Poor Throttle Response on Roll On

Discussion in 'Engine, Fuel and Exhaust' started by wb4eje, Oct 11, 2010.

  1. wb4eje

    wb4eje Member

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    I traded my '05 Electra Glide Classic for an new '08 Ultra Classic. The '05 had a SE Air Filter and a set of generic glass packed mufflers and I tuned with a SERT and it ran great, got 45-50 MPG in back road cruising, good power, excellent throttle response. Likewise I installed the SE Air Filter and a set of SE (catalyst) and tuned the new '08 with a SE Pro Super Tuner. Again, it ran good, gas mileage is not as good as the old '05, but it was OK.

    One day while cruising the North Georgia mountains I noticed a problem with the throttle response. After backing off the throttle going downhill and rolling back on (as smoothly as possible) the power didn't come back on smoothly. It was like a lean surge as the power would come back on. At times the power comes back on sharply enough to clunk the driveline. I hadn't noticed this in six months of riding, but suddenly it was there.

    I felt like it was a hardware related problem. After I started getting some codes (P1511 and P2102) I took it to the dealer. They gave me standard response number 1 - "they all do that." The second trip I got the - "we didn't find a problem" response. I took it to another dealer who acknowledged that there were codes and it did surge, but they didn't know what was wrong with it. They suggested that I "ride it till it breaks and bring it back." Yeah, right!

    I put the SEPST on it and collected some data. I really couldn't see anything out of the normal in the data recording, but since the SEPST doesn't have the ability to record true AF ratio only desired AF, I hooked up my Innovate LM-1 Fuel Air meter to the bike, and also captured voltages from the MAP sensor, the Twist Grip Sensor, and the Throttle Position Sensor feedback to the ECM. It wasn't a lean surge, the air-fuel was just about right on with the data from the ECM.

    The codes persisted to pop up from time to time. I cleared them and rode on, still surging when you roll on the throttle. That's when noticed that here is no surge if I am using the cruise control. Seems the ECM can control the throttle position but the Twist Grip did not. So I replaced the Twist Grip Sensor and the throttle body just to be sure. No difference. So now I am thinking it is a software problem in the throttle control of the ECM.

    The bike is out of warranty now, so no more visits to the dealer unless I give them money to "diagnose" the problem. They tried that, under warranty, I don't think they will have any better luck if I pay them.
    Anybody got any ideas?
     
  2. Hoople

    Hoople Account Removed

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    I don't know what the dealership needs for them not to say "they all do it". The bike has a pair of codes that are in a printed Service Bulletin from the MoCo.. Do they need the ECM to reach out and shake them by the shoulders. Amazing.

    It's caused by "fretting" (micro-motion) of the twin pots on the twist grip.
     
  3. wb4eje

    wb4eje Member

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    Hoople,

    Yeah, I thought so too. I saw the TT418 and checked that out. Wasn't it! Wish it was as it was a pretty easy fix. TT418 was regarding the Throttle Control. While I was changing the Twist Grip Sensor I also check the pins with an eye loupe and they were clean and shiny. No fretting at all.

    TT418: DTCs P2135 and P2101 Theory and Diagnostics - Harley Davidson Community
     
  4. Hoople

    Hoople Account Removed

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    The P1511 code is the result of the P2102. Fix the 2102 and the 1511 will also go away..
    The dealership did not inspect, remove or replace the Throttle actuator control motor/ feedback circuit or the Feedback pots? Assuming it is not a software issue, it really can't be too much other than the feedback servo motor pots or the throttle body motor itself. Sure, it could be the driver circuits in the ECM but that would be very remote in my eyes. A number of members have had that code come up. but they either live with it or never get back with what actually fixed it.

    I myself could not live with it. My guess would 1st be feed back pots on the throttle body not matching so the ECM immediately goes in limp mode. Next on the hit list would be the servo motor itself.

    I believe there was also an engineering change from Tin contacts/pins to flashed Gold pins and contacts on the twist grip. That won't be the reason for the P2102 but it's something to think about. Micro-motion fretting is something all contacts are subjected to.
     
  5. wb4eje

    wb4eje Member

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    I don't know what the dealers actually did. You aren't allowed to talk to the techs, and the service writers don't have a clue. So I have no idea what they did to diagnose the problem.

    I have thought about the fact that it could be a bad ECM module. (Don't like to think about the cost of replacing that! Would be cheaper to buy a GoldWing!) I will hook up my LM-1 to the servo motor in the throttle body and see what the voltages look like. I will have to build a small voltage divider to scale the servo motor voltage down to 5 v full scale for the LM-1, but that is no problem.

    I've used the LM-1 (has 5 channels of 0-5 Volt analog input that you can log data with while riding) to monitor the actual voltages from both circuits of the Twist Grip Sensor and the Throttle Position Sensor and I don't see anything that looks bad.

    I'm about fed up with this problem. The bike runs great if you don't have to come off the throttle and back on. But that can be quite an aggravation riding up in the mountains where we like to ride.

    Thanks!
     
  6. Hoople

    Hoople Account Removed

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    I can relate to the frustration you are experiencing. Not with TBW on Harley but TBW in general. In most cases, the firmware is written not to allow the butterfly in the throttle body to follow what your hand (or foot if a cage) is actually doing. Also not being able to talk to the tech leaves a lot of unanswered questions.

    Regarding the error codes,,,I really don't think it is the ECM in a strict Hardware sense. The firmware may have a few loose screws in it but I would bet the "Hardware" in the pure sense of the word is OK.

    I don't have TBW on my ride or a parts manual for your year bike but if the throttle servo motor and feed-back pots are sold as 1 unit & as 1 part number, I just might try that if it was not too expensive. A flat spot on either pot would raise havoc with the ECM.

    At least the problem is severe enough for the ECM to recognize something is wrong and log an error code. That is a very Positive point & makes it a workable problem. It's got to be something with your servo motor & feedback control that is just not right. I bet the summing voltage off the two pots is not consistent, or the connector to the twin pots mounted at the throttle Body is pitted from micro-motion. That's the first place I would look at and start at.

    Make sure when using the Innovate that the sampling rate is fast enough and a glitch will be captured. (I never used one so I don't know how good they are at glitch capture).
    I have one of their G2 standalone wide-band Air/Fuel ratio meter/controllers that works pretty good. I have not have much luck using their Patented tail pipe holder because of exhaust flow reversion. But it Works Great at a bung port closer to the cylinder head! :)

    This won't help with the error codes but as far as the "feel" of the twist grip and response of the engine, you may want to take a peek at the "Throttle Progressity" menu in the SEST software.
    In some cases/RPM bands the butterfly has been software clamped.
    Example: At 1000 RPM, a twist grip of 100% WOT throttle, only yields a 23% of open butterfly. I myself could not live with that. If I owned TBW I would have to make ALL ratios 1:1.

    They are trying to protect people from lugging there engines. I understand where they are coming from but I would Not need the Moco protecting me from myself. :p
     
  7. wb4eje

    wb4eje Member

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    Hoople,

    My old version of the Super Tuner software does not have the ability to modify the throttle by wire map. I have ordered the 2010 version of the software which does have that function. That should be here next week and maybe I can Tweek the stumble out of it.

    I asked the dealer parts counter guy if the 2010 software was compatible with my older (2008 vintage) hardware. He looked at me just like my Dashound does when I talk to him.....kinda tilts his head and looks at you like "What?" Anyway, they didn't know so I had to call customer support. They didn't know either, but eventually got a tech that thinks it is compatible! We'll see......update next week.
     
  8. wb4eje

    wb4eje Member

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    Update - Last Friday I received the 2010 version of the Super Tuner software. Loaded it on my netbook, updated, and pulled the basically the same tune I started with on the 2008 version as my base. I used Smart Tune to update the VE tables, then loaded the same Spark Advance table that I had with the 2008 version. (The VE tables from Smart Tune were very close to what I had created before)

    I test rode the bike and the poor throttle response was gone! Woo-whoo! However, after a bit more riding I found that it wasn't actually gone, it moved down to about 1500 RPM. At this point the only real difference in the map I was running and the previous one was the fact that the 2010 version of the software has a map for Throttle Progressivity. I have adjusted the throttle progressivity and also added a bit of fuel at 1500 RPM and the poor throttle response is just about gone. I think a bit more tweaking of the maps I will have it completely gone.

    I am going to do a few more runs with the Smart Tune to further refine the VE tables and see how it runs. But right now it is decent, but not perfect.

    Thanks for the all the suggestions!

    Bob
    Woodstock, GA
     
  9. Hoople

    Hoople Account Removed

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    Where exactly where is the throttle bog. Does the bog happen just when coming off idle or coming off Zero throttle position.
     
  10. BUBBIE

    BUBBIE Well-Known Member

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    I'm sending out a PM to locate This Thread OP and find their answer... Hoople tried to continue this Thread and Answers would be great to see here...

    Thanks Pete for the link to HELP the OP that has the very same problem on the forum Now...

    I still think it to be the Motor on the intake manifold (09) as Replacing Mine SOLVED MY Problem....

    signed....BUBBIE

    ANYBODY know this member ? Contact him.

    wb4eje
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