Plugged fuel filter?

Yamaha FJR Motorcycle Forum

Help Support Yamaha FJR Motorcycle Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Hang in there Howie, you will win.

BTW, my Harley doesn't have these issues! Just sayin'.... :laughingsmiley:

 
Minor victory tonight....got rid of the #16 fault code.

Haven't touched the Feej in two days, waiting for the weekend for daylight and plenty of time, but decided to go take a look under the "hood" in preparation for doing an AVCC install while the Feej is apart.

Clicked on the ignition and there it still was...the #16 fault code. Damn.

Decided to yank the fuel rail to get a good look at the throttle cable pulley tang for the bead chain mount. I'm supposed to drill a hole in that tiny damn tang???

Anyway, while I had the rail off, I checked the resistance on the TPS, which can cause a #16, but it read just fine. Plugged the TPS connector back in and the #16 disappeared!

Yep, just unplugging it and plugging it back in cleared my #16 fault code.

Small victory, but a win is a win, right?

Don't have to work Saturday. I'll have ALL day to shotgun my no-running problem.

 
Minor victory tonight....got rid of the #16 fault code....

Anyway, while I had the rail off, I checked the resistance on the TPS, which can cause a #16, but it read just fine. Plugged the TPS connector back in and the #16 disappeared!

...

Small victory, but a win is a win, right?

...
It might just be a BIG victory. If the bike can't read the TPS properly, the engine isn't going to run properly. Keeping fingers crossed for you.

 
There are some 05's for sale somewhere, howie....ya may want to look into that. Yer skoot is a lost cause.

 
yeah, you could help him by doing a web search for 05's with low mileage. I'm sure he'd appreciate it....whilst he's busy working on his broke *** skoot.

 
I've sobered up now, after getting completely hammered following an unsuccessful 12 hour marathon trying to get my Feej running.

Borrowed a digital multimeter from the station engineer and traced every fooking wire in the engine bay, looking for opens, closes, faults and ****-ups. I can honestly say the electrical system is 100%.

Even yanked the valve cover to make SURE the cams hadn't slipped timing. Everything checks out there, as well. Oh, forget checking the timing marks on the front of the cam sprockets with the motor in the frame. Side benefit from this little exercise? New coolant and dumped the PAIR system. Mucho better on the clutter in the engine bay. Also discovered it was MUCH easier to disconnect the push-pull throttle cables at the grip to move them out of the way than try to finagle the cover out of the engine bay with the cables in the way, even when re-oriented as shown at fjr1300.info.

With sore fingers, aching back and microscopically small frustration threshhold, I buttoned everything back up to attempt to launch. Fffffffffttttttttttt......runs for a few seconds and dies. No change. VERY frustrating after 12 hours of careful inspection and attention to detail.

The only thing I can think that can be wrong at this point is a problem with the fueling system, specifically, a dead FP regulator. What makes me think this? Read THIS earlier post. I'll recap for those unfamiliar with Gen I fuel flow characteristics.

The Gen I is a "return feed" FI system. That is, when the fuel injector rail is pressurized by the fuel pump, unused fuel is returned to the tank via a spigot on the bottom of the fuel pump. At high manifold vacuum conditions, i.e., idle and low to medium throttle openings, the fuel pressure regulator, which works off manifold vacuum, is open, allowing pressure to be bled off the fuel rail back to the tank. This lowers the fuel pressure to the injectors, effectively reducing the fuel flow when it's not needed, at idle and low throttle openings.

As the throttle opening increases, the vacuum at the manifold drops, and the fuel pressure regulator closes incrementally based on the amount of intake vacuum. So at high throttle openings, vacuum drops, the FP regulator closes and fuel return to the tank stops, increasing fuel pressure at the injectors as needed for large throttle/high rpm operation.

So for anyone with a normally operating system, if you disconnected the return fuel line from the FP regulator at idle, fuell would flow out of it, as the FP regulator would be open to allow return feed to the tank.

HOWEVER, I get NO fuel flow out of the regulator outlet at idle which means one of two things....my fuel pump is toast from the rust clogging, or my FP regulator is toast from the rust clogging. Yet when I pull the fuel feed line off the fuel rail, fuel flows like a mofo when I trigger the pump. Like I've said previously, it'll fill up a quart mayonaise jar in about 10 seconds, so the pump appears to be okay.

What I need to ask the collective is fairly simple....IF the FP regulator IS the problem, and it won't "open", allowing fuel return and lower fuel pressure, would the increased fuel pressure be enough to prevent the Feej from running more than just a few seconds? I have not been able to get the bike to run more than 10-15 seconds at a time, yet the brand new plugs are very black and sooty, as in "WAY TOO RICH!" Not wet, mind you, as in an extremely flooded engine, but very black and sooty.

Basically, I'm asking is the fuel pressure THAT critical just for running at idle? May sound like a stupid question, but I'm graspin' at straws here, folks.

I'm trying to think of a way to bypass the FP regulator completely just to see if I can get it to run for more than a few seconds. At least at idle, when the FP regulator theoretically is "open", bypassing it completely should be okay.

 
What I need to ask the collective is fairly simple....IF the FP regulator IS the problem, and it won't "open", allowing fuel return and lower fuel pressure, would the increased fuel pressure be enough to prevent the Feej from running more than just a few seconds? I have not been able to get the bike to run more than 10-15 seconds at a time, yet the brand new plugs are very black and sooty, as in "WAY TOO RICH!" Not wet, mind you, as in an extremely flooded engine, but very black and sooty.
That seems to make sense. The ECU only tells the injectors to open for a specific amount of time. The ECU would have been tuned for lower throttle positions taking into account the lower fuel pressure. With the bypass stuck closed, the ECU would still open the injectors for the same amount of time, but the higher pressure would push more fuel through during that time.

 
...The ECU only tells the injectors to open for a specific amount of time...With the bypass stuck closed, the ECU would still open the injectors for the same amount of time, but the higher pressure would push more fuel through during that time.
While using the cold start FI map.

 
Okay, here's what I tried....

Got me a 2 foot piece of 1/4" OD fuel line that fits tight in the end of the fuel rail where the FP regulator goes. Hooked it up to the return line with an inline barb, effectively bypassing the FP regulator.

Ran the Feej through the launch sequence.....nothing, except running the battery flat.

Still no joy.

I'm JUST about done with this. But honestly, can NOT afford to take it to a dealer. Financial times, ya know.

Gotta decide which way to go with this. Silver Streak may be going on the auction block. :angry:

Plus, it's time to put a fork in this thread. It's about as done as I am.

 
Hang in there buddy. You may be a dork from Florida, but I love's you anyway and we'll get you going again.

Ok RH, I am digging in my SM trying to get up to speed on this. I ain't no meckanik however. Have you pinged radman? Or even Jestal?

Not sure I am totally up to speed on everything you have done, but here goes................

Why not just replace the fuel pressure regulator? How much does one of them bad boys cost? Ebay? Based on what that rust in your tank did to your pump and injectors, it seems fairly logical that there is an excellent chance that same rust ***** is messing with the operation of your fuel pressure regulator. No doubt it still flows, but is it keeping the proper pressure differential as designed?

Theorhetical question: HOW important is the proper pressure differential?

If I understand you correctly, you bypassed the FPR altogether in your last go-around? Though I surely don't know for certain, I would think that would be a bad thing. I think it's a fairly critical part of the system.

If $$$ is an issue, is there another FJR owner who would be willing to let you 'borrow' their FPR to see if that cures your problem?

Since you know the pump and injectors are good, I would next be looking at the FPR itself. Then perhaps the fuel rail (clogged?), or one of the lines? I guess the question is, where else in the system could that rust gunk have caused a flow/pressure problem?

...The ECU only tells the injectors to open for a specific amount of time...With the bypass stuck closed, the ECU would still open the injectors for the same amount of time, but the higher pressure would push more fuel through during that time.
While using the cold start FI map.
Ok Alan, your a fart smeller, but why does the cold start have anything to do with it? From my understanding, injection pulse is strictly a time based evolution that the ECU determines. During cold enrichment, the ECU simply adds more time to the injector pulse based on coolant and intake temperatures. As the engine warms, it decreases the amount of enrichment by reducing injection duration (time).

So a problem with the FPR WOULD cause unreliable injection regardless of cold start or not, because the ECU is counting on a constant pressure to calculate the correct injector duration - for any part of the injection map. If that pressure is more, or less than it's supposed to be, it's got to affect the amount of fuel being injected and how the motor runs. The question is, how much?

Right?

 
Last edited by a moderator:
As I understand things, you are a bit wrong in some areas below. Not sure if it makes a damned bit of differnece, but I am trying to understand all this.

The Gen I is a "return feed" FI system. That is, when the fuel injector rail is pressurized by the fuel pump, unused fuel is returned to the tank via a spigot on the bottom of the fuel pump.
Not quite. The fuel pump itself has a Pressure Relief Valve (completely independent of the FPR) that dumps excess fuel pressure back to the tank (if necessary) long before it hit's the fuel rail. And it's not 'unused fuel that is returned from the fuel rail back to the tank via the fuel pump spigot, but *excess pressure* is dumped when necessary to keep a CONSTANT pressure differential.

At high manifold vacuum conditions, i.e., idle and low to medium throttle openings, the fuel pressure regulator, which works off manifold vacuum, is open, allowing pressure to be bled off the fuel rail back to the tank. This lowers the fuel pressure to the injectors, effectively reducing the fuel flow when it's not needed, at idle and low throttle openings.
While the high vacuum does signal the FPR to release pressurized fuel from the rail reducing the fuel pressure, it does this to achieve a CONSTANT pressure differential between fuel pressure and intake manifold pressure effectively keeping fuel flow constant (from the ECU and injector's eyes). Semantics, I know, but I think it's an important distinction.

As the throttle opening increases, the vacuum at the manifold drops, and the fuel pressure regulator closes incrementally based on the amount of intake vacuum (EDIT: should be intake pressure). So at high throttle openings, vacuum drops, the FP regulator closes and fuel return to the tank stops, increasing fuel pressure at the injectors as needed for large throttle/high rpm operation.
Again, amount of fuel is not controlled by the FPR or the total amount of fuel pressure. FPR is just there to keep the pressure differential between fuel pressure and intake manifold pressure CONSTANT. Injector pulse duration determines how much fuel is injected and is calculated based on a known, CONSTANT, fuel pressure differential by the ECU.

So for anyone with a normally operating system, if you disconnected the return fuel line from the FP regulator at idle, fuell would flow out of it, as the FP regulator would be open to allow return feed to the tank.
HOWEVER, I get NO fuel flow out of the regulator outlet at idle which means one of two things....my fuel pump is toast from the rust clogging, or my FP regulator is toast from the rust clogging. Yet when I pull the fuel feed line off the fuel rail, fuel flows like a mofo when I trigger the pump. Like I've said previously, it'll fill up a quart mayonaise jar in about 10 seconds, so the pump appears to be okay.
I am following your line of thinking here, however, just because you get *flow* from the fuel pump, doesn't necessarily mean you are getting proper *pressure*. I thought you replaced the fuel pump? Is that not correct? The other big question is: On a properly running FJR, how much fuel is actually returned by the FPR to the tank at idle? LIttle? Lots?

What I need to ask the collective is fairly simple....IF the FP regulator IS the problem, and it won't "open", allowing fuel return and lower fuel pressure, would the increased fuel pressure be enough to prevent the Feej from running more than just a few seconds? I have not been able to get the bike to run more than 10-15 seconds at a time, yet the brand new plugs are very black and sooty, as in "WAY TOO RICH!" Not wet, mind you, as in an extremely flooded engine, but very black and sooty.
I think that is a very possible outcome. However, just one of many. :blink:

Basically, I'm asking is the fuel pressure THAT critical just for running at idle? May sound like a stupid question, but I'm graspin' at straws here, folks.
A good question I don't know the answer to. I think your next step is to either borrow or purchase a Fuel Pressure Regulator. Or somehow test it's operation with a pressure gauge? And ditto for the fuel pump if it's the original one that had all that crap in it.

 
Last edited by a moderator:
Newbie here who has read this thread with much interest. Trying to be objective the bike ran kind of OK before you discovered the rust in the tank? THen you cleaned the rust out of the fuel pump and the injectors? Now the bike doesn't run properly. If it were me, I would be trying hard to find another tank/fuel pump to at least try. Just because the pump squirts into air doesn't mean it can pressurise the fuel line adequately. The fact that the bike was stalling when your fan came on suggests the fuel pump was pulling an almighty current just to overcome the dirt. I would concentrate on what you have changed altho it does sound like you have changed an awful lot in search for a fix! Good luck and keep at it if only to keep your readership enthralled.

 
Hang in there buddy...

While using the cold start FI map.
Ok Alan, your a fart smeller, but why does the cold start have anything to do with it?...
ASSuming that the run problem is fuel related, the issues will be too little fuel, too much fuel or improperly timed fuel delivery. I only mentioned the Cold Start FI map because it will take a possible over rich condition and put it way over the top. RH's black sooty plugs reinforce the too rich scenario. If RH's engine were up to operating temperature so that the Cold Start map is not being executed, there is a chance that his engine would run. Maybe not run well, but it would run.

I believe we can discard the fuel timing, this leaves too rich or too lean. First thing I would suggest RH does is ditch the sooty black plugs and install a new set of plugs, this will do wonders for ignition. A too lean condition will usually cause popping and rough running. I believe I read that for the few seconds the engine runs it is mostly smooth. Too rich will cause bogging, intolerance of the throttle being twisted and as the plugs load up with excess unburnt fuel you get flame-out.

Is there anyone that can perform a mission of mercy and loan RH a fuel regulator? Say there Skoot, don't you have a spare FJR just sitting around? ;)

 
Last edited by a moderator:
Volume does not equal pressure. A pump can have volume but no pressure. You could try to backflush the FP reg, no doubt it's loaded with that crap you called fuel. Replace it in any case, far cheaper than a fuel pump-but I have a strong feeling there isn't much in that fuel system that is good anymore. Might as well have run sand through everything. Bet the inside of the rail is clean though. For those of you inclined to remove the fuel rail in the future, invest in an hand impact driver, and a set of JIS standard screwdrivers. Tends to make life much easier.

 
If I understand you correctly, you bypassed the FPR altogether in your last go-around? Though I surely don't know for certain, I would think that would be a bad thing. I think it's a fairly critical part of the system.
I've no doubt it is VERY critical. The attempt was simply to see if I could even get the sucker to idle more than 10-15 seconds without stalling. My logic told me "at crank/idle, vacuum is at its highest, so FPR is at its 'openest'", since for any point in the "run" cycle, at crank/idle is when the pressure to the injectors is at its lowest. By eliminating the FPR in the chain altogether, just for an idle test, I hoped I might pinpoint an FPR issue.

Since you know the pump and injectors are good, I would next be looking at the FPR itself. Then perhaps the fuel rail (clogged?), or one of the lines? I guess the question is, where else in the system could that rust gunk have caused a flow/pressure problem?
Well....there might be the issue. I "know" the injectors are good, because I had them professionally cleaned, flowed, etc. I can NOT say the pump is "good", at least good in the sense that it is up to the task of running an FJR. The pump IS pumping...flow is high, but without actually doing a pressure test, I can't say with 100% certainty that it actually is "good". As Rad pointed out...

Volume does not equal pressure. A pump can have volume but no pressure.
...my problem may hearken back to the fuel pump itself. I have been, and quite possibly incorrectly, assuming that a surgical cleaning of my pump took the pump out of the equation. But it's VERY possible that the original rust infestation didn't so much as plug the pump (which of course it did) but actually wrecked the pump in the process.

To quote Rad again...

Might as well have run sand through everything. Bet the inside of the rail is clean though.
Yep...the inside of the fuel rail is mirror smooth. :)

But the pump may simply just not be putting out enough pressure. In retrospect, after effin' with this for a month now, a fuel pressure test is probably the 1st thing I should have had done after the cleaning. Just HAD to try to fix it myself, plus, without being able to drive the bike to the shop to have a test done, it's kinda been a moot point....until now.

Something Alan said above also might help pinpoint a fuel pump issue.

A too lean condition will usually cause popping and rough running. I believe I read that for the few seconds the engine runs it is mostly smooth. Too rich will cause bogging, intolerance of the throttle being twisted and as the plugs load up with excess unburnt fuel you get flame-out.
"Mostly smooth" is being VERY charitable. Alan mentioning the "popping" is what comes to mind. As I mentioned, the bike will run for a few seconds, but many, if not all the times it dies again, it is accompanied by backfiring at the moment of death. Too low a pressure from a bad pump would definitely cause a lean condition.

Guess I need to "bite the bullet", find a friend with a trailer, and drag this heap over to the dealer and spend some diagnostic dollars.

Maybe I can get them to pinpoint a specific problem, then go from there. Just have to make them fully understand that ALL I want is a fuel pressure test and FPR test, just like what is outlined on pages 7-38 & 7-39 in the "book". This can be done without the bike running, by going into the diagnostic mode and selecting any of the modes that power the fuel pump, such as #9, the voltage reading mode.

I'm done with this until I can get a pro to look at it.

Thanks,everyone, for playing along with the Home Edition of "The Dork from Floh-uh-duh!"

 
Yup. You NEED to get that fuel pump checked out. And frankly, after seeing the photos of that mess, I would replace the Fuel Pressure Sensor no matter what. Heaven forbid you end up getting a new fuel pump just to have all that **** that's still in the FPR go through it and the injectors.

You know anybody that has an FJR that you can borrow their fuel pump or FPR? That would be a cheap, if not time-consuming way to diagnose everything.

Guess you won't be letting your poor FJR sit with a half empty tank anytime soon, will you? I thought I was hard on my dirty ol whore, but you are just plain abusive to your gal.

Oh yeah, :****:

 
Last edited by a moderator:
Yup. You NEED to get that fuel pump checked out. And frankly, after seeing the photos of that mess, I would replace the Fuel Pressure Sensor no matter what. Heaven forbid you end up getting a new fuel pump just to have all that **** that's still in the FPR go through it and the injectors.
You know anybody that has an FJR that you can borrow their fuel pump or FPR? That would be a cheap, if not time-consuming way to diagnose everything.
You meant "Fuel Pressure Regulator", didn't you?

I have an old ZRX buddy close by who purchased an '04 like mine a year or so ago. Haven't crossed paths in a while, but I'm gonna give him a call.

The IDEAL thing would be to simply swap tanks and FPRs for about 5 minutes and see if Silver Streak purrs like the kitten she used to be.

Guess you won't be letting your poor FJR sit with a half empty tank anytime soon, will you? I thought I was hard on my dirty ol whore, but you are just plain abusive to your gal.
Hell, ain't that what wimmins is for???

Oh yeah, :****:
Back atcha, Nancy. :)

 
Top