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Festus wrote: ↑Sun Apr 24, 2022 7:42 pm See what happens when you celebrate too early? Viper Dad and his son installed his fuel pump replacement motor today. Still surges.

He said he noticed that when they opened the tank, twice (don’t ask), it seemed to release an excessive amount of pressure. That has me questioning if it’s a vent issue.

Not that many moving parts in a tank so it’s odd that switching tanks worked but changing fuel pumps didn’t. Only thing left is the vent, right?

Sorry to hear the disappointing news. If it is a venting issue, and that could be the answer, ViperDad will have a 2021-2022 2013 model. So many new parts installed. I'm sure your tank vents properly, hence the no surging. Tell him this: After he fixes it, I'll buy it from him for a very low fair price. I know he will appreciate that.

It is normal for the tank to pressurize a bit, more than one have had a geyser when it's hot out.... however, one can check the little vent grommet and if need be take the tank cap off and disassemble it for inspection. Someone in another sandbox kindly informed us these are not vents but pressure relief valves..... well, they have to work both ways, air has to replace fuel somehow.
So, in the cap is a little ball that seals things off in the event of a tipover so fuel doesn't run all over the place..... check that it moves freely (and don't lose it, lol).

I don't profess to know if any of this has much to do with surging, but let's hope it's that simple.

I had the geyser experience on my 04 once. After that, i tended to stand to one side opening the cap.

bungie4 wrote: ↑Thu Apr 28, 2022 5:08 pm I had the geyser experience on my 04 once. After that, i tended to stand to one side opening the cap.

You stopped lighting up a fag at the pump as well I’m sure.

wheatonFJR wrote: ↑Thu Apr 28, 2022 5:46 pm

bungie4 wrote: ↑Thu Apr 28, 2022 5:08 pm I had the geyser experience on my 04 once. After that, i tended to stand to one side opening the cap.

You stopped lighting up a fag at the pump as well I’m sure.

Now the only fags he lights up are in the bedroom

Festus wrote: ↑Sun Apr 24, 2022 7:42 pm See what happens when you celebrate too early? Viper Dad and his son installed his fuel pump replacement motor today. Still surges.

He said he noticed that when they opened the tank, twice (don’t ask), it seemed to release an excessive amount of pressure. That has me questioning if it’s a vent issue.

Not that many moving parts in a tank so it’s odd that switching tanks worked but changing fuel pumps didn’t. Only thing left is the vent, right?

Did it release pressure or suck in air when you opened the lid? Suction might suggest that the gas cap ball valve is stuck and the engine could be starving for fuel. Pressure could point to a venting issue but I don't expect it would cause the running problems you are seeing.

Note: If air is not replacing fuel as it is consumed, it is possible for the vacuum generated to collapse a tank...

Have you measured pressure on the fuel rail going to the injectors? (Is the new pump supplying adequate pressure?)

Festus wrote: ↑Fri Apr 08, 2022 8:40 pm Well, those who said fuel pump might have nailed it.

Went by Viper Dad’s this afternoon, swapped tanks and the problem went away!

Pulled his fuel pump and cleaned the filter best we could. Put it back in, he took it for a test ride. He said it was better. So fixed with swapping tanks, better with cleaner filter.

I think he’s got the new pump inners coming.

Hopefully we can put this to rest.

OK, the piece missing if ya wanna try it. Will his tank make your bike surge? How long was the test ride?

Don’t know anything more, he’s a slacker with the lame excuse of something to do with his wife and kids.

blind squirrel wrote: ↑Thu Apr 28, 2022 5:53 pm

wheatonFJR wrote: ↑Thu Apr 28, 2022 5:46 pm

bungie4 wrote: ↑Thu Apr 28, 2022 5:08 pm I had the geyser experience on my 04 once. After that, i tended to stand to one side opening the cap.

You stopped lighting up a fag at the pump as well I’m sure.

Now the only fags he lights up are in the bedroom

https://imgur.com/gallery/CrKFfcZ

Cap open, still surging.

Next?

Festus wrote: ↑Fri Apr 29, 2022 5:54 pm Cap open, still surging.

Next?

Turn it into a parts bike?

Festus wrote: ↑Fri Apr 29, 2022 5:54 pm Cap open, still surging.

Next?

I think you may need to verify with a tank swap again...
If it is OK with the other tank and the open lid shows it isn't a venting issue, then the "fixed" fuel pump is still a problem. Either not producing enough pressure or inlet filter still crappy (did it get changed with the pump?)

If it is still a problem with the other tank (and pump), then:

Examine injector inlet filters for crud.
Check pressure on fuel rail.

Got any photos or diagrams of the injector inlet filters? I'm thinking the next step is to pull off the throttle bodies and do an extensive cleaning, and check those injector filters at the same time. Check the fuel rail pressure as well. Has to be fuel related, I think. Just not that many things left to change or check.

New pump came with a new filter, yes.

blind squirrel wrote: ↑Fri Apr 29, 2022 5:59 pm

Festus wrote: ↑Fri Apr 29, 2022 5:54 pm Cap open, still surging.

Next?

Turn it into a parts bike?

It's an FJR, not a Tenere'

Festus wrote: ↑Fri Apr 29, 2022 6:39 pm Got any photos or diagrams of the injector inlet filters? I'm thinking the next step is to pull off the throttle bodies and do an extensive cleaning, and check those injector filters at the same time. Check the fuel rail pressure as well. Has to be fuel related, I think. Just not that many things left to change or check.

New pump came with a new filter, yes.

Photos courtesy of dcarver.





Inlet filter "baskets" are part of the injector. They might be able to be cleaned by a dip in an ultrasonic tank without taking them out of the injector. Generally can't be removed without ruining them. If you pull the injectors to look at the filters, you might as well get the injectors refurbished. Not terribly expensive and they will be cleaned, filters replaced, flow checked and spray pattern verified.

Edit: If it runs right with the other tank then it ISN'T the fuel injectors...

Festus wrote: ↑Fri Apr 29, 2022 6:40 pm

blind squirrel wrote: ↑Fri Apr 29, 2022 5:59 pm

Festus wrote: ↑Fri Apr 29, 2022 5:54 pm Cap open, still surging.

Next?

Turn it into a parts bike?

It's an FJR, not a Tenere'

I know. A Tenere wouldn't be having this problem.

A sustained test with tank swapped should tell the tale. No sense talking about fuel until that's over. Same issue with the new pump tells me it's leaning against fuel being the issue, but have to prove that out..... was the new pump a complete OEM unit or aftermarket? I may have another suggestion.

blind squirrel wrote: ↑Fri Apr 29, 2022 8:15 pm

Festus wrote: ↑Fri Apr 29, 2022 6:40 pm

blind squirrel wrote: ↑Fri Apr 29, 2022 5:59 pm

Turn it into a parts bike?

It's an FJR, not a Tenere'

I know. A Tenere wouldn't be having this problem.

I’m letting the air out of your tires next time I see you

Ray, it was an aftermarket pump motor only. Those $70 area ones. I don’t have a link but can find out. He took it for an extended ride today, said that it was considerably better but still there.

I would like to pull the throttle bodies and extensively clean them.

Do the tank swap first for an extended run. The TB's aren't causing the surge IMHO. The only crud you'll see is on the butterfly plates and that won't cause surge.

If you want to spend time, rig up a hose fitting to test fuel pump pressure on the hose that feeds the TB's.... just so you're not in too much suspense, the plastic OEM pump body contains the pressure relief valve..... thus I mention the extended test with your tank and you could do vice versa.

Edit add - the thing that doesn't quite make sense is when at a steady 3000-4000 rpm when fuel demand is moderate....