Fuel pump not priming

[Wheaton Jr.]

Kill switch is not on. It will crank and crank, pretty sure it doesn't do that if the switch is engaged.

[rbentnail]

Kill switch is not on. It will crank and crank, pretty sure it doesn't do that if the switch is engaged.

Yep, you're right.

[raYzerman]

Terminology thing... Kill switch in the Run position is ON, with contacts closed to feed power to the Fuel Pump Relay.

[wheatonFJR]

Terminology thing... Kill switch in the Run position is ON, with contacts closed to feed power to the Fuel Pump Relay.

Yes, it is set for bike engine to be on...but kill switch is NOT applied to perform its named function, which is to "kill" the engine.

[Bust]

Yes, it is set for bike engine to be on...but kill switch is NOT applied to perform its named function, which is to "kill" the engine.

Now why the fuq would you want to KILL that engine. Seems like it had been damned good to you all those years you heartless BASTGE!

[Wheaton Jr.]

I was able to take some time to get the pump out today. That part didn't take long at all, just followed the little trick in the video link here. It was very helpful. https://www.youtube.com/watch?v=TsOKmeuJ0_8




The part that took more time was being patient enough to get all the electrical connectors out and take the pump assembly apart without breaking the 20 year old plastic, since the new assembly is over 500 dollars. The fuel filter definitely has some particulates on it, but I wouldn't call it clogged up.




The pump itself appears to have corrosion all around it, and the same stuff is in the tank as well. I don't know if it's rust or not, but it scrapes off pretty easily with a screwdriver. Some of that stuff probably got though the fuel filter though.




I hooked up the battery straight to the pump to eliminate any wiring in the pump housing and it still did nothing. I then took some resistance readings and that's where it gets a little weird to me. I triple checked everything and made sure the meter had good contact with the motor contacts. The first time, the motor read 20 million (not a typo) Ohms, basically an open circuit. I thought, easy enough, the motor is dead, just replace it with a new one. I was able to spin the pump by hand, it didn't seem bound up at all by feel. After that I took another resistance reading, this time about 10 thousand Ohms, still way to high. I spun it by hand one more time, and this time I got it to read 2 Ohms. I don't know what its supposed to read, but I hooked it up to the battery again and it turned on and spun up under power for a split second and then stopped. The next reading was 10 thousand Ohms again. I spun it more by hand and it read 2 Ohms again. I reversed the leads to spin the pump the other way and it ran freely for as long as I had the battery connected, about 10 seconds. I connected the pump the right way to the battery and it spun under power for a good 15 seconds, as long as it was connected, it didn't stop or cut out. I took more resistance readings now and it always shows 1 to 1.5 Ohms, maybe what it's supposed to read.

I know some about DC motors, but am by no means a master of them, there are also a lot of different kinds. The confusing part is that the resistance reading would change as I turned the motor by hand, and then after I got it to run, the high resistance readings went away. I would have thought that the motor coil reading would read the same no matter if I was turning the motor or not. I don't know if you can have a dead spot in the motor coil or something else to cause that, like I said I don't know a ton about DC motors. I am thinking even though I can get the pump to run, to replace it with a new one and just use the old housing. I probably wouldn't trust this one anymore and it's also 20 years old. I'll just have to clean the tank out, get the new o-ring for the pump to seal against the tank, and it should go back together pretty easy. In the end I guess I don't know what caused it to fail, either mechanically bound up or something broken in the electrical motor for the pump. Everything taken apart is pictured below, just replacing the pump seems like a good option. Thanks for the help and ideas on this one.

-Wheaton Jr.

[mcatrophy]

...
I hooked up the battery straight to the pump to eliminate any wiring in the pump housing and it still did nothing. I then took some resistance readings and that's where it gets a little weird to me. I triple checked everything and made sure the meter had good contact with the motor contacts. The first time, the motor read 20 million (not a typo) Ohms, basically an open circuit. I thought, easy enough, the motor is dead, just replace it with a new one. I was able to spin the pump by hand, it didn't seem bound up at all by feel. After that I took another resistance reading, this time about 10 thousand Ohms, still way to high. I spun it by hand one more time, and this time I got it to read 2 Ohms. I don't know what its supposed to read, but I hooked it up to the battery again and it turned on and spun up under power for a split second and then stopped. The next reading was 10 thousand Ohms again. I spun it more by hand and it read 2 Ohms again. I reversed the leads to spin the pump the other way and it ran freely for as long as I had the battery connected, about 10 seconds. I connected the pump the right way to the battery and it spun under power for a good 15 seconds, as long as it was connected, it didn't stop or cut out. I took more resistance readings now and it always shows 1 to 1.5 Ohms, maybe what it's supposed to read.
...

Sounds very much like worn brushes and/or dirty commutator or conceivably one open circuit coil on the rotor.

If the latter, depending where the motor stops, you would get the open circuit (20M Ohms) or 10K-ish.

2 Ohms sounds not unreasonable for a functioning segment.

The motor possibly would run if it can start, inertia would probably get it past the bad segment. This might well be marginal, hence the inconsistent running when it does go.

I have no idea whether you can get to the innards non-distructively.

[wheatonFJR]

I have no idea what David/"Jr" posted, but he sounds schmart...takes after his mom.

[raYzerman]

Excellent work, David. Yep I'd replace the pump.... can't trust that one. Flat spot somewhere.... the pump looks cleaner than I expected, all minor stuff even the accumulated coating on the pump.... see what's coating the inside of the bottom part of the tank.... if there's flaky rust, tank upside down (if fill cap seals), no pump, fill with water/vinegar, let sit for an hour, slosh around and dump it. You could slosh around some isopropanol later and that would take care of any residual water.

[wheatonFJR]

Thanks Ray, et al for the assist.

[FJRoss]

There are a couple of used Gen I fuel pumps on eBay right now but is it worth the risk?
They also have several listings for the motor/pump plus filter (new) for a reasonable cost.
I think I read somewhere about someone just replacing the motor unit...?

Edit: I wouldn't trust the old one at this point. Also, if rust/particulate made it through the pump filter, you might want to check the inlet "baskets" of your injectors. Injectors can be cleaned or refurbished...

[bigjohnsd]

I think you might take that pump to an old-style auto parts store and see if a helpful counterman might be able to replicate it for you. There just aren't that many different Japanese Fuel Injection fuel pumps out there. Worth a try. Any numbers or brand info on the pump/filter assy itself? Searching for those numbers may reveal a source too.

[Cav47]

I have no idea what David/"Jr" posted, but he sounds schmart...takes after his mom.

Postman!

[Cav47]

I have no idea what David/"Jr" posted, but he sounds schmart...takes after his mom.

Except the phenotypes are strong with Sr. and Jr.

Yeah, must be the maternal stock.



(says the guy who has a kid entering med school)

[wheatonFJR]

I have no idea what David/"Jr" posted, but he sounds schmart...takes after his mom.

Except the phenotypes are strong with Sr. and Jr.

Yeah, must be the maternal stock.



(says the guy who has a kid entering med school)

You keep using those big werds and I'm signing out of this thread...

[Hppants]

If it were mine, I'd offer this seller $200.00 shipped, and walk it back a bit to $225.00 if necessary:

https://www.ebay.com/itm/363776466252?f ... Sw9EJiEDAc

I bet the seller will bite. Tell the seller that the fitting on the plastic hose connection assy is broken (even though you likely don't need it).

[Wheaton Jr.]

I ordered a QFS pump that comes with a new fuel filter, wiring harness if needed for $70. Assuming everything goes well, I should have it put back together this weekend and see if she starts.

[raYzerman]

I have replaced a couple of Honda pumps with Quantum or similar, the Honda guys seem to have issues a lot, the same one is used in a shit ton of cars...... I have paid as little as $25....... not much different than the one for Yammy. Anyway, I'm happy to see someone finally replacing just the pump! Kool beans!. Lemme know which part number you picked up....

[dcarver]

If you're not in a hurry, I have a gen 1 tank and pump the FjRay gave me. I can pull the pump and ship to you IF you can wait for end of month. I'm still working 6x12 graveyard at the nookie. You pay shipping, cheapskate.

[wheatonFJR]

If you're not in a hurry, I have a gen 1 tank and pump the FjRay gave me. I can pull the pump and ship to you IF you can wait for end of month. I'm still working 6x12 graveyard at the nookie. You pay shipping, cheapskate.

Carver,
Thanks for the offer, but David told me that he already ordered the part and might be working on it right now actually. I don't know, Louanne and I are visiting #1son and d-in law in San Antonio right now.