High idle that won't adjust down

[cman]

Hi all,

New here. I just bought a 2006 FZ6 for a great price with a few issues. Nice bike. My other is a Triumph Sprint RS.

The one that is baffling me now is the idle. When warm it idles around 1680 RPM. I found the idle adjust screw but turning it has no effect on idle speed, up or down. The bike has about 13k miles and runs great otherwise.

Any thoughts ?

Thanks,
Steve

 

[Motogiro]

:welcome: to the forum Steve!

Look to see if the screw is actually mechanically present. In other words the the screw should rest on a tab so that the throttle plate shaft can be adjusted. Are you positive you are on the idle adjust screw?

 

[TownsendsFJR1300]

Sounds like an issue with the throttle bodies (located under the air filter box) or the PO messed with the throttle body sync.

I would first inspect the TB's.

There are 4 hoses that come off of each TB. There SHOULD be a plastic plug in the end of each of them (removed for doing the sync ONLY).

If one is missing, you have a major vacuum leak and idle issues.

***With the tank lifted, they'll be TWO hoses on each side right up against the frame (or should be).


One member here had a hose that was cracked (right where it attaches to the TB) so some digging is in order. ( KB2WYL )

If nothing is found missing, hoses good, the PO may have messed with the TB sync. Do you have a SHOP MANUAL?

You'll also need a manometer for a correct sync.

Check those hoses first, anything unusual, dinked with etc and report back.

PM sent as well...

 

[cman]

Thanks for the replies. Seems to be a vacuum leak. I'll go looking. Just read the make your own manometer thread. A project for today.

Steve

 

[Motogiro]

If you have a vacuum leak wouldn't adjustment of the throttle plates still vary RPM? I realize a bad vacuum or throttle body synchronization can lead to other radical adjustment regarding idle but I would still check the possibility of mechanical integrity of the idle adjustment first.

Sent from Moto's Motorola

 

[TownsendsFJR1300]

If you have a vacuum leak wouldn't adjustment of the throttle plates still vary RPM? I realize a bad vacuum or throttle body synchronization can lead to other radical adjustment regarding idle but I would still check the possibility of mechanical integrity of the idle adjustment first.

Sent from Moto's Motorola

In his first post, quote: " I found the idle adjust screw but turning it has no effect on idle speed, up or down".

I can't bold parts of the above, but I take it. he has turned that adjustment screw on the port side and it doesn't affect idle at all.

With the idle that high, as it sits, adjusting the idle stop screw would have no affect as the RPM's are way too high.

For the OP, should you not find anything, go to the sync page in your manual.
*** The #1 cylinder air screw (base cylinder) SHOULD be about 3/4 a turn OUT from
lightly seated.

Check to see if anyone dinked with that.

Set it back to 3/4's and then set the others from there.
Should you run out of adjustment with another cylinder, OPEN #1 to 1 full turn.

That will give you more adjustment on the other cylinders...

 

[cman]

Just bought all the parts locally to make a monometer save for the Dorman bits which are ordered now. Going out to inspect the sync hoses etc.

Thanks for the help !

Steve

 

[FinalImpact]

Assuming someone didn't jack with it, it seems very likely a vacuum leak at the main sensor as any single cylinder leak would not raise the rpm that much.... I would start by removing the air box for a peak. You'll need a looooooong 3mm allen. A ball end works best.

Shown here on the right is the sensor. The hose conects from the bottom.

This is from another thread... gives you the layout of what to look for. The blue junctions are plastic and suspect.

Pictures here are none CA hose routing....
The blue blocks are plastic. Make sure none are broken and none of the lines leak.

Verify it is connected like so....

From Final Impact Bike P O R N album...

 

[TownsendsFJR1300]

Any updates???

 

[KB2WYL]

Yeah, we want to know what happened Since there have been a few great opinions so far, if you haven't checked it yet...FWIW, from experience recently, I second taking the airbox off in any case, and checking all of it. You said you were going out to do that, last post. Yes it sounds like a leak, and yes, the airscrews being too far out of adjustment could cause it. Use the diagrams that were posted to check all lines. I had a few lines where integrity looked fine to the naked eye, yet leaks were still present. Check ALL lines for leaks, and then proceed.

Reason being, it's not hard to do, and you're going to want to cross them off the list. After that, homemade manometer will get you close (follow Scott's 3/4 turn on #1 advice) enough for now, but my experience was that real gauges are superior to any fluid manometer. Whether the Vaccummate/Carbtune vertical type, or classic round gauges, it is important to have something which responds to changes quickly. This way you can set it and be done, as opposed to watching your homemade job change more and more slightly after each adjustment as your engine heats up past safe. You'll see when you use it, if you haven't already.

Thick fluid (like the 2 cycle oil in most online examples) = safe but slow to respond so very hard to get them really balanced. Thin fluid = not so safe, faster, still not as good as gauges. So yeah......

Also, make sure that the idle screw is not screwed in or out all the way. About 7 turns out (half way) is a good starting point. Just as you can't adjust idle with air screws out of whack,or vacuum leak, you also can't adjust the air screws properly if idle screw is all the way in or out.

Check everything for leaks.
Idle screw half way out
#1-4 air screw 3/4 out
Start and set idle close to 1300 using idle screw
Sync #2-4 air screws to same vacuum as #1 is
Make sure you still have good adjustment of idle screw (say 800-1600 RPM)

That should get your idle back AND give you peace of mind that all is well. Then when you get real gauges or meters, easy to just hook up and do the sync again.


Loren

 

[Motogiro]

I see said the blind man... I thought it was a mechanical throttle plate type adjuster

Thank you FI!

 

[FinalImpact]

I see said the blind man... I thought it was a mechanical throttle plate type adjuster

Thank you FI!

That's not to say someone didn't mess with it in other ways!

You know nothin John Snow!!!

"You" meaning us! lol

 

[cman]

I took the airbox off and can,t find any obvious problems there. All of the hoses are intact and where they belong. I should be able to do the sync this week when the fittings arrive. Another clue....ambient temperature makes a difference. The colder it is outside, the higher the idle. Engine temp has no effect. The PO changed spark plugs recently but I didn,t see anything out of place. The # 1 screw was just a hair less than 3/4 out.

Steve

 

[TownsendsFJR1300]

You may end up pulling that assembly apart and have some carb / brake cleaner handy.

It's starting to sound like some passages are clogged up then. The higher idle when cold is normal but SHOULD settle down after a
couple of minutes. Sounds like perhaps your not getting warm coolant in there(as it warms, it lowers the idles) or again, it's clogged up inside...

If the bike sat for a long time, got water in the system, etc, all that contributes..

 

[ozgurakman]

I took the airbox off and can,t find any obvious problems there. All of the hoses are intact and where they belong. I should be able to do the sync this week when the fittings arrive. Another clue....ambient temperature makes a difference. The colder it is outside, the higher the idle. Engine temp has no effect. The PO changed spark plugs recently but I didn,t see anything out of place. The # 1 screw was just a hair less than 3/4 out.

Steve

Did you checked if there is enough coolant in engine?

F5121 cihazımdan Tapatalk kullanılarak gönderildi

 

[FinalImpact]

I took the airbox off and can,t find any obvious problems there. All of the hoses are intact and where they belong. I should be able to do the sync this week when the fittings arrive. Another clue....ambient temperature makes a difference. The colder it is outside, the higher the idle. Engine temp has no effect. The PO changed spark plugs recently but I didn,t see anything out of place. The # 1 screw was just a hair less than 3/4 out.

Steve

Do you have a large syringe or handheld vacuum pump or even a little propane tourch?

Did you verify all of the stoppers are in the sync plugs?

These lines...

Also inspect here and confirm TB to head clamps are tight. Boots have no tears....

And the return cable needs slack. The throttle plates should snap closed with crisp solid metallic sound. Verify the shafts stops are seating...

Honestly I'm still inclined to think you have a huge vacuum leak. Did you start it with the air box off and listen for air sucking? Move hoses while its running?

No error codes displayed? Hose cracks may not be obvious unless you have the hose in your hand bending it exploiting the damage....

 

[FinalImpact]

Scott I dont think that is a problem here. However, if the idle air control valve (IACV) were plugged, that would be a good reason to manually force the throttle plates open but if the IACV passages were plugged it would not idle at all as it would be starving for air!!!

Because engine temp change changes idle speed that implies the IACV is basically working but has another air source.

 

[FinalImpact]

I took the airbox off and can,t find any obvious problems there. All of the hoses are intact and where they belong. I should be able to do the sync this week when the fittings arrive. Another clue....ambient temperature makes a difference. The colder it is outside, the higher the idle. Engine temp has no effect. The PO changed spark plugs recently but I didn,t see anything out of place. The # 1 screw was just a hair less than 3/4 out.

Steve

This.... two quick tests to verify sensors work as intended.
With key off hold both set and reset gauge buttons down, turn key on and continue holding buttons down for 10sec to enter diagnostics....

With the engine cold go to diagnostics:
05 = Air Box Temperature
06 = Engine Coolant Temperature

More info here; Diagnostics Mode
With the engine warm, the two # should reflect actual values; Like if it were so warm as to turn the fan on, expect 200°F from the coolant. Air box does get heat soaked from the hot engine at idle vs riding.... best guess as to what it reads when checked but it is the coolant temp that operates the IACV which contols idle speed, not air temp.

Here you see the S2 reporting ambient cold conditions... #5 #6

S2 In Diagnostic Mode:

 

[TownsendsFJR1300]

It could very well be simply too tight a throttle cable.

The bikes new to him and who knows what the PO has done to it.

We assume it's as it should be, but of course, anything dinked with incorrectly by the PO could have very well caused this issue...

We're checking things that could go wrong, NOT SELF INDUCED issues...


*On this bike, we probably need to start from the throttle down and assume everything is dinked with..

 

[KB2WYL]

Agree with everything so far, but remember, he said that *engine temp has NO EFFECT*

As I posted, I agree visual inspection not necessarily enough to rule out hoses. But, if engine temp has NO effect then I doubt it's IACV related, or Air Mix....

Well, air mix screws at least....Sounds like either gross vacuum leak or the Throttle plates (throttle plates sounding probable if engine temp) has NO effect...

Yep, top down. Start with cable and plates.

You'll get to do your sync when done, but don't concern yourself with that right now. You can't even perform it without first getting idle sorted out.


Loren