Engine won't start - fuel pump suspected

[jchrisk]

Hi,

I'm a new guy, looking for help. I have a 2005 with low mileage, and the engine wont start. The problem began with a working engine (was on a ride last weekend), but was having idle problems and rough running when cool. Before doing anything else, I opted to change the plugs. It was past time to change them, and easy. But when I lifted the tank, I saw a fuel leak from the return nozzle of the fuel pump. It wasn't running fuel, but I could wiggle the piece, and each time fuel came out slowly. I replaced the o-ring (long process that I'll skip), and that stopped the leak. I also changed the plugs.

However, when I re-installed the fuel pump, the engine won't run. I have a new battery and the engine cranks. The engine fires, but runs rough for a few seconds (usually 2 seconds, sometimes 10) and stalls. I can hear the fuel pump prime when I turn the key to 'on' (all the same sounds I'm used to). I pulled the hose from the engine end, and watched the fuel flow.

Here's the part that I'm unsure of. I've read that fuel should not drain from the tank fuel line when the key is off (at least not after a few seconds when the fuel in the line finishes draining). That is not what I see. When I disconnect the line, fuel continuously drains, albeit at a slow trickle. When I turn the key on, the pump primes and a large flow of fuel begins, then reduces to the trickle after a few seconds.

Does anyone know if this is operating correctly?

Any help would be greatly appreciated.

 

[RossKean]

Fuel pump problems are rare with the FJR. Something to check is the condition of your tank! If it is rusty (or dirty), the inlet screen on your tank can get plugged and you will get symptoms as you describe. Initial surge of fuel and trickle. There was an extreme case of this some time ago - I'll see if I can find it.

Edit:

https://www.fjrforum.com/forum//index.php/topic/114439-plugged-fuel-filter/page-1?hl= rust pump

There were some pictures but I can't find them.

A link to RadioHowie's pictures

https://www.halllakeland.com/rex/fjr/pump.htm

Edit again:

If you check the tank condition and there is any evidence of crap, you may want to have a look at the fuel injectors while you're at it. Crud that makes it past the inlet filter on the pump can plug injectors. FJR does not have a separate fuel filter.

 

[jchrisk]

Thanks for the help and related info, RossKean. That's a nasty looking pump!

When I had the pump out of the tank and disassembled, I got a good look at both. The tank interior looks clean, and the pump is completely clear of any debris. When the fuel flows out of the pump, it is also completely clear. My attention on the pump as the issue is due to the fact that I recently had it disassembled, I read that there shouldn't be any flow when the key is off (I have some), and that the engine is firing and running before it stalls out.

If the pump operation sounds normal (with the small amount of fuel flow when turned off), I'll start looking elsewhere.

 

[RossKean]

The question is, of course, was the pump and associated plumbing put back together correctly?? I can't help with respect to "normal" pump behavior since I have never had mine apart and mine is a Gen II (2007). I assume there is no chance that a hose is being crimped? As I mentioned, fuel pump failures are very uncommon on FJRs.

The only other thing you messed with was the spark plugs? Make sure that the caps are firmly seated on the plugs. Hopefully the wires are still making good contact with the connectors in the caps. If you want, you can UNSCREW the caps from the wires, trim 1/4" off the end of the wire and screw the caps back onto the wires. (The caps have a sharp threaded contact spike that actually screws into the wire.) If you try this, don't trim more than necessary - Yamaha does not provide much excess wire!

 

[jchrisk]

I finally had a chance to take a look at the spark plugs. I pulled each one in turn; I first pulled the cap off and inserted a spare plug. I cranked the engine and looked for a good spark. Then I pulled the installed plug out of the engine, cleaned, checked the spacing and re-installed. I made sure each cap had a good, strong fitting over the plug when re-installed. All four wires produced a good spark (on one I had to trim a bit of the wire back at the cap first - it looked a bit corroded). The plugs themselves were a bit wet with a black film; it cleaned up easily with a rag before re-installing. I don't know if that is from flooding - I certainly have cranked the engine enough that its going to flood, or if it indicates a bigger problem. Surprised it was dark.

All that done, cranked the engine with WOT. Still same exact problem.

A couple other notes: It would never fire up with WOT. But it did when I let go of the throttle into normal position and cranked it. On a few occasions, it would fire up and run smoothly for 10 seconds at 2k RPM. Then stall. Each time, if I applied any throttle whatsoever, it would stall immediately.

I'm at a loss. Seems like a fuel starvation problem (the stalling after a smooth run of 5 - 10 seconds), though pump seems to be providing a clean feed of gas. The TPS seems okay in diagnostic mode (clean readings from 17 - 100 as I rotated the throttle), if that means anything.

Any thoughts on next step? (like, take it to the shop )

 

[Ignacio]

Then stall. Each time, if I applied any throttle whatsoever, it would stall immediately.

With as much as you've been tinkering I doubt this is likely, but possibly a crimped vent line on the fuel tank and it's in partial vacuum? If you open the fuel tank is there a sudden sucking sound? Or, if you run the engine with the cap open is it the same thing in WOT?

The other thing I could think of when you plugged the fuel lines back in--was there a good positive click when you put the fuel line back on from the bike to the pump? Or did it seem to go back together, you could put the retaining clip on, but never really sure there was a solid connection...so maybe there's just a trickle of fuel making it to the fuel rail.

 

[TownsendsFJR1300]

Sounds like the pump is only working /pressurizing at initial key on...

Remove the air filter, put some fuel in a spray container and spray just a LITTLE into the TB's to see if it'll keep running.

If it keeps running, you know it's the fuel system. I suspect it is.

When the fuel line is removed from the fuel pump, yes, the fitting should NOT leak. (a little from inside the hose will be present of course).

I don't remember if there's a schrader valve on the injector side of the system. If so, monitor that and see what pressure your getting.(If any).

As a side note, there was a large connector (maybe 8-10 wires-forgot), under the fuel tank that was prone to water intrusion.

I had water intrusion as well, which caused crappy running issues. Once the connector was found and opened, it was quite corroded and green. Once cleaned out, dielectric grease applied, the issue was fixed. Worth looking at in any event..

 

[jchrisk]

Ignacio - Thanks. I know the 'click' you're speaking of. Definitely got it when re-attaching the hose at both ends. I'll give the open fuel tank a try when I can, that's an easy one to try but I think I need my second key for it It's around somewhere.

Townsends, thanks for the additional thoughts. That sounds concerning if the fuel line should not be running when the key is off. I might end up having to take the pump back out and check that I got it put back together correctly. That was not fun the first time. But first I'll give the other ideas a try.

Well, when the thunderstorms quit.

 

[jchrisk]

Back to it.

I tried running the engine while the gas tank was open, but no joy.

No corrosion found in any of the wire connectors, either.

I removed the air filter and used a spray bottle to squirt a small amount of gas into the intake while cranking. That worked, to a degree. I could keep the engine running indefinitely with a regular squirts of gas from the bottle - just enough to keep it running at idle. It ran a little choppy from time to time, but it ran. Curious: when I also gave it a little throttle (while maintaining the squirts from the bottle into the intake), the engine would run REALLY rough. Not enough to stall, but the engine did NOT like it at all.

At this point, I think there is a problem with the fuel pump (if for no other reason than it does NOT stop flowing fuel when the key is off). But I'm not sure the pump explains all the symptoms I'm seeing.

I'll need to take the pump out and check it, but that will keep me from running other tests for a tiem. Anyone have any other thoughts before I get started on that?

 

[RossKean]

Check the inlet screens on your fuel injectors. It would be good if you could test the fuel pressure on the rail. If that isn't up to snuff, it's an issue with the fuel pump or a restriction in a fuel line or fitting.

 

[jchrisk]

Quick side question: why would my atmospheric pressure sensor read 100 in diagnostic mode (d02)? It's currently 762.8 mmHg here.

 

[David Morrow]

Any chance that you got any of the spark plug wires connected to the wrong plugs ?

 

[jchrisk]

David - you had me thinking, but no, the wires are attached to the right plugs.

Re: checking the fuel pressure on the rail: does this have to be done with the Yamaha gauge and adapter? I'm not crazy about spending the ~ $270. Anyone checked the fuel pressure with your standard (auto) fuel gauge?

 

[TownsendsFJR1300]

Re: checking the fuel pressure on the rail: does this have to be done with the Yamaha gauge and adapter? I'm not crazy about spending the ~ $270. Anyone checked the fuel pressure with your standard (auto) fuel gauge?

A regular fuel pressure gauge is fine...

 

[jchrisk]

Today I rode my FJR again. It’s running great, its clean, and no longer taking up the car’s spot in the garage.

First, my apologies. The fuel pump was the obvious culprit. It was the last thing I touched before the real trouble began. I really didn’t want to have to remove it again, and I couldn’t think of anything in that simple component that would be responsible for these symptoms. So I put it off, and had some of you chasing red herrings. Mistake.

I did remove it again, and disassembled it again. It wasn’t obvious at first, so I’ll post a picture here, in case anyone else takes the pump out of a Gen I.

Originally, I pulled the pump to fix the leak in the return nozzle, following this thread. But I missed this comment:

“When you re-assemble dont make the same mistake I did. The high pressure line follows up into the pump half of the whole unit. fish out the o-ring from that and the plastic follower behind it. Put them on the bottom half and then slide the 2 back together. I took some pics but have been too lazy to post them (don't have a posting site)...”

Here’s a picture (to be posted later - guess the site doesn't like shortened urls):

<picture TBD>

If you disassemble the pump into its two parts, make sure you fish this o-ring and the small plastic piece behind it in the main feed nozzle. Re-insert both into the OTHER half BEFORE re-assembling the two parts. Not doing this is what caused fuel to drain continuously into the main feed line.

Did that, put everything back together, and fired it up with the first crank. I still do not understand how this resulted in the very strange symptoms I was getting.

As a bonus, my initial trouble with the idle is gone. Though for the idle trouble, I can’t say if it was new plugs, replacing a corroded spark plug wire, or cleaning the main connector (TownsendsFJR1300 – I checked this again after missing the corrosion the first time. There definitely WAS some corrosion in there – not a lot, but some, and Ive read that that is enough – THANKS!).

Bike is running GREAT! Thanks everyone.

 

[TownsendsFJR1300]

Yep, that connector kicked Yamaha headquarters butt and all their techs (they couldn't find it)

Some dielectric grease in there, you'll NEVER have to open it up again...

(Found it here on the forum way back then)...

Glad your bikes up and running!!!

 

[jchrisk]

The Pic