Revs dropping off majorly when driving

[Dublinrider]

Hi guys, any help or advice is much appreciated.

Basically as I'm driving its as if the engine isn't getting enough fuel and the power drops off, so much so that I'm driving 100kph to 90-95kph

And when I pull back on the throttle takes a sec and then full power returns and the bike accelerates massively.

The plugs on the bike are fine, not sure of anyone else has had this ever happen to them, any ideas are most appreciated.

Thanks guys

Seamus

 

[Motogiro]

:welcome:to our great forum! I see you joined this past June and this is your first post.

Your problem could be anything from poor fuel, fuel delivery, or throttle position sensor (TPS). Early FZ6s were recalled by Yamaha for bad TPS. You might search TPS on the forum and try the test to see if it's defective.

Here's a link with the test procedure includes. You should see smooth number changes on your readout. Closed throttle to wide open throttle will be smooth with out numbers skipping or jumping high or low. http://www.600riders.com/forum/fz6-...ou-experiencing-poor-idle-mileage-stalls.html

Also, have you tried some injector cleaner? We have a product here called Seafoam that works great for dirt injector etc.

 

[TownsendsFJR1300]

:welcome: to the forum!


+1 on Cliff's post. Chevron "Tectron" also works very well as a cleaner.

Did you fill up recently elsewhere and possibly get water in your fuel? Has the bike sat for any lenth of time without a fuel stabilizer/partially full tank?

It sounds like a fuel delivery problem, hopefully its just the injectors.

Also, check inside your fuel tank for any rust. The fuel pump can clog up if the tank is rusty inside, see below pictures:

The first picture is the fuel level switch on the side of the pump. The second, with the orange arrow, show how to release the switch from the pump (while its IN THE TANK), necessary when removing the pump. The last two show the pump actually apart. The screen DOES NOT REMOVE and is NOT replaceable. It must be cleaned as best as possible (should it be clogged)..

Please post how it goes, your results...

 

[YZF73]

Here's a link with the test procedure includes. You should see smooth number changes on your readout. Closed throttle to wide open throttle will be smooth with out numbers skipping or jumping high or low. http://www.600riders.com/forum/fz6-...ou-experiencing-poor-idle-mileage-stalls.html

+1, the first place I'd be looking based on the symptoms.


Yamahaboyz

 

[Humperdinkel]

Seeing as you have an 05 model I'm going to suggest you start at the TPS too :thumbup:... If the recall has been performed there should be a sticker under the seat somewhere , if not then Yamaha should be able to tell if it was done using the chassis #..

 

[TownsendsFJR1300]

Any updates?

 

[Dublinrider]

Hi guys extremely sorry about the huge delay in replying to you all.

Finally got around to performing the tps diagnostic.

Fully closed reads 16 which is normal however fully open it is 101 which is slightly out.

So I will be off to the garage tomorrow to find out what the story is and ill keep you all posted and up to date on what's happening

Seamus

 

[Nelly]

Hi guys, any help or advice is much appreciated.

Basically as I'm driving its as if the engine isn't getting enough fuel and the power drops off, so much so that I'm driving 100kph to 90-95kph

And when I pull back on the throttle takes a sec and then full power returns and the bike accelerates massively.

The plugs on the bike are fine, not sure of anyone else has had this ever happen to them, any ideas are most appreciated.

Thanks guys

Seamus

Welcome to the site, plenty of great info from a good bunch of people.

Let us know what the issue is when you find it.

Neil

 

[TownsendsFJR1300]

Hi guys extremely sorry about the huge delay in replying to you all.

Finally got around to performing the tps diagnostic.

Fully closed reads 16 which is normal however fully open it is 101 which is slightly out.

So I will be off to the garage tomorrow to find out what the story is and ill keep you all posted and up to date on what's happening

Seamus

Going over that little bit is fine however you have to slowly check ALL the numbers inbetween when opening and closing the throttle. They should NOT skip or be missing any numbers.

Checking when the bike is to temp also is a good idea, sometimes the TPS acts up only when hot..

Good luck..

 

[Ruggybuggy]

Going over that little bit is fine however you have to slowly check ALL the numbers inbetween when opening and closing the throttle. They should NOT skip or be missing any numbers.

Checking when the bike is to temp also is a good idea, sometimes the TPS acts up only when hot..

Good luck..

Correct, at the shop we scope TPSs with an OTC Genisys. We can graph the reading so you can see if the signal drops out. Sometimes it happens so quickly there is no other way to properly do it.

 

[TownsendsFJR1300]

Correct, at the shop we scope TPSs with an OTC Genisys. We can graph the reading so you can see if the signal drops out. Sometimes it happens so quickly there is no other way to properly do it.

Is that for an automotive application or bike (or both)Dave?

I know the manual has you setting the TPS by voltage on the FZ. As for actually checking the TPS with a meter, they check the resistance with a meter(4-6Kohm (symbol I believe).

BTW, (and off topis for a sec) did you notice any difference with the throttle sync?

 

[Ruggybuggy]

The OTC is hook up in parallel with the ground wire from the sensor and the return voltage. Turn the key on and twist the throttle and it will graph the voltage from the start to the end and you will see a nice progressive line from say .5V to 4.5V ( if that's what the FZ spec is) on the scope. Any glitches will show on the graph. You can also hook it up directly on the Ohms scale and graph it that way as well but you won't be able to determine if you loss your reference voltage.

I have to say I didn't notice much with the TB sync but it was expected considering how little it was out. But it had to be checked anyways and surprising it wasnt out further.

 

[Dublinrider]

Hi guys have my local dealer running the chassis # through to see if it is up for a recall.

Ill double check the diog mode with the bike hot.

Kinda ran through the closed to open stage number by number and all seemed to check out fine.

Been using a injector cleaner but to no avail, saying that the problem with the revs only occurs from time to time which is quite frustrating trying to figure exactly what is up with it.

Tank from the top looks like there is a slight bit of rust, anyone know of any good treatments etc for the tank to help remedy the rust.

Thanks again for all the help lads

Seamus

 

[TownsendsFJR1300]

Hi guys have my local dealer running the chassis # through to see if it is up for a recall.

Ill double check the diog mode with the bike hot.

Kinda ran through the closed to open stage number by number and all seemed to check out fine.

Been using a injector cleaner but to no avail, saying that the problem with the revs only occurs from time to time which is quite frustrating trying to figure exactly what is up with it.

Tank from the top looks like there is a slight bit of rust, anyone know of any good treatments etc for the tank to help remedy the rust.

Thanks again for all the help lads

Seamus

If you can see rust, the tank likely has rust laying at the bottom and may very well be just starting to clog the fuel pump (very common with rusty tanks).

Its possible the filter is borderline clogged allowing just enough fuel to flow (run normally). Its likely going to be the next step to do if the TPS checks out.

There are some posts re cleaning the tank (chemical, galvanic chemical re-action, etc).

Below pic's are of the fuel pump clogged up. The filter cannot be removed, might get it cleaner on the outside of the screen....


Good luck...

 

[TownsendsFJR1300]

Any updates??????????

 

[n0other]

Can you elaborate on the sticker? I dunno if mine was done, I've read that there should be a punch mark above the VIN on the frame, my bike doesn't have it, but your post gives me hope still!

Seeing as you have an 05 model I'm going to suggest you start at the TPS too :thumbup:... If the recall has been performed there should be a sticker under the seat somewhere , if not then Yamaha should be able to tell if it was done using the chassis #..

 

[aid-90]

I am starting to have the same issue. my bike is a 2004 and the recall was done. have a receipt from the previous owner.

I could be driving and the bike would go dead for a split second and then shoot back to life, which is quite worrying
Would the tps have failed?
never thought of rust in the fuel tank?

 

[Motogiro]

I am starting to have the same issue. my bike is a 2004 and the recall was done. have a receipt from the previous owner.

I could be driving and the bike would go dead for a split second and then shoot back to life, which is quite worrying
Would the tps have failed?
never thought of rust in the fuel tank?

That could be your kill/engine stop switch.

 

[aid-90]

That could be your kill/engine stop switch.

Should I take the killswitch assembly apart... check the connections? spray with wd40? how would i go about bypassing the switch?

Thanks :thumbup:

 

[FinalImpact]

An engine that just turns off is very different than one which starves for fuel. For the OP I would suspect something is plugged as Scott pointed out OR the hose from the Fuel pump is kinked. << This last condition allows it to start, run, idle, and work pretty normal until the load on the engine goes up (when it needs more fuel).

I'd lift the tank and remove the high pressure hose for inspection.

As for the Kill switch, three screws and it opens up. You can jumper it on to verify/and/or eliminate it as the source of the problem. Do search, there are several threads with pictures... key words; jumper, kill switch.