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Discussion Starter #1
I have two 08 Rancher TRX420FMs. I had to pull the injector out of one and it sat all winter with no injector. I finally decided to get it running when it got warm. I pulled both machines into a garage and put in the new injector. It turned over fine but would not start. Problem was that the fuel pump was not kicking on. For clarity, the machine I will call the "good" machine starts and runs fine. The "bad" machine is the one that sat all winter and now won't start. (Not that it seems germane, but I ran both injectors in the good machine and both are fine.)

I put the bad machine's fuel pump in the good machine. No start, therefore bad fuel pump. Then I put the good machine's fuel pump in the bad machine. No start. Hmmmmm. Both machines have an add-on pull start, therefore two relays. I put the bad machine's relays in the good machine with the good fuel pump. Started fine. So relays are fine.

I know I have a bad fuel pump, but there is something else preventing the fuel pump from kicking on, and it is not the relays. It has a new rectifier, so I don't think it is that. Could it be the PGM-FI unit?
 

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Do you read 12V with your volt meter on the fuel pump when it is supposed to be running? If not, work backwards from there to find out why you are not getting 12V.
 

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Discussion Starter #3
The machine is still in Alaska. I am in the lower 48 for the summer. All this transpired as I was getting ready to leave, so I didn't have a chance to really look into it. I'm obviously not getting 12V, however, because if I was, the good fuel pump would have kicked on. It did not run at all.

I was hoping to buy the parts down here where shipping is quicker and cheaper so that when I go back in the fall, I am ready to get it running right off the bat.
 

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Discussion Starter #4
I will add that the bad machine ran when I parked it. As mentioned, I have two. This one did not start as well when it got colder, so I covered it and ran the other all winter. I was helping a friend with an 07 Rancher sometime in November, and he needed an injector. Rather than wait two weeks for one to arrive, we used the one out of my parked machine (it fixed his.)

I ordered an injector for myself, and waited for a warm day. We had a warm-ish day in about March, so I put my new injector back in and tried to get the machine started. I nearly ran the battery down but no luck. It was pretty snowed in, so I decided to wait for breakup before trying again. When I was finally able to do so, the result was the events described at the start of this thread.
 

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It may be as simple as unplugging every connector and looking for corrosion & plugging them all back in. If you have any china made parts on it anywhere, put OEM parts back on it. You can troubleshoot it quickly by going through the steps in the service manual.
 

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Discussion Starter #6
These are my thoughts.

There are only two possible causes: mechanical failure or electronic failure. Mechanical would be a loose wire or poor connection or some other issue that prevents current from getting to the pump. Electronic would be a failure of a component that produces or routes the current. I think electronic is the most likely because the Honda was running when I parked it. Though it is possible a mechanical failure could have occurred while it was sitting in the cold, my experience has been that these things are pretty hardy. In addition there is the problem of the previously running fuel pump that suddenly died. One possibility could be that a bad component fried the fuel pump, though I don't know if it is possible for that to happen or not. But the suddenly dead fuel pump certainly alludes to more than just a loose wire.

What I was hoping to hear from experts was a little information on how the fuel pump gets its current. What components are key to making a fuel pump operate, and more specifically, which components, if not working properly, would prevent it from doing so? This is the knowledge I do not have, and trying to decode the wiring schematic in my manual makes me dizzy.
 

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I put the bad machine's fuel pump in the good machine. No start, therefore bad fuel pump.
Not necessarily true, thats an assumption. A pump harness or plug problem could explain that. Rotten fuel jelled up in the pump can explain it, frozen water being in it, or a stuck bearing or bad armature can as well. You can put battery power directly to it while the pump is in your hand and see if that pump runs or is stuck.

You said your bike sat outdoors covered all winter. Those kinds of covered conditions can cause condensation & moisture buildup on everything... especially if it is hit by sunlight periodically and the sealed (by deep snow) cover is heated & cooled in cycles. I know all about that problem because I must live with it as well. A lot of my machines are tarped off year round, adding ventilation is the only way I survive those storage methods. Sometimes I lose the game though... and have to fix stuff that went bad or got corroded during storage.

That is why I suggested you take every plug apart on the bike... put eyeballs on them and plug them back in if they are not wet or corroded. Operate every switch relevant to your problem (in this case kill switch, Ign. switch, neutral/reverse/gear selection/indicator switches, etc.) looking for one of them to come back to life if it has been soaking wet & intermittently frozen solid for months. Measure voltages through the fuses themselves by putting a DC volt meter on each contact on top of every fuse. Check the diodes like the starting section of the service manual suggests. It is more likely an electrical failure causing your problem than a mechanical one... and going over everything routinely should reveal it eventually. The service manual shows how to test every switch and function and component on the bike... and you can direct test a few of them yourself once you get them off the bike.

What I was hoping to hear from experts was a little information on how the fuel pump gets its current. What components are key to making a fuel pump operate, and more specifically, which components, if not working properly, would prevent it from doing so? This is the knowledge I do not have, and trying to decode the wiring schematic in my manual makes me dizzy.
Yeah, wiring schematics can do that... LOL. But everything you are asking us for is in the service manual. You don't need to be looking at the wiring diagram just yet... read each section instead.

There are many, many things that can happen to make your bike quit like it did. If I sat here for an hour and listed everything I know about and could think of, I'd still miss half of the answers. This is a guessing game at best... its got to be diagnosed in an orderly fashion once most of the silly stuff is eliminated.

Unfortunately, with the bike sitting alone under a cover 1000s of miles away... its gonna be impossible to diagnose anything from home. At least you are armed with your most valuable resource though, having a printed copy of the FSM handy.

Go through the starting, ignition & fuel injection sections troubleshooting flow charts after you familiarize yourself with operations of each section. Certain things may or may not be mentioned in there... like the display for instance: the display is an integral electronic component for the fuel, ignition & starting circuits on that bike. If it fails, all kinds of bad (or weird) stuff can happen.

If there are any non-OEM electrical parts on the bike, suspect them, cause made in china means made to get your money, then fail. Likewise, if any of the harnesses have been spliced into, altered or fixed, suspect all of those hacks.

Do you have internet access and power in AK where the bike is located? If so, shout us up so we can help you when you get back there. If not, I dunno what to say... this is a guessing game at best, since you don't have the bike handy to work through any diagnostic steps. Hopefully its a silly problem caused by the tarp and not expensive to fix!
 

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Discussion Starter #8
I can finish this post off. A little late, but maybe it will help someone.

One of my wiring harnesses had a connector with a bad "stay put" tab--that bar on the connector end that prevents the connector from backing out of the harness housing. When I plugged the harness in, this one wire would not slide into its slot in the other plug. I held the wire in place with a small screwdriver when I connected the harness and got the two halves to join correctly. I have not had a problem since.
 

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I can finish this post off. A little late, but maybe it will help someone.

One of my wiring harnesses had a connector with a bad "stay put" tab--that bar on the connector end that prevents the connector from backing out of the harness housing. When I plugged the harness in, this one wire would not slide into its slot in the other plug. I held the wire in place with a small screwdriver when I connected the harness and got the two halves to join correctly. I have not had a problem since.
thanks for the update !. small stuff bites us on the butt every time !..lol.
 
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