rule it out yet.
I'm more likely thinking part of the start lock-out circuit that allows the pump and injectors to power up. Most EFI systems lock-out on crank position, oil level, and coolant temp. Those are the 3 sensors I would go after first.

Coolant temp sensor fails high
Oil Level sensor fails low
Crank position just fails and doesn't give feedback.

[HFarr]

When you say you are getting no power to the fuel pump... Are you actually measuring no voltage at the wire feeding the pump itself, or is the pump just not making any noise or running? Forgive me if I missed something earlier.

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[Probably the Killswitch]

When you say you are getting no power to the fuel pump... Are you actually measuring no voltage at the wire feeding the pump itself, or is the pump just not making any noise or running? Forgive me if I missed something earlier.

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I am holding my multimeter leads to the connections on the pump while someone else cranks the key. No voltage at any point.

[SONIC]

Do you have spark?

[secondsupra2004]

I am holding my multimeter leads to the connections on the pump while someone else cranks the key. No voltage at any point.
I have a service/ diagnostic manual for the MEFI 4 system. In it, it states that when the key is first turned on you should have fuel pump run 2 seconds. The ECM sends a signal directly to the fuel pump relay and then after 2 seconds it does not receive an ignition signal it shuts power to the fuel pump relay. I wouldn’t think that coolant temp sensor or oil pressure sensor would be in that initial 2 second circuit.
I would recheck the fuel pump relay fuse and the relay.

[HFarr]

Is there by chance another fuse holder that was added anywhere in the circuit? Really does sound like it would end up being something simple like that by how you described it suddenly not working. Of course I guess a failure in the control module could also just suddenly happen too. Double check to make sure it's not a loose connection or corrosion in a fuse holder prior to it reaching the pump. See if there is voltage on either side.

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[secondsupra2004]

I have a service/ diagnostic manual for the MEFI 4 system. In it, it states that when the key is first turned on you should have fuel pump run 2 seconds. The ECM sends a signal directly to the fuel pump relay and then after 2 seconds it does not receive an ignition signal it shuts power to the fuel pump relay. I wouldn’t think that coolant temp sensor or oil pressure sensor would be in that initial 2 second circuit.
I would recheck the fuel pump relay fuse and the relay.

29795
Here is a copy of the circuit diagram. It should be the same as your boat. There is a procedure for diagnosing, but it requires a scan tool. Maybe the schematic can help you at least trace down the circuit. Hopefully there's nothing wrong with your ECM. Thats where the initial signal to the fuel pump relay originates.

[Holdmybeer]

29795
Here is a copy of the circuit diagram. It should be the same as your boat. There is a procedure for diagnosing, but it requires a scan tool. Maybe the schematic can help you at least trace down the circuit. Hopefully there's nothing wrong with your ECM. Thats where the initial signal to the fuel pump relay originates.

Huge help.

What I see here is the ECM is the ground for the fuel pump relay (Dark Green/White) - Check continuity to ground while turning key to "RUN" position. This would assure that ECM is triggering.

Check Pink wire from fuel pump relay fuse with ignition in "RUN" - should have +12V - if not check fuse or connection at fuse block
If the relay is clicking - should be able to feel this also - when switched to "RUN" then control circuit is good.

Another way to check is to test 87A (unused) on the fuel pump relay - it should have +12V at all times unless the ECM is telling the fuel pump to run. After 2sec, this should go back to having power, if the circuit is working correctly.

Not sure where "FROM SYSTEM RELAY" is providing power, but this could be the problem if no power anywhere in this circuit, and fuses are all good.

I know for certain, that the ECM will be in lockout mode and not start the engine for the other sensors I mentioned earlier, but the initial 2 sec run should function every time the key is switched and the gauges go through the reset process.

[secondsupra2004]

Huge help.

What I see here is the ECM is the ground for the fuel pump relay (Dark Green/White) - Check continuity to ground while turning key to "RUN" position. This would assure that ECM is triggering.

Check Pink wire from fuel pump relay fuse with ignition in "RUN" - should have +12V - if not check fuse or connection at fuse block
If the relay is clicking - should be able to feel this also - when switched to "RUN" then control circuit is good.

Another way to check is to test 87A (unused) on the fuel pump relay - it should have +12V at all times unless the ECM is telling the fuel pump to run. After 2sec, this should go back to having power, if the circuit is working correctly.

Not sure where "FROM SYSTEM RELAY" is providing power, but this could be the problem if no power anywhere in this circuit, and fuses are all good.

I know for certain, that the ECM will be in lockout mode and not start the engine for the other sensors I mentioned earlier, but the initial 2 sec run should function every time the key is switched and the gauges go through the reset process.

Check out this schematic- MEFI relay circuit. I beleive this is the "FROM SYSTEM RELAY" you mentioned.29797

[Probably the Killswitch]

Thank you for the wire schematics- huge help! Unfortunately I did not see these until just now (been down at the boat all day).

I have some developments- not sure exactly what they mean though. Let me know if this makes any sense to you guys:

I removed the fuel pump relay. When I jump the wire from pin 30 to 87 the pump kicks on- so I have good power and ground for the pump itself.

Now this is where things start to get interesting- The multimeter reads 12v on the control side of the circuit (female connectors for pins 85 + 86) when the key is in "run". I removed the two control wires form the connection housing and plugged them directly into the relay, no click and the meter reads 0v.

Can anybody think of a reason why a circuit would drop to 0 volts when connected to a relay (again, the relay itself is fine)? Maybe a bad ground for the ECM? I'm looking for the ECM ground on these diagrams but I'm no electrical engineer. Does anybody know where it is in the physical world?

[secondsupra2004]

Check out a video on YouTube called
“GM FUEL PUMP RELAY TESTING “. It about. 30 minute video and describes in detail the biased voltage produced by the ECM. 12 volts with a test light plugged in to the socket without the relay and 0 volts with the relay plugged in. Check it out.

[Holdmybeer]

Thank you for the wire schematics- huge help! Unfortunately I did not see these until just now (been down at the boat all day).

I have some developments- not sure exactly what they mean though. Let me know if this makes any sense to you guys:

I removed the fuel pump relay. When I jump the wire from pin 30 to 87 the pump kicks on- so I have good power and ground for the pump itself.

Now this is where things start to get interesting- The multimeter reads 12v on the control side of the circuit (female connectors for pins 85 + 86) when the key is in "run". I removed the two control wires form the connection housing and plugged them directly into the relay, no click and the meter reads 0v.



Can anybody think of a reason why a circuit would drop to 0 volts when connected to a relay (again, the relay itself is fine)? Maybe a bad ground for the ECM? I'm looking for the ECM ground on these diagrams but I'm no electrical engineer. Does anybody know where it is in the physical world?

Pin 85 & 86 - are these wires Pink and Dark Green/White?

The Dk Grn/WHT wire is ground. The ECM completes the ground for the circuit. A meter measures voltage differences between the wires. It looks like the relay is shorted and the wires have 12V on both, which is why you are measuring 0v potential difference.

A new ice cube 30A 12V relay is $10. I would try it out and see what happens. You have one in your truck fuse box you could try out and see if it works.

[austin.james07]

Pin 85 & 86 - are these wires Pink and Dark Green/White?

The Dk Grn/WHT wire is ground. The ECM completes the ground for the circuit. A meter measures voltage differences between the wires. It looks like the relay is shorted and the wires have 12V on both, which is why you are measuring 0v potential difference.

A new ice cube 30A 12V relay is $10. I would try it out and see what happens. You have one in your truck fuse box you could try out and see if it works.

Was out today and the boat fired right up and ran fine.... went back to the dock and let it idle for a while and then eventually the boat shut off..... i could not get it started again after that.... I thought I ran the boat out of fuel but that was not the case. The engine is for sure not getting fuel for whatever reason.... I have almost identical systems and this is what I have checked so far....

1. fuel pump power on when bench tested and when I jump the pink to grey wire on the fuse block
2. all (3) blue fuses are good
3. the fuel pump does NOT prime and does NOT get the 2 seconds of power at key on. There is no power running to the fuel pump
4. the relays do not click
5. Waiting to try and swap relays but I did rotate them around as they are all the same and no result was different.

any thoughts here? PLEASE HELP!

[Holdmybeer]

Other things to check:

Engine starting circuit requires the coolant temp switch to be good also. If you lost 1 or both of them, engine will not start.

Oil level is also a sensor that will not allow the boat to start.

Either one of these could have went bad and the reason the fuel pump won't prime.