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gold-n-rod
08-29-2008, 12:58 PM
When the battery is on, I get an electrical/pump noise that won't stop until the battery is turned off.

This I know:

The boat runs just fine.
It's not the bilge blower.
It's not the trim pump.
It's not the tab pump.
The bilge pump operates correctly via float switch and dash switch.
There are 2 wires, each holding 10 amp fuses that run to the battery switch; pulling these fuses does not stop the noise.

Accessing the bilge pump to troubleshoot is not possible. Freaking Donzi put it under the oil pan up front and only someone with 4' monkey arms could get in there. I'm already bleeding like hell from even trying.

Any thoughts? I'd be happy just pulling a fuse to isolate/ID the problem. I don't feel comfortable using the boat knowing something is running that shouldn't.

Good thing I have 2 boats!!!!!!!!

Donziweasel
08-29-2008, 01:07 PM
Do you have an electric fuel pump?

ky-donzi
08-29-2008, 01:12 PM
Could it be the fuel pump. Mine runs for quite a while before it shuts off, but only when I turn the key on


does it do it with the in the key off position.. You say battery on, is that what you meant?

Oh one other thing,, I know you say it's not the tabs, but Mine retract automaticly when I shut the key off. could it be that the limit switch is bad on that... and the pump is running and just recyclin fulid

DonziJon
08-29-2008, 01:13 PM
Maybe the Radio/Stereo/CD Player is ON, and tuned to a NON Station at low volume. OR: More specific: Maybe the CD player is spinning....with or without a Disc. I have a home CD player that sometimes spins up when trying to Open the CD drawer .. even when the drawer is empty.... and during this episode, the drawer won't open without some external help. Can't think of anything else. John

justleft
08-29-2008, 03:02 PM
You can put a hose into the bilge and turn on the water.

That will tell you if it's the bilge pump. Could be a piece of
krud sticking the float switch up.

I just tested mine after a friends boat went down because of
a broken bilge pump hose.

chappy
08-29-2008, 04:29 PM
Could be a piece of
krud sticking the float switch up.

This drained my battery once. Sprayed it lightly, very lightly, with a garden hose to get the chit out.

gold-n-rod
08-29-2008, 04:43 PM
The pump comes on, via the float, when the bilge is filled with water. It also comes on when the dash switch is activated. With water in the bilge, the "noise in question" does not result in any water being pumped! :confused::confused::confused:

And yes, it has an electric fuel pump since it's EFI. Anyone know where said fuel pump is located and how is on/off determined???

Donziweasel
08-29-2008, 04:59 PM
Most fuel pumps for EFI kick on when you turn the key, not on, just one position. They then pressurize the system until the correct pressure is reached. Then the shut off until a pressure drop (IE: starting the engine). Perhaps the pump isn't turning off when system pressurized. I have no idea where it would be on your boat.

ky-donzi
08-29-2008, 05:05 PM
What engine do you have? I have a 5.7 MPI and it is located on the port side of the engine at the bottom. The fuel pump looks like a long barrel with some cooling hoses going to it, along with fuel hoses. I bet this is what you heard

mrfixxall
08-29-2008, 05:34 PM
Fuel pump reley could be stuck keping the fuel pump running? or mabe? do you have a amp for the stero with a cooling fan built into it thats making the noise..

gold-n-rod
08-29-2008, 06:45 PM
UPDATE!!! It's definately the fuel pump. One can hold their hand on the line running to the fuel rail and feel that it's pumping.

As others have mentioned, the pump is supposed to come on when the key is turned, build up pressure and then shut off.

Is there a regulator or pressure limit switch/sensor that's gone bad? What's odd is that it energizes when the battery is switched on as opposed to the ignition. Bad ignition switch? I tried to rule that out by removing the red wire from the ignition switch and then turning on the battery...... no change. :(

Thanks for all the great ideas, keep 'em coming.

mrfixxall
08-29-2008, 06:58 PM
UPDATE!!! It's definately the fuel pump. One can hold their hand on the line running to the fuel rail and feel that it's pumping.
As others have mentioned, the pump is supposed to come on when the key is turned, build up pressure and then shut off.
Is there a regulator or pressure limit switch/sensor that's gone bad? What's odd is that it energizes when the battery is switched on as opposed to the ignition. Bad ignition switch? I tried to rule that out by removing the red wire from the ignition switch and then turning on the battery...... no change. :(
Thanks for all the great ideas, keep 'em coming.

pull the relay and see if it turns off,may be stuck on..it should run for 5 second to prime the fuel rail then shut off which is done through the pcm.either its the pcm commanding it to stay on of the relay is stuck on..

I think its in the black box next to the pcm..

http://www.marinemechanic.com/site/page264.html

Donziweasel
08-29-2008, 07:56 PM
Yeah me!:wink: First time I actually diagnosed something before someone else.

Gold-n-rod, glad you found it.:) I bet it was driving you crazy.

gold-n-rod
08-29-2008, 09:24 PM
Yeah me!:wink: First time I actually diagnosed something before someone else.
Gold-n-rod, glad you found it.:) I bet it was driving you crazy.

It's still driving me crazy. It's not fixed, I just know what's making the noise.

I'm wondering if I should disconnect both the red and purple wires at the key switch to be sure to rule it out. There is NO reason why the pump should be energizing withOUT the key on.

Mr. Fixall- thanks for the diagram, but I'm still clueless on where to find the fuel pump relay.... hell, I can't even find the black box. The big block diagram you linked me to doesn't help me much.

MOP
08-29-2008, 09:36 PM
Listen to Mr. F!!! Several items have power to their relays/solenoids etc and are only energized/actuated by the key switch!!!!!!

ky-donzi
08-29-2008, 10:28 PM
See if this makes sense

your relay will have a full time hot into it ......and a switched hot out to the pump (switches on and off) . It also has a ground wire and a signal wire. Most relays have 4 wire and are arranged this way. Your realy is stuck in the on position reguardless of what the key is doing.

On my boat on the port side top beside the exhaust mainfold there is a large black box with a flip lid. this box is approx 12" long and 5" wide. Inside you will find the relays along with the ecm and other controlls. The relay should be about the side of golf ball but square in shape. There are probably 2-4 relay in that box so you will have to trace wires.

Hope that helps

mrfixxall
08-29-2008, 11:35 PM
I know that was a 502 wiring diagram:) most of the new merc stuff hac the same color codes for the relays and controls..

follow the main engine harness to the thickest point of wires,it should take you to the ecm (pcm) look for a kinda water proof box...

before you try to find the relay turn the power switch on and wait about 15 min,this will warm up the relay so you know which one it on and running the fuel pump..when you find the relay unplug it and see if the fuel pump shuts off..if it does now get your dvom and prob the socket the relay plugs into.one should have a constant power supply,one should be switched from the pcm when the ignition is turned on,one is a ground,and the last one supplys power to the fuel pump..if you have two of the wires with power going to them with the ignition off then either theirs a short in the pcm or mabe the alternator took a crap and is feeding power throug the system some where or their could be a bad resistor in the harness (doutful tho) and the repay is ok..if not replace the relay..most auto parts stores carry a 30 or 40 amp relays,their usually around 5 bucks..

somtimes a tap on the top of the relay will unstick it but you should replace it and it will happen again..

MOP
08-30-2008, 07:31 AM
Posts like this and others only grow my passionate love of carbs, I am some glad I am as old as I am. I doubt the governing bodies will outlaw carbs before I am dust!

Donziweasel
08-30-2008, 08:17 AM
oooops...

gold-n-rod
08-30-2008, 11:00 AM
I know that was a 502 wiring diagram:) most of the new merc stuff hac the same color codes for the relays and controls..
follow the main engine harness to the thickest point of wires,it should take you to the ecm (pcm) look for a kinda water proof box...
before you try to find the relay turn the power switch on and wait about 15 min,this will warm up the relay so you know which one it on and running the fuel pump..when you find the relay unplug it and see if the fuel pump shuts off..if it does now get your dvom and prob the socket the relay plugs into.one should have a constant power supply,one should be switched from the pcm when the ignition is turned on,one is a ground,and the last one supplys power to the fuel pump..if you have two of the wires with power going to them with the ignition off then either theirs a short in the pcm or mabe the alternator took a crap and is feeding power throug the system some where or their could be a bad resistor in the harness (doutful tho) and the repay is ok..if not replace the relay..most auto parts stores carry a 30 or 40 amp relays,their usually around 5 bucks..
somtimes a tap on the top of the relay will unstick it but you should replace it and it will happen again..

Problem solved. Thanks, Mr. Fixxall!!!!!!!!!!!!!!!!!!

I found 2 resistors. I took one off and then turned the battery back on....... no pump. Then, I tapped on it, reinstalled it, and the pump stays off until the key is turned. Then, all is normal.

Thanks to everyone who helped me out!!!!!!!!!!!!!

Mr. Fixxall is 'da man!!!!! :angel: