Medium Pressure Pump wont come on

[Goosehunter]

The medium pressure pump on my VZ250TLR works intermitently. I have checked the continuity of the blue wire which is good, and it has 12v on the red/yellow at key on. I have also checked the kill switch in my YDS and it indicates it is not activated there. I have also pulled the lanyard and tested it by cranking the motor and get the audible alarm.

I replaced the fuel pump relay which didn't help. What else would prevent the pump from coming on. The pump does work if I jump the blue wire directly to ground.

I'm also curious if anyone can tell me what turns that pump off when it works normally after the 5 seconds from key on. Is there a pressure sensor telling the ECU to open the ground path on that fuel pump blue wire after those 5 seconds?

[Goosehunter]

Anyone????

[rodbolt17]

the ECU controls it at key on.
then based on pulser coil inputs the ECU controls it while the engine is running.

[Goosehunter]

the ECU controls it at key on.
then based on pulser coil inputs the ECU controls it while the engine is running.

Thanks, I knew the ECU controls the ground path through the Blue wire. Which I have no ground path at present.

[boscoe99]

the ECU controls it at key on.
then based on pulser coil inputs the ECU controls it while the engine is running.

Does the same blue wire that is grounded by the ECU to operate the fuel pump also apply the ground for the electric oil pump?

Damn Yamaha electrical wiring diagrams.

[rodbolt17]

no.
the blue wire for the oil pump is separate, the oil pump doesn't work below about 1500 RPM.

[boscoe99]

no.
the blue wire for the oil pump is separate, the oil pump doesn't work below about 1500 RPM.

I see what appears to be a blue wire from the oil pump to the relay.

Here is the source of my confusion. It appears that Yamaha is defying conventional Yamaha methodology and is using a yellow wire as the ground wire to close the relay. The relay closing then applies the ground to the fuel pump via a blue wire.

With all of the wire colors that are available it seems very strange for Yamaha to do this. Why not a purple or any other color wire?

Do you agree or disagree?

[rodbolt17]

dunno other than some of the Yamaha diagrams tend to suck, almost as bad as the diagram for a Volvo 300ec.

[boscoe99]

The medium pressure pump on my VZ250TLR works intermitently. I have checked the continuity of the blue wire which is good, and it has 12v on the red/yellow at key on. I have also checked the kill switch in my YDS and it indicates it is not activated there. I have also pulled the lanyard and tested it by cranking the motor and get the audible alarm.

I replaced the fuel pump relay which didn't help. What else would prevent the pump from coming on. The pump does work if I jump the blue wire directly to ground.

I'm also curious if anyone can tell me what turns that pump off when it works normally after the 5 seconds from key on. Is there a pressure sensor telling the ECU to open the ground path on that fuel pump blue wire after those 5 seconds?

If you look at the Yamaha drawing I provided it appears (to me anyway) that the yellow wire from the relay to the ECU is grounded by the ECU to close the fuel pump relay. Which in turn provides the ground to the fuel pump via the blue wire. You might want to check that yellow wire.

Also, with the connector disconnected from the ECU, and with the key turned on, how about checking the pin for the yellow wire first for the presence of any voltage? Second, maybe do a continuity check to verify that the yellow wire does in fact run from the ECU to the relay. If so, maybe ground that yellow wire to see if it in fact closes the relay.

[Goosehunter]

If you look at the Yamaha drawing I provided it appears (to me anyway) that the yellow wire from the relay to the ECU is grounded by the ECU to close the fuel pump relay. Which in turn provides the ground to the fuel pump via the blue wire. You might want to check that yellow wire.

Also, with the connector disconnected from the ECU, and with the key turned on, how about checking the pin for the yellow wire first for the presence of any voltage? Second, maybe do a continuity check to verify that the yellow wire does in fact run from the ECU to the relay. If so, maybe ground that yellow wire to see if it in fact closes the relay.

Boscoe, thanks I'll try that. This problem is intermittent which is really frustrating. I tested the pump before I left the driveway the other day, worked fine. Got to the lake 2hrs away, and murphy said nope it aint gonna work. Did that to me three times last week.

I have about half tank of fuel in this boat I need to burn so I can fill it and winterize the boat. Looks like I'll be pumping it to cans instead and then dumping it. Then fresh fill the boat and stabilize it. That half tank of fuel is from a fill 4 months ago so don't think just sweeting it up is a good idea. It is ethanol free gas too. Hate to waste it but I don't know what yamalube ringfree will do to a car, but I ain't gonna find out.

[boscoe99]

Ring Free won't harm a car motor at all. In fact, many Yamaha people run it in their automobiles as a normal course of business. Don't dump the gas. Just use it up in the car.

[Goosehunter]

Ring Free won't harm a car motor at all. In fact, many Yamaha people run it in their automobiles as a normal course of business. Don't dump the gas. Just use it up in the car.

Ok, thanks. That would make me feel better.

Something I have been wondering about is the oil injection system having anything at all to do with the fuel pump ground not closing. My boat has a ugly history. Stolen motor, hull replaced, etc. I bring this up because when the motor was replaced after original was stolen the harness from the motor had to be replaced. Then when the hull was replaced it was a bastardized job, broken fishing rods in the lockers, transducer wires pinched by top cap. Just a real mess and shit job.

Now fast forward to today. I checked the harness plug for the harness going to the boat. I found moving it around seemed to generate the problem. So, I don't know if the yellow wire is pinched somewhere under the top cap. I need to go trace and do some continuity checks. I also found the plug for the oil level warning indicator at the engine is not plugged in to anything going to the boat. There has been a wire spliced in to the pink wire on that plub and it does go up in to the boat. I need to go trace it. One thing, when this problem surfaces it always seems to be around the time I add oil to the remote tank.

[boscoe99]

Ok, thanks. That would make me feel better.

Something I have been wondering about is the oil injection system having anything at all to do with the fuel pump ground not closing. My boat has a ugly history. Stolen motor, hull replaced, etc. I bring this up because when the motor was replaced after original was stolen the harness from the motor had to be replaced. Then when the hull was replaced it was a bastardized job, broken fishing rods in the lockers, transducer wires pinched by top cap. Just a real mess and shit job.

Now fast forward to today. I checked the harness plug for the harness going to the boat. I found moving it around seemed to generate the problem. So, I don't know if the yellow wire is pinched somewhere under the top cap. I need to go trace and do some continuity checks. I also found the plug for the oil level warning indicator at the engine is not plugged in to anything going to the boat. There has been a wire spliced in to the pink wire on that plub and it does go up in to the boat. I need to go trace it. One thing, when this problem surfaces it always seems to be around the time I add oil to the remote tank.

I don't see any connection between the oil transfer system not working and the fuel pump working intermittently. They do share the same source of electrical power however.

For the motor to run correctly all it needs from the boat is battery power, battery ground and voltage from the key switch. The sensor switch on the engine mounted main oil tank does not go to the boat. It goes to the engine's computer. Now there is some stuff that runs from the motor to the remote oil tank that is in the boat.

Are you going to be able to check the continuity of some wires and voltages on some wires for us? Have you independently tested the relay itself outside of the boat to see if it works correctly each and every time it is energized?

[Goosehunter]

I don't see any connection between the oil transfer system not working and the fuel pump working intermittently. They do share the same source of electrical power however.

For the motor to run correctly all it needs from the boat is battery power, battery ground and voltage from the key switch. The sensor switch on the engine mounted main oil tank does not go to the boat. It goes to the engine's computer. Now there is some stuff that runs from the motor to the remote oil tank that is in the boat.

Are you going to be able to check the continuity of some wires and voltages on some wires for us? Have you independently tested the relay itself outside of the boat to see if it works correctly each and every time it is energized?

Yes I can take readings for the forums review. The plug I referred to as being unplugged and having a wire spliced to its pink wire is the oil sensor level warning indicator plug. It is in the service manual in the schematic on the page proceeding the drawing you copied from above in one of your posts. It is down in the lower right of that drawing. It has a spliced wire running up in to the boat up under the gunnel going to the operator station somewhere. I have measured continuity on the plug and at the engine for the remote oil tank located in the boat. All four of its wires are good continuity wise.

The installed fuel pump relay is brand new, and I still have the old one. The problem presented with the old relay installed and remains with the new one. I can check both outside the boat. I just need to know what to check. I assume the proceedure in the service manual for testing it is what you suggest?

[boscoe99]

Yes I can take readings for the forums review. The plug I referred to as being unplugged and having a wire spliced to its pink wire is the oil sensor level warning indicator plug. It is in the service manual in the schematic on the page proceeding the drawing you copied from above in one of your posts. It is down in the lower right of that drawing. It has a spliced wire running up in to the boat up under the gunnel going to the operator station somewhere. I have measured continuity on the plug and at the engine for the remote oil tank located in the boat. All four of its wires are good continuity wise.

The installed fuel pump relay is brand new, and I still have the old one. The problem presented with the old relay installed and remains with the new one. I can check both outside the boat. I just need to know what to check. I assume the proceedure in the service manual for testing it is what you suggest?

Do you have the service manual? The relay test procedure is in there. I can provide a copy of the procedure if needed. Unfortunately the SM provides nothing at all about checking continuity of wires from point to point.