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Buell Motorcycle Forum » XBoard » Buell XBoard Archives » Archive through September 19, 2006 » Surge in RPM when warmed up at idle « Previous Next »

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Tgroghan
Posted on Monday, September 11, 2006 - 07:12 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Got the bike up to operating temps and let it idle. It surges RPM. I hooked it up to the VDSTS and recorded what it was doing, but I don't know how to analyse it from there. There were not trouble codes. Where do I go from here?

Background info.
2004 XB12R, race ecm, race muffler, k&N filter

Performed TPS reset and AFV reset prior to below work. When work below was performed everything looked good; seals, wires and plugs. It acted like this before the work was done to it and still now after the work.

Recent work done: new intake seals, new wires and new plugs.
5,000 miles on bike.

TPS voltage is set at 6.5 right now.
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Samiam
Posted on Monday, September 11, 2006 - 07:27 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

What's your idle speed set at (before it surges)?

Sam
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Tgroghan
Posted on Monday, September 11, 2006 - 07:51 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

It was running 1050-1100 rpm during the longer duration of time before it would surge, when I recorded it during this test. It surged from 825 - 1625 rpm regularly.

It also ran bad when the engine speed was set below 1000 rpm.

I ran the test again, just now, at a lower TPS value at idle of 6.0v which was running under 1000 rpm. It did the same thing, surged. I then increased the rpm with the hand throttle to a TPS value of 7.1v. The surges were more pronounced and extreme in RPM variation.

(Message edited by tgroghan on September 11, 2006)
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Hammer71
Posted on Monday, September 11, 2006 - 08:42 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Have no idea if you have tried or how you reset your TPS but try this.. Hook up VDSTS and reset TPS, when doing this though back the idle screw out to zero or as close as you can get .. dont back it out any further than that. Then reset, set idle to the prescribed rpm range and it should clear you up. I had the same issue and couldnt figure it out. After trying the reset this way I have no issues and it has actually cleared up a few local riders issues as well.
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Davo
Posted on Monday, September 11, 2006 - 09:12 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Check all of your grounds twice!
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Tgroghan
Posted on Monday, September 11, 2006 - 09:42 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

When I've done the TPS reset I back the screw out to zero and a lot more past that. I have not tried it at exactly zero. I will try that though.

After that I will look over the grounds.
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Davo
Posted on Monday, September 11, 2006 - 09:53 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

You did it right if you went past zero. The purpose of going further is simply to make sure that the plate is completely closed prior to the TPS reset. I think there is another problem. Check electrical connections, especially grounds and battery cables. Try to pull the codes manually. There are some codes that are not in VDSTS!
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Tgroghan
Posted on Monday, September 11, 2006 - 10:29 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Davo, I think you are correct, something electrical. I tried the TPS reset this other way and it didn't help.

Did the manual retrieval of codes, per instructions on here: http://www.badweatherbikers.com/buell/messages/32777/146574.html, and nothing came up, just rapid flashing of the light. I will ride it tomorrow and see what it yields after that.

Now it is a 2004 and this is 2006, which means the battery is 2 years old or there abouts. I have a load tester that I could check that with but I'd not think it would be so simple as to a battery that still had 12 plus volts on it.

(Message edited by tgroghan on September 11, 2006)
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Davo
Posted on Monday, September 11, 2006 - 10:41 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Correct, pin one and two. If you are looking at the connector with the locking tab down, then 1 and 2 are on your left. Jump across them and then turn on the key and ignition. Do not start the engine. A series of about 10 or so fast flashes indicates intermission or no codes. Then turn every thing off and remove the jumper.
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Tgroghan
Posted on Tuesday, September 12, 2006 - 07:25 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Had a hack of a time keeping the bike running this morning before taking it out. I set out on my morning commute, highway, and it did fine. The bike ran better when I got off the interestate (the computer learned something during that time) at warm up temperatures at idle.

The idle was a little high about 1200 so I dropped it down to 1000 rpm. No error codes were present when I checked it after my commute. The bike idles warm fine right now, but the rpms hover (when I open the throttle and close it fast the rpm stays high then comes down slowly) even being set at 1000 rpm. Right before I stopped to get off the bike I was in traffic and it would hick-up from stop to go. It is not smooth at all when at low speed in a low gear.

I'll see how difficult it is to keep running this afternoon when it cools down.
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Aeholton
Posted on Tuesday, September 12, 2006 - 08:35 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Tgroghan - It still sounds as if you did not reset the TPS properly. Please confirm that you are not using VDSTS to "reset" until after you back your idle adjustment screw out. Then snap the throttle a open and fully closed. Use the VDSTS to reset TPS. After the reset turn idle screw in to TPS reading of 5.1. Start the bike (do not touch the throttle) and allow it to warm up to 320F. Only after it is warm adjust the idle to 1050 rpm. If you skip the warm-up, it will cause problems like you are experiencing (don't ask me how I know).

Also, make sure bike is fully "ambient cold" when you start the process.
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Tgroghan
Posted on Tuesday, September 12, 2006 - 11:23 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I perform the TPS reset just as you wrote. Back the idle adjust screw all the way out and then some. Reset TPS and AFV. Reset idle screw to 5.5. I check the throttle voltage as well making sure it is w/in spec.

I have the TPS set to 5.5 when I restart the bike and even then it dies several times. At 5.5 reading the bike idles about 800 rpm.

I've performed numerous resets using VDSTS program following Als guidance found on Badweb.

I was under the impression that a TPS reset could be done when the bike was warm too. Am I wrong on that one? I've done resets on warm bikes and on cold ones.
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Davo
Posted on Tuesday, September 12, 2006 - 11:41 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Warm idle TPS has to be about 6.2 for 1150 on my Uly.

If you can't find loose electrical contacts my next check would be to run injector test and coil test. If they pass and they should then I would look for an intake man. leak. A periodic short to ground from the coil or secondary wire (plug wire) off the #2 cylinder will make #1 go lean. Surging could result. Manifold vacuum is high at idle. Use propane as the manual states or I have found WD 40 works too with the small applicator tip.
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The_new_guy
Posted on Tuesday, September 12, 2006 - 12:15 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

"I perform the TPS reset just as you wrote. Back the idle adjust screw all the way out and then some."

I found out that you have to be careful with the "and then some". I backed my idle screw out until it completely unthreaded at the throttle body. Not too hard to fix but a pain anyway.

Gregg
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Tgroghan
Posted on Tuesday, September 12, 2006 - 12:20 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I too thought manifold leak that is why I just did, last week, replaced the manifold seals. I'll put it on the "something to check again" list. Yes, 6.2 did seem to be around 1150 as I was working on the bike.

If there was a short in coil area would show on the VDSTS while running giving one cylinder more spark advance than the other correct? Both cylinder were giving the same numbers when it would surge.

Yippie, I will check the wires.

On another Buell XB I ran into a problem with the plug wire grounding out, that problem showed up on the VDSTS as one cylinder getting more or less spark advance than the other. I think it also had an intake leak.
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Tgroghan
Posted on Tuesday, September 12, 2006 - 12:23 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Yes, "and then some" was not more than one more 360 degree turn of the idle screw.

When I was in there changing the plugs, wires, and intake seals I noticed how tight it was in there compared to the XB9. The larger diameter intake fills the V between the cylinders.
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Davo
Posted on Tuesday, September 12, 2006 - 01:38 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

A short should not necessarily change the advance. Use the "Active test" feature on VDSTS to check your components. Check with key and ignition on and engine off! See if they pass. Are you bone stock?
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Tgroghan
Posted on Tuesday, September 12, 2006 - 01:47 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Only upgrades to the bike are the race kit, nothing else. I'll run the active tests.
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Blake
Posted on Wednesday, September 13, 2006 - 01:12 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Don't set idle at 5.5 V on TPS. Set the idle at 1050-1150 rpm and check to see if the TPS voltage is within the specified range. Make sure the throttle is snapped closed when you do the TPS rezero. If you just back the idle screw out without snapping the throttle closed, you may not obtain a good TPS rezero.
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Tgroghan
Posted on Wednesday, September 13, 2006 - 10:22 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Started the bike to go home yesterday and it start and idled good (smoother than before) without stopping. It ran better than before (due to learning of the computer my guess). Now the rain is here for a day or two.

Yes, I always snap the throttle to make sure it is shut, as Al perscribed doing in his write up of the VDSTS and TPS rezeroing.

I'll update when I find out more.
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Davo
Posted on Wednesday, September 13, 2006 - 11:16 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Tgroghan,

If you think the AFV needs to recalibrate to the new ECM then go for a ride. You need to cruise at about 55 mph in 5th gear and do not decel or load the engine for about 3-5 minutes. This will give you a very conservative AFV. If you still have problems then it is something else.

(Message edited by davo on September 13, 2006)
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Tgroghan
Posted on Monday, September 18, 2006 - 09:03 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

After I reset all the stuff last week and ran it in 5th for 5 min(est) it has now done much better. It fired up and idled well this morning, and ran well on the way in too.

After changing all those components (intake seals, plugs and wires) it needed a TPS rezeroing and AFV reset.

IF it comes up again I'll be sure to ask.
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