High idle that won't adjust down

[FinalImpact]

Yes, but it I do feel it would have to be some special circumstances to be "cold" outside and raise the idle while the engine is not feeling this same cold? Yes? I'll take that input as cold has some impact. To what extent is a little unclear. That said, Im not throwing it away as it makes sense go verify the thermal sensors...

From a mechanical standpoint, the cold coolant will open the IACV and add air. Period. It's all mechanical and no ties to the ecu. However, the ecu adds fuel based on rpm as the coolant temp is secondary in the chain events assuming the TPS is reporting the throttle plates as closed.

Think of the RPM and TPS inputs as a 12" wide paint roller covering a lot of area. Then the water temp sensor as touch up paint brush followed by the air temp sensor being a fine tip arts and craft brush.
As far as "temperature inputs go" the water temp has a bulk of the say so in regards to engine fueling... the air temp much less.

That is not say the air thermistor is not important, it is. But under no load idle conditions rpm, IACV position (based on coolant temp), and vacuum sensor call the shots....

In short a mild vacuum leak adds air so the engine adds fuel to match it until it reaches some point where it throws an error code as it simply cannot account for the "additional air" as the TPS says the plates are closed. Make sense?

At cruise and under load the rpm, tps, air temp, and vacuum sensors act as a poor mans mass air flow sensor (MAF) to determine engine load and subsequent fueling needs.

 

[FinalImpact]

How about this.....
If the throttle plates are confirmed closed;
While at idle, PLUG THE TWO INLETS to the IACV here....

Where ever the secondary source for air IS, it will become very obvious as it will be sucking like Hoover Vacuum gasping for air!!! A cracked hose will become very apparent!

 

[TownsendsFJR1300]

For the OP, please check here to rule out basic's

In the below pic, one cable is to pull open the throttle plates, the other a SAFETY to return them if there's an issue.

As noted earlier, check and make sure there is some play in both cables by gently pushing with your finger. There should be some slack.
If not adjust the "adjuster screw" inwards to get the desired play. This is also in the owners manual..

Confirm the throttle plates / disc the cables attached to, closes /snaps shut...IMPORTANT

Please report back on this specifically..





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[cman]

Thanks for the help.

All the plugs are present in the sync hoses.
TB clamps and boots are good.
There is slack in the return cable
I didn't run with the airbox off. Will try that tomorrow and check the coolant level.

I'll check temps in the diagnostic mode. I rode today in 80's. At these temps the idle was pretty good. 1300 +/- more plus than minus

Thanks,

Steve

 

[TownsendsFJR1300]

Is there some play in the PULL CABLE??

*** If NOT, it's holding your throttle open.****.AND HIGH RPM's

 

[cman]

Both cables have slack

 

[Motogiro]

A friend and member here on the forum bought a Triumph Daytona 675 bike was great. Hadn't heard from him for a bit and we'd done quite a few great rides together. I get a call from him and his engine failed. He had it in a few shops and finally after over a month or so he gets an answer from the second shop that the engine had bad damage. Rebuilding it was not economically feasible but he did locate a used 675 engine. He got a price to swap the engine and it was very high. Of course I get involved. It took a few days to complete the job and he was happy and anxious to get it done, asking can I do this, can I do that etc. I'd answer yes and depending on what it was related to skill set and hierarchy of reassembly. Got it all assembled and ready for a test start. Vrrroooom right off the bat!. But.....What's wrong with the idle? It was all over the place like the ECU was getting varied signals from sensors or it has a big hole in the intake manifold. After all the head scratching I said let's open the air box. I figure maybe a leaky boot or hose even though I couldn't hear the vacuum leak sound so common with a throttle response like that. I would blip it and it would never settle at one RPM and it was slow to return to it high idle... What the hell?

When he put the air box back on he never removed the paper towel balls I stuck in the throttle stacks to keep debris out........... Pulled them out and it was a great running motor!Blah

 

[KB2WYL]

Well, good the cables both have slack. But still need to verify that the plates are actually closing. PO may have screwed with the butterfly proportioning screw. It's the one in between the throttle bodies. See it in [MENTION=15974]FinalImpact[/MENTION] 's post up there a few. In that picture you can see it in between the two IACV hoses and the Crankcase vent hose. Don't screw with it, just saying someone else doing that could have one set of plates closing while the other set stays open. **They should ALL close ALL the way**

Randy, yes I agree with you, and understand the chain of events. I feel as though we all need a little more info, Steve.

We all started these bits of advice based on your original post where you said: "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"

So, at least speaking for myself, I'm thinking when it's warm the idle is always above 1600, and you can't affect it.

But then you said next that you found another clue: "The colder it is outside, the higher the idle"

So then I was thinking, so when it's cold outside the idle is even higher than 1680rpm!! I mean man, that's a gross leak that's hard to account by ANYTHING other than completely broken rubber somewhere, or open plates.

Last, today you said that you went for a ride, and at temps: "in 80's. At these temps the idle was pretty good. 1300 +/- more plus than minus"


So, no disrespect intended, we just need to know. In order to help you, and for the next person who searches out this thread

Couple simple things...

1.) When you start it and it's cold what is the idle? Is this idle the same EVERY time you start it? And can you adjust idle with idle adjust screw?

2.) Then, once bike has warmed up, what is the idle? Is this the same EVERY time once it's warmed? Now when warm, can you adjust idle with the adjust screw?

Again, no disrespect. When I say "the same", discrepancies of 50rpm are not important here. But discrepancies of hundreds of rpm (going from 1680 warm to just over 1300 warm) are important.

Please, take airbox off and check those plates at least. I think Randy had a great idea with the IACV hoses as well. But let us know about these few questions I'm asking. Your last post really got me thinking we might be exploring all kinds of intelligent solutions from different viewpoints, when all it was to begin with was a stuck IACV from sitting. Blah.


Thanks,
Loren

 

[TownsendsFJR1300]

The bike is "new" to the Op. We don't know how long this issue has been or when the bike was last ridden well..

With a high idle, NOT finding anything unusual and from 4-8 to 4-11-17, three days of running it's improving ON IT's own.

Sounds like something / crap was stuck somewhere in ICV and is working it's way out on it's own...

For the OP, keep riding and putting the miles on... Bet it's NOW getting FRESH FUEL run thru the tank / system..


IMO, I would run some of Yamaha's RINGFREE: https://www.shopyamaha.com/product/details/ring-free-plus?b=Search&d=34

I use it in every gas machine I own. It's very popular in the marine world as it's a fuel system and top end cleaner. Certainly can't hurt...

 

[cman]

Making progress. I did the checks suggested. Coolant and air temps are good. TPS is good. Coolant is full.

I tried adjusting the butterfly proportioning screw. Turning the screw in 1/2 turn brought the idle down. At this point I found the point at which the idle adjust screw started to affect the idle speed. I seem now to have a steady idle at 1200 to 1300 rpm. Yea !

Tomorrow I will hook up the manometer and sync.

Thanks all !

Steve

 

[TownsendsFJR1300]

I tried adjusting the butterfly proportioning screw. Turning the screw in 1/2 turn brought the idle down. At this point I found the point at which the idle adjust screw started to affect the idle speed. I seem now to have a steady idle at 1200 to 1300 rpm. Yea !
.

Thanks all !

Steve

As that center screw has been dinked with, you'll NOW have to make sure cylinders 1 &2 are close to 3 &4 WITHOUT using the air screws...

IE,the BUTTERFLYS are all aligned up...


As you did seem to make progress there, sounds like someone dinked with it BEFORE. So two cylinders had a slightly OPEN THROTTLE....

 

[cman]

Is there a procedure for that ? I don,t see it in the manual. It is marked with paint so I can put it back where it was.

 

[KB2WYL]

It was marked with paint from the factory. Did you look at it before you turned in to see if the paint was still original, as in not just paint to paint but one continuous line of paint not yet broken by turning that screw?

That screw, tightening it (turn in 1/2 turn) opens the butterflies on 3+4 MORE not less. If you opened the butterflies on half of the TB assembly MORE than they were, and idle went down, then you definitely have another gross air leak through rubber somewhere....

Loren

EDIT: The only way I see this working without another leak is if the butterflies on 1+2 were not actually closed. Then, when you tightened that screw, it may have pushed them closed more before starting to open 3+4 more like it should. Remember, this adjustment is made to work by opening 3+4 more *When 1+2 are all the way closed, and can therefore not move any further forward* That is very important, 1+2 closed, and in part is how you calibrate 3+4. But probably verify this first, that the paint was still original, because it sounds to me like it was

 

[TownsendsFJR1300]

Is there a procedure for that ? I don,t see it in the manual. It is marked with paint so I can put it back where it was.

It IS noted in the manual NOT TO TOUCH IT.

If you can still see the original paint mark, set it back to that.

You'll still have to check with the Manometer and a visual wouldn't hurt.

IF TWO outside cylinders are much higher than the others, with the air screws about the same, it's likely way out
I suspect your pretty close right now.

As for a procedure, back around 2004, 2005, an FJR guy (experimented with-see below link) doing an "unauthorized sync" fine tuning with the A/S's could then be done...

For the FZ, there's only ONE screw so WAY EASIER...



As a side note, before I had my Carbtune, I had Yamaha do a sync on my FJR. They TURNED one adjuster (it has THREE for 4 TB's) as the adjustment.

Same as the FZ, it's NOT to be touched. They were lazy and adjusted that screw as the air screw is tucked under a TB. Once I had my tuner, I saw the paint broken, put it back and re-set properly with the air screws...


Unauthorized Throttle Body Sync:
Post #5: 'Unauthorized' TB synch - Technical Discussions - FJRForum


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[cman]

Thanks, It is the original paint mark. I'll set it back and check butterfly positions. It may be possible that the screw was previously turned one full turn in or out so that the paint mark ended up in the same location ? I don't think I have any leaks through rubber.

One more clue. I briefly attached the sync tool and cyl 3 and 4 had much greater vacuum than 1 and 2 to the point that they wanted to suck the fluid out of the gauge. That indicates that 3 & 4 are more closed right, creating more vacuum.

 

[TownsendsFJR1300]

Thanks, It is the original paint mark. I'll set it back and check butterfly positions. I don't think I have any leaks through rubber.

One more clue. I briefly attached the sync tool and cyl 3 and 4 had much greater vacuum than 1 and 2 to the point that they wanted to suck the fluid out of the gauge. That indicates that 3 & 4 are more closed right, creating more vacuum.

Was this BEFORE or after adjusting back to the white mark?

Also, if this is a homemade machine, you likely need a restrictor in all your hoses. An opening approx the size of a needle.

 

[cman]

Before, I have restrictors

 

[FinalImpact]

Something I've done in the past to verify that EIGHT independent throttle bodies were basically flowing the same amount was to measure the flow rate.

Two options come into play: quick and easy **rough set** and then the fine tune.

Rough set is to use something like rubbing alcohol and a syringe. Get unobstructed access to TB. Get a visual on which plates appear to be closed and start here. Measure 5 to 10cc of fluid and dump it into an easy pour container.
With a stop watch ready, dump the fluid into the closed thottle plate and start the timer.
Now adjust each opening to obtain the same leak rate.
You may want to start the engine after doing two cylinders.

In the case of the V8 I was working on I used gas but the TB's were bolted to a single plain manifold that was free of the engine so i could dump as much gas or alcohol through as I wanted.

The goals on an assembled engine; use the minimal to get an accurate measurement and make them all the same. Although not absolutely necessary it is best to get the fluid level high enough to cover the entire throttle plate.

Obviously if you can see a gap fluid will pour right through so its a waste of time to do this.

In the V8 example above, all bodies were independent, had independent adjustable links that all needed synchronized. Once zero'd, then idle stop set screw was used to set idle speed. It was a Cool to look at but a p$ss poor design to setup. It needed an IACV like the FZ!

The other option is airflow using a flow meter or a trick I did earlier in life is a manometer over the venturi. The trick here is to cover the venturi with a plate having a bleed hole in it and your manometer attached and sense the vacuum signal. However with the IACV involved you either set them all the same and assume they are flowing the same or close them as they are an air source that will alter the signal at the stack.

As its very unlikely anyone will take the time to do either of these I'll stop here and finish with the detail that pro shops use fixed volume vacuum source (big vacuum cleaner) and suck through each venturi to sync them and then put them on the vehicle. No guessing this way as the engine as a vacuum pump has been removed from the equation!

 

[cman]

OK, just finished another round and this feels good. I used a machinists steel rule to check butterfly leading edge heights at partial throttle openings. Neither the original butterfly sync setting nor my changed one put them in exactly the same position. After some work they were as close to the same as I can get by eye. A dial indicator would be better but I am confident they are close. At this point the idle adjust screw has started to do it's job ! I hooked up my homemade manometer and proceeded to adjust the air screws. I was able to get pretty close. Haven't ridden it yet but it is behaving much better than when I got I last week.

My FZ1 bar is supposed to arrive today. If it does I'll throw it on. I plan on riding up to VIR to watch the SCCA races tomorrow.

Steve

 

[TownsendsFJR1300]

I REALLY wish you would read that post (#5) in post #34 above. "The unauthorized sync"..

It'll save you a bunch of guessing...