Revs wont drop to idle

[Carl0s]

So, XB12 -05 Drummer exhaust and racemap.

Problem is, that when the engine is revved, the revs come down realy slow, and when they hit 2000-2500rpm, you need to manualy pull them under the 2000rpm by clutch, in order to get it back to idle.

Same thing goes for decel, if im going to stop to trafic lights, and i pull the clutch before the revs set under 2000, i need to use the clutch to pull them back to idle.

So, i guess ill have to do some minor adjustments by EMC spy, but how, should i go for complete fuell cutoff when the throtle is closed, and the engine is above <1500rpm or should i try some bit more delicant aproach ?

[uly luigi]

Hanging Idle is fairly common, I think some members have gotten around it on the pre-08's by lowering the idle setting just a touch, instead of 1k idle while hot, try to get it down to about 800, oh, did it just start doing this, or has it been an ongoing issue?, if it all of a sudden started after months of trouble free, it might be an intake leak, are your cables lubed good? check if the throat of the throttle body is clean, may be some gunk keeping the butterfly from closing completely, do you have the breather reroute?

[Carl0s]

Nope, its been doing it always. Was eaven worse on the stockmap, racemap helped a bit.

Got breather rerouted, and the cleaned the thortle when i bought the bike. been clean ever since.

You mean lower the idle form the adjuster knob, or by taking some fuell of the map ? Tryed adjusting the knob, but inorder to get it idle <1000rpm hot, the normal idle is so low that the engines idle noises doesent sound healthy anymore.

[uly luigi]

from the knob, don't take it down too low, just a little, it may be lean in the maps, if you knob the idle down and it starts pinging/popping, your map is too lean, add some fuel to the map, and redo

[snrusnak]

Sounds like leaking intake seals. Is it worse when hot vs when cold?

[uly luigi]

yep, could be, ^^

[Stevenc150]

1st - Adjust idle as close to 950 as you can AFTER the bike is up to Operating temp.

-if still bad

2nd - Spray starter fluid around the intake seals with bike running. If idle jumps up, you have an intake leak.

-if still bad

3rd - Do a TPS reset and begin looking at your maps...

I'm betting you won't need to go past Step 1. ;)

[Carl0s]

Thanks, i guess i need to take a bit deeper look on the issue. Just tuned my maps doing ~30mile logging on low rpms, and then letted the Megalog do the trick...

Better, alot. Now the rpm drop only gets bit slower when the needle hits 2500, but atleast it doesent hang in there anymore.

The idle is that low?! I remember reading 1150 from somewhere... :/ Gotta adjust that, and thest the intake for leaks :)

[snrusnak]

Idle should be set to 1050. Do a TPS reset at proper temp and adjust the idle like you're supposed to. Then see if it's still doing it and see if the seals are leaking, there are a few ways to test that. I'd bet money that's the root of the issue though.

[spyder_monkey]

Just had the same problem this week after remapping and TPS reset. I re-adjusted the idle to just under 1000 (was 1050) and the problem resolved. Not sure if that will fix yours, but sounds similar and worth the easy shot.

[Stevenc150]

[confused] Snrusnak?? This has been discussed multiple times. The manuals idle recommendation is too high. 950 is sweet spot.

Do the simple stuff first. Twist the idle adjustment screw CCW a small bit after warm-up....simple. If no good, THEN proceed.

http://www.buellxb.com/buell_images/2339_20090602092410_L.jpg

[wolfo68]

if it starts hanging like that for no reason you can assume you have an intake leak.

[snrusnak]

Snrusnak?? This has been discussed multiple times. The manuals idle recommendation is too high. 950 is sweet spot.

I've never discussed this. I go by the manual, no reason not to(for me anyway), my bike runs great...

In either case, an idle that was set 100 rpm too high wouldn't cause a hanging idle, the idle rpm really doesn't have anything to do with rpm hanging.


if it starts hanging like that for no reason you can assume you have an intake leak.

Exactly.

[konarider94]

In either case, an idle that was set 100 rpm too high wouldn't cause a hanging idle, the idle rpm really doesn't have anything to do with rpm hanging.

a high idle will certainly cause a hang. bump up your idle to 1150 or 1200 and see if it doesnt hang. in my experience its a very fine line as to when it will hang on these bikes. im right at 1000-1050. If i get the idle up any higher it will hang on me.

Are the throttle cables adjusted properly? That may contribute.

I agree that leaking intake seals could be a possibility as well but like steven said try the easy idle adjust first.

[buellxb9rs]

Mine did that, and the velocity stack wasnt fully seated so I fixed that and did a tpa reset and it was fine. If it still does it after that then your throttle cable may be too tight or the pull cable too loose.

[eric_bloomer]

Same problem here. I adjusted the idle up since it was too low before. Around 750/800. Did it at running temp to as close to 1050 as I could. Now I'm getting the hanging idle too. Just adjusted it back down to 950 and I'll see if that helps.

[Stevenc150]

the idle rpm really doesn't have anything to do with rpm hanging.LOL...OK... [smirk]

[snrusnak]

You can laugh all you want, but your lowering the idle rpm to "fix" a hanging idle is a mask to the real problem.

How the hell would an idle set 100 rpm too high(which is actually the correct setting) cause a hanging idle?

Explain it to me if you know...oh you can't because there is no reason...

Even if you set the idle at 1,500 rpm it will quickly return to that rpm if the bike is operating correctly(no intake seal leak).

[ich]

yawn.
written already some thousand times: adjust spark advance.
issue fixed.

[Stevenc150]

How the hell would an idle set 100 rpm too high(which is actually the correct setting) cause a hanging idle? Technically I don't know, I just know it does....as Kona and 1000 others can attest to.


Explain it to me if you know...oh you can't because there is no reason...There's a reason, I just can't explain it. I just know its effects.


Even if you set the idle at 1,500 rpm it will quickly return to that rpm if the bike is operating correctly(no intake seal leak).Again, LOL, no it won't. Do like Kona said and try yours... I checked intake leaks & had none when my bike did it - simply turned down idle after reading the Forums & Voila! Go figure... That's why I always suggest trying idle first.

'Course it sounds like Ich may have the fix. Anyone going to try?

[snrusnak]

You are believing what you want to believe.

The idle adjustment screw is nothing more than a stopping point for the butterfly in the throttle body. It keeps the butterfly from closing completely, allowing a small amount of air to enter the engine.

When you are on the throttle and release it the butterfly closes nearly instantly closes to the point at which idle is set(stopping at the idle adjustment screw).

At this point the only amount of air allowed to enter the engine is the amount determined by the idle set screw. That is unless the air can enter somewhere else(such as a leaking intake seal). If there is no leak then the engine will immediately return to idle(whether it be 950 rpm, 1050 rpm, or 1500 rpm).

I also don't see how ignition timing(that is somewhat close to what it should be) could cause a hanging idle, but maybe ich can explain more on how this would be possible?

Also when testing for intake leaks be careful what you use, many sprays will ruin finish on the engine. Another method is to use propane, which won't hurt the finish.

[xoptimizedrsx]

Funny post.
1050 is a book number. not a problem. with the TPS at the 5.1 degree its a book number needed to get the somewhat area correct. However, with all bikes this will change to wear and environment. the 1050 was set at 1050 to pass emmissions at idle. a 900 up is 100% ok. look at the sportsters (same engine all idle at 950, all have TPS...)Hummm... made you think. Our engines is nothing more than a hopped up version.

Now to fix the issue. at idle look at your ego number if it is lower than 100 it is removing fuel and if higher it is adding fuel. locate the cell (One cell)== where your bike is during idle. adjust till you get ego 98 to 102 avg. its done. the fuel is now correct for your bike.

Now what rpm is it. if the tps is a frog hair to much it can allow extra air which will vent in the fuel mixture lean for a brief moment. which causes the hang. at the degree you have it will hand aprox 2000 then slowly drop. to fix it go back and drop tps degree to not allow the hang due to air flow. This en-turns lowers the idle speed. which when set correctly will be 975/1000.

Now how to do it.

2008 upon the throttle. you adjust your speed in the ecm.

2007 older in the program you have a reset tps on your ADX if you have my latest version in Tunerpro RT or Ecmspy. which ever you use.

First
back out the contact screw till the butterfly in closed. then open and close the throttle a few times to insure it is fully closed.

Second
click send on tunerpro Rt to send the reset command or reset on Ecmspy.

Third
now turn in till aprox 5.1% (do not reset AFV now)

Fourth
start the bike get it running ride it 15 mins till warm and the afv has learned for this days weather condition.

Fifth
return home or at shop. adjust tps till rpm is 975/1000 rpm. do not worry about what degree it is because the degree does not matter as long as its correct to zero and the setting matches your bikes needs.

This rest will make the entire ride more smooth doing it this way. It is not a mask nor incorrect. especially on bikes with aftermarket parts.

Example:
I personally have one bike that has a tps degree of 4.8 and another with 5.9 both idle at 950 rpm cause I like the lower rpm idle lope. the 5.9 degree bike if at 5.1 like the oem book states to use will not run. However. it has mods on it and head work. which requires more degree. Same for the other 4.8 degree bike the head work speeds up air making it use less.

I see stock setting from 4.8 to 5.9 to idle correct. its all in the location of the bike, wear and climate.

Now go check yours even if you dont reset it if you test ride it then tweak it to the version you will like it that one step more.

[xoptimizedrsx]

next issue to cover. your Idle rpm is timing based a stock older ecm has zeros at idle. which is incorrect from the OEM. once warm it faults to the zeros. Although, during warm up process you have tables to advance it. Once these are met you get the hang.

Now to fix it.

Open timing maps. Look at the lowest rpm and bottom two rows tps and first three rpm columns. On the front timing map set all six zeros to 9 and on rear set all to 6 or 7.

save new map.
Burn in new map.

Now it will idle smoother, however, the idle will increase and require a small amount less tps degree to get the 1050 if you desire to be that high. if already at 1050 it will go higher and need backed down a little. which now changes the air flow that was the initial problem in the first place. But by advancing timing it will allow the 1050 to be achieved. However, I recommend the 975/1000.

Therefore, you have two ways to fix it and both are correct fixes.

Dead horse beating Over. LOL

[snrusnak]

xopti, is what you're saying that when you close the throttle, the throttle(and tps sensor) might be open just a hair, allowing more air through? Then this extra air causes a lean condition until more fuel is added? This would give a high idle for a very short period of time, yes?

I don't believe that is his problem, as he says the idle stays at 2000 rpm and the only way to return it to normal is to let the clutch out.

As far as the idle rpm, doesn't really matter what you set it at, if you want it at 800, 900, 1000, 1100, or 1200 rpm's they should all work reasonably well, but lowering the idle rpm from 1050 to 950 rpm will not fix a hanging idle. There is another issue. Unless you explained something that I didn't see or understand...

[snrusnak]

I should say I'm not trying to say anyone is wrong, just that I don't think this is the issue and if it is I am missing something.

I just don't see how idle rpm effects an idle that won't return to normal(be it 950 or 1050 rpm shouldn't matter). If it was a slow returning idle I could see it but not if it stays at 2000 rpm.

[jazzn]

I don't know if it's the idle speed or not that is the real source of that problem. All I know is that I had the problem and I bumped the idle down to about 950 and the problem is gone, and the bike is behaving perfectly normally as far as I can tell. Starts on the first turn and idles normally even cold... and the problem is gone.

Good luck..

j.

[snrusnak]

^was your idle a slow return to 1000 rpm or did it "permanently" stay at 2000 rpm?

[jazzn]

Mine? Just stayed up there. Unless (same as Carlos) I would drag the clutch a bit with the brake on and it would go back down to normal. Then it would be back up to 2k at the next traffic light.

I just brought the idle down a bit and it stopped sticking at 2k. Never does it any more.

[snrusnak]

Ok well I guess my foot's in my mouth. Doesn't make sense to me though...

[ich]

there's the air path, and there's the spark advance path. learn which to walk.

[Stevenc150]

http://bgeiger.net/photos/main.php?g2_view=core.DownloadItem&g2_itemId=255&g2_serialNumber=2

[jazzn]

Doesn't make sense to me either.. fwiw. But at least I can stop worrying about it. We'll see if something new comes up.

[jazzn]

Doesn't make sense to me either.. fwiw. But at least I can stop worrying about it. We'll see if something new comes up.

Sorry about the double post. Not sure how i did that.

[lowkey]

Hey guys thanks for this info. I was on a ride yesterday with the wife and all was well through winding roads. Once we were out of the canyon and stopped at lights I got the 2k hang and could only get the rpm's to drop with the brake and let out clutch method. Once we got home I did a tps reset and the bike was fine in the garage. As soon as I left the house I was getting a 3k hang that wouldn't come down after the clutch drag, it would rise back up to 3k. I'm at work but will do what was posted, TPS reset with 950-1000rpm warm idle. I hope it works out, I thought it may be the TPS sensor going bad, clutch is adjusted perfect for sure.

[Theycallmecrash]

Has anyone monitored the TPS while this was happening? I might have had a hang yesterday but was there then not. Its possible the throttle blade has moved and the TPS voltage isnt correct for conditions. So moving the adjusting screw moves the blade to a happy spot for the TPS. Whats the proper procedure setting the idle!?! I might have just confused myself and made no sense.

[lowkey]

2007 xb12 RPM hang @ 3k starting this morning.

a 900 up RPM is 100% ok. look at the sportsters (same engine all idle at 950, all have TPS...)
Did this, bike is between 900-1000 RPM after zeroed out TPS reset.



Now to fix the issue. at idle look at your ego number if it is lower than 100 it is removing fuel and if higher it is adding fuel. locate the cell (One cell)== where your bike is during idle. adjust till you get ego 98 to 102 avg. its done. the fuel is now correct for your bike. The EGO number is a voltage% on ecmspy for me and reads between 0.00 and 0.60 at idle, Any help or info to get it to read as a number would be great!

[Theycallmecrash]

I believe the numbers are related to logging.

[lowkey]

I believe the numbers are related to logging. Thanks hopefully I can get that sorted but the bike is running great again with the idle set @ 900-1000. Rock solid with no rev hang so IDK if I should mess with it any further.

[mgrish]

I've got an 03 XB9S that I recently got back from HD. It had the fuel pump, ecm, and both injectors replaced. When warm it would "high idle" around 2500 RPM unless I lugged the engine and it would settle down to it's "normal" idle of about 1300 RPM. I turned the engine idle adjustment and set the new idle speed of about 1000 RPM and presto, my high idle problem is GONE! I was really worried that it might be an intake leak. This post gave me all the relevant info needed to solve the problem. My thanks to all that contributed!