F150XA Electrical Issues

[slads5874974]

Alright here we go...

YDS and cable will be here tomorrow. I am hoping that it will help reveal my 150's electrical mess.

but until then, this is my problem.

First and foremost. I have no power to the fuel system. I tested the Relay in the fuse box, it's functioning properly. I tested the fuse box per the service manual, everything works there too (relay triggers during the test). But I get nothing when I turn on the main power and switch the key to on position. No VST pump hum, no nothing. The motor is getting plenty of power from the battery bank. Trim works fine etc etc.

I have an old relay that I pulled the cover off of and can manual pinch the relay together (contacts). Once I do that, VST pump hums and I can start the motor. BUT, only #2 and #3 injectors are firing fuel at the intake. Occasionally I will get a pulse of 1 or 4 firing (leading to my misfire issue, see my engine hissing thread).

So this is how I understand the function of the ECU... The ECU controls the pump by grounding a specific wire and closes the connections. Meaning that there has to be 12v getting to the ECU when the key is in the on position (or the power is on), if there is not sufficient power to the ECU, then the ECU doesn't trigger to ground the connection and can not run the pump. So this is also telling that there needs to be enough voltage coming to the ECU to trigger it to ground the pump, through the fuse and closing the relay. And I don't know how to figure out where to test for this voltage???

I have attacked my electrical system with a voltmeter over and over. I can't find the issue anywhere. I have cleaned all of the connections for current and ground wires. I am just missing SOMETHING and I cant figure it out.

Other than hoping that YDS can tell me what the problem is, anyone have some thoughts on this?

Is there a connection from the key box that is preventing power to the ECU (lanyard is good, safety switch is good)?

Could the ECU be shot?

Another note: So When the engine is running (relay closed manually), it randomly misfires (low, mid and high RPMs). I disconnected the injector plugs one-by-one to see which cylinder is misfiring, the end result is that #1 and #4 is not firing at all. how do I know this? because there is no change to the engine running when I disconnect the injectors (Spark Plugs are firing on all cylinders). I did this test on my old F115 and it helped me determine an injector problem.

So this tells me that the fuel system electrical is not telling the injectors to work on 1 and 4.

Soon as I disconnected the 2 or 3, the engine shut down. Not enough to run on one cylinder.


ok... sorry for the long description.

Looking forward to everyone thoughts.

thanks!

[fairdeal]

IMO there is not a good likelihood that YDS will tell solve your problem.

I'm not certain, but I believe on the F150 your yellow ignition power goes to the ECU
which then activates the main relay coil (by grounding it)

the main relay, once closed, supplies power to your fuel pump and injectors (and spark plugs) - which are then are grounded by the ECU to operate.

You say you have checked "all of the connections"...even the ECU pins?

I don't quite follow where you are with the main relay - but I would start with finding out why that is not closing.

FWIW, the pros here have often stated that outright ECU failure is almost unheard of.

[boscoe99]

YDIS is not going to tell anything.

Here is the way that I see it working.
- Battery power to the motor.
- Battery power to the fuse/relay panel.
- Battery power to the PTT relay.
- Battery power to the starter motor solenoid.
- Battery power to the key switch via red wires.
- Battery power to the ECU from the key switch via a yellow wire.
- ECU senses voltage and grounds the main relay to close the relay contacts.
- Relay contacts close and apply voltage to the injectors, the ISC valve, the ignition coils, the fuel pump plus some other components.
- ECU sensing voltage being applied grounds the fuel pump momentarily to build up fuel pressure. If the key switch is turned to the start position the fuel pump will continue to be grounded. If the motor starts and runs the fuel pump will continue to be grounded. If the motor does not run the ECU will terminate the ground to the fuel pump.

If you don't have power (12 volts) to the fuel pump what about power to the rest of the powered components?

[slads5874974]

So I gave it a good try this weekend. Thanks for all the responses! This forum is great. Always good to hear others feedback on how to approach these issues.

Unfortunately, still no progress though. I tested the yellow wire coming from the Key Switch (at the ECU adapter/pin). Full Power there leading to the ECU. But still not activity coming out of the ECU once it receives current from the yellow wire.

I did some more voltmeter testing and noticed that there was a some voltage coming out of the R/Y wires that are typically hot. The Voltage was VERY low. Extremely low actually. So I am not sure if that has anything to do with it, or there is resistance anywhere in the wire harness?

One thing I did notice is two connections in the harness are EXTREMELY corroded and destroyed when I pulled their caps. I attached pictures of the plugs after I had cleaned them (I should have took before and after pictures). Once I cleaned them, it revealed damage and I am feeling that I need to replace the wire harness now just to be safe. Frustrated because its not an easy harness to find (used), and new its over 500$. There are some used harnesses out there, but they are slightly different. The F150's have wire harness variations over the past few years? Not sure if that matters, but I would imagine I MUST to keep the exact same harness. Funny how Yamaha changed the harnesses for the F150s. My harness for the XA model has these two plugs (see attached image, Part 63P-82590-61) and other F150 model's harnesses do not have these end plugs. These two plugs lead to know where, they just capped. However I am certain that they all obviously work with each other observing how they are connected over the mini bus bar of some sort at the ends of the plugs.

https://www.dropbox.com/s/yd7k86xnwp..._0178.JPG?dl=0
https://www.dropbox.com/s/wpgyt1f9mk..._0180.JPG?dl=0
https://www.dropbox.com/s/y66eco90ps..._0176.JPG?dl=0
https://www.dropbox.com/s/lx64mi5qka...%20PM.png?dl=0

So I am stuck at this point. Need to save up a little more money to purchase the harness. Feeling bummed and actually nervous because if the harness is not the answer, then what is? ECU?

BTW, YDS didnt work. No power from the ECU, then obviously no power to the USB firmware and no communication to the CPU. I did manually override the power again by using the Relay with the pinched connectors. Motor turned right over (Cy2,3 running) and the YDS did turn on, but still no results.

Electrical is really frustrating.

[boscoe99]

Photos don't work for me?

Think of electricity as a puzzle gaame that is fun to be solved.

The R/Y wire should have battery voltage (or damn near it) on it at all times. If not, that is a problem that needs to be solved before you can move on to finding and solving other issues. Bad voltage in to a device will result in bad information out of a device. Folks then start thinking the device is bad, when it's not.

Why all of the corrosion do you know?

[rodbolt17]

my guess would be the power distribution hub is corroded.
the misfire on 1&4 is most likely a power loss to an ign coil.
1&4 spark and 2&3 spark together.
it is called a waste spark system.
the injectors only fire in groups at rapid acceleration, other than that they fire in sequence.
about the only thing YDS well TELL you is what the ECU"sees" not what is bad.

[slads5874974]

Not sure why I cant get the images to upload. Here is the links to all the images on my public drop box account.

https://www.dropbox.com/s/0ggpktyspg...%20AM.png?dl=0
https://www.dropbox.com/s/45a2t3jfni..._0177.JPG?dl=0
https://www.dropbox.com/s/y66eco90ps..._0176.JPG?dl=0
https://www.dropbox.com/s/lx64mi5qka...%20PM.png?dl=0

Thanks a lot for all the responses. Really appreciate it. At this point I am think that the new wire harness will really be the best option just to make sure there is nothing I am missing. I don't want to be out on the water and have something go wrong.

[rodbolt17]

I am thinking a visual inspection of the ground and feed hubs is in order.
500+ bucks is a lot of primers,powder brass and bullits.
not to mention rifles or cool refreshing beverages.

I just scored a French MLE 16 carbine for 260 including shipping.
scored an old sears ranger .22 single shot fot about 50.
scored a very pretty model 500 Mossberg with a 28"vent rib barrel for 190 with shipping.

depends on what ya wanna spend your coin on.

[pstephens46]

Those guns hidden in the truck or did you tell the wife?

[panasonic]

Not sure why I cant get the images to upload. Here is the links to all the images on my public drop box account.

https://www.dropbox.com/s/0ggpktyspg...%20AM.png?dl=0
https://www.dropbox.com/s/45a2t3jfni..._0177.JPG?dl=0
https://www.dropbox.com/s/y66eco90ps..._0176.JPG?dl=0
https://www.dropbox.com/s/lx64mi5qka...%20PM.png?dl=0

Thanks a lot for all the responses. Really appreciate it. At this point I am think that the new wire harness will really be the best option just to make sure there is nothing I am missing. I don't want to be out on the water and have something go wrong.

Looked at all your pictures and you have some really bad corrosion in those connectors. One spade is completely corroded away. I don't think you will get any joy from that motor until you replace that harness.IMO

[fairdeal]

Looked at all your pictures and you have some really bad corrosion in those connectors.

the photos are quite surprising:

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[rodbolt17]

and those are the power and ground distribution hubs.

[rodbolt17]

I don't see any tabs missing.
the harness diagram will show which wires are joined together.
now ya gotta make a choice.
repair what you have or bust out 1/2 a boat unit.

[boscoe99]

What do the rest of the electrics look like?

Fuse/relay panel?

Stator?

Starter motor?

How long was the motor under water?

[fairdeal]

How long was the motor under water?

that was my thought also!