Electric Oil Pump Test Proceedure

[Hunter#1]

I have a VZ250 HPDI that I have been experiencing intermittent medium pressure fuel pump issues with. The VST electric fuel pump shares a common blue wire at the ECU plug with the electric fuel pump relay, and the electric solenoid lube oil pump. Yesterday I was checking continuity of my electric fuel pump's blue wire on the ECU plug and it's connection on the VST tank and it has continuity, that is until you disconnect the two pin electrical connector on the lube oil pump and test it's blue wire continuity. That blue wire has continuity, but as stated I lose it on the electric fuel pump. Now when I plug the electric oil pump connector back in the continuity returns on the electric fuel pump blue wire. The same thing happens with the electric fuel pump relay when connecting and disconnecting the electric oil pump connector.

When I quit yesterday and had everything back together the fuel pump was kicking on. By this morning it no longer worked. I left to do errands and now two hours later it works again. I decided to test the electric lube oil pump per my service manual while the engine is cooperating and starting. The service manual states remove the oil line from the VST tank and start the motor and check for oil discharge. The service manual suggests there should be an oil discharge, but it has none. I checked the red/yellow wire in the connector for that oil pump and it has 12V. The blue wire has no ground.

In a post two weeks ago Rod stated that pump would be off at idle which would explain my results from today i.e. no ground on oil pump blue wire. See post #2 http://www.yamahaoutboardparts.com/f...s-th25074.html

It seems based on my continuity tests from yesterday that when that electric lube oil pump has continuity on the blue wire I will lose it on my electric fuel pump's blue wire. I'm not sure if that is what is suppose to happen or not, but thats what happens in my case. Don't know what the fix is, or if there is even one required. Pretty frustrated here. Motor is running at moment, probably wont be again in a couple hours from now though. Wondering if I have a bad electric oil pump, or possibly a bad ECU.

[rodbolt17]

I am still thinking you have some corrosion in the harnesss/connectors someplace.
both pumps are supplied 12V+ at key on.
both use a blue wire to the ECU and the ECU makes the ground path connection.
as the electric oil pump only runs above about 1500 RPM yet the electric FUEL pump runs anytime the motor is running its a dead give away that they DO NOT share a common ground path.

[Hunter#1]

I am still thinking you have some corrosion in the harnesss/connectors someplace.
both pumps are supplied 12V+ at key on.
both use a blue wire to the ECU and the ECU makes the ground path connection.
as the electric oil pump only runs above about 1500 RPM yet the electric FUEL pump runs anytime the motor is running its a dead give away that they DO NOT share a common ground path.

Rod - Thanks for answering the post. On page 8-34 of my Yamaha service manual there is a proceedure for testing the electric lube oil pump at idle. It is basically disconnect the pumps discharge tube from the VST tank and check for flow. If none replace pump.

When I checked the continuity of the electric fuel pump I have continuity until I disconnect the electrical connection from the electric oil pump. When I reconnect the continuity returns to the electric fuel pump. I am testing at pin hole 55 of the ECU harness plug. The electric fuel pump, the fuel pump relay, and electric oil pump all register continuity at that pin hole. Not sure what is going on or if that is right, but that is what I have.

I am finding after this thing sits overnight that electric fuel pump wont come on at key on, but will later once the ambient temp warms up. I was thinking condensation but this morning there is none. I am really wondering if that ECU is going bad. Is there somewhere it can be sent for testing, much like the PCM on a car. Those can be tested, flashed etc. I would think someone can do same for an ECU on a high performance outboard.

[boscoe99]

--------------

[Hunter#1]

Boscoe - yes I have been using the drawing from the service manual. I also really appreciate your having taken the time to decode and a markup of it. That's above and beyond, thank you.

On the connector when removed from my ECU there are two solid blue wires. One is at hole 55 and the other at 57. When measuring continuity of the blue wire of the electric fuel pump, the electric fuel pump relay, or the electric oil pump I only get continuity on any of them at hole 55. Maybe the wire at 57 is the problem?

[boscoe99]

------------

[Hunter#1]

I noticed that too. But on my motor there is a blue wire there. Maybe faded or I'm color blind. I'm not near the motor but will look again when I get back home this afternoon. Regardless though, if I'm not getting a ground in the fuel pump at key on is there nothing coming from ECU to relay via that yellow wire? Any ideas what to check? That relay is brand new.

[boscoe99]

---------------

[Hunter#1]

What is the complete model of your motor?

Yamaha made some design changes in the 2005/2006 time frame but failed to update the SM. No surprise there.

Boscoe, first I am really appreciating your help. You have no idea how frustrated I have become with this thing. When I left the house at 8:15am this morning the electric fuel pump would not come on at key on. It did last night when I quit for the day. I returned home at this morning at 11:30am (ten minutes ago) and it now works again. Double ugh.

Anyway I have a VZ250TLR manufactured in 06/06. The serial number is 60X L 1004078

Edit: Boscoe one thing I noticed which I haven't mentioned yet since it didn't seem relevant until now. I have YDS, and a few times when I have been experiencing this no electric fuel pump on issue my YDS software was getting the unable to communicate error. That would substantiate the therory of a possible failing ECU would it not?

[boscoe99]

-----------

[Hunter#1]

Your serial number is after the production change. Command Link was introduced and your motor has it. I suspect the blue wire you are referring to is the one that runs to the Command Link connector. Try it and see. The Command Link connector is a four pin type but has only two wires to it. One blue and one white. Might be a cap on the connector if CL is not being used.

Do a test for us please. See if the pin to the R/Y wire at the fuel pump relay has 12 volts when the key is on please. Turn the key off and then see if the Y wire at the fuel pump relay has 12 volts to it for just a few seconds when the key is first turned on.

Can you imagine a company making design changes but then not updating the service manual?

I'll post results here in a few. Need to help wife quick with something. Did you notice my edit above about YDS com failure? Also what is CL? Ineed a better idea of what I am hunting for.

[Hunter#1]

Your serial number is after the production change. Command Link was introduced and your motor has it. I suspect the blue wire you are referring to is the one that runs to the Command Link connector. Try it and see. The Command Link connector is a four pin type but has only two wires to it. One blue and one white. Might be a cap on the connector if CL is not being used.

Do a test for us please. See if the pin to the R/Y wire at the fuel pump relay has 12 volts when the key is on please. Turn the key off and then see if the Y wire at the fuel pump relay has 12 volts to it for just a few seconds when the key is first turned on.

Can you imagine a company making design changes but then not updating the service manual?

These tests at the fuel pump relay, are they on the pin connectors with the relay removed?

[boscoe99]

------------

[Hunter#1]

Yes, check the pins on the wire harness side with the relay disconnected. I am just trying to validate my theory that the relay control circuit side gets power via the R/Y wire with the key on.

Correction please - Check the Yellow wire for ground when the key is first turned on (not 12 volts). I mispoke.

Ok, I'm going out to remove the interference to the relay. Question, on that pin for the yellow wire....how am I going to test that for ground. I mean hook what to what and set what to what on the digital meter.

Also, that electric fuel pump is coming on right now. Just wanted to be sure you saw I had posted that earlier when I got back to my house.

[boscoe99]

First, check the yellow wire for voltage. I don't think there will be any.

Then, set the meter on the continuity scale with one probe to the engine block and one probe to the yellow wire. Turn the key on and see if the yellow wire is one and the same as the block ground.

Yellow is normally key on power. In this case I don't think that it is.