Revs wont drop to idle

[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]

 

[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!