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Discussion Starter · #1 ·
I just bought a 03 Roadking Classic EFI 17000mi. Stock Air box, Vance and Hines basic slip ons. Bike starts up fine. Plugs a little on the white side. Problem is, at low speed cruise 0% to 10% throttle or and thing under 35 mph, no load, the bike seems to surge or sputter as if it is starving for fuel or spark. If it is under a load its fine, cruising speed its okay. Also seems like idle is spratic. Runs up the RPM okay. Any ideas? This is my first Harley and I love the bike. Thanks in advance for your input.
 

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Low speed stumbling.

It sounds like it's running lean. Even though you're only doing pipes at this time, it's still lean. My '02 RKC did the same thing with pipes, A/C, and a Stage 1. I put a DFO into it and it's just about completely gone.

If you're going to get rid of that stumble, you'll need to do something to add more fuel. It could be Stage 1(will probably not be enough), DFO/TFI, SERT, Power Commander, or some other method of adding fuel. While you're at it, do the air cleaner too. There are threads all over on what to do in these areas.

By the way, the seat of the pants dyno will know the difference and your bike will actually sound "deeper".

Tim
 

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Discussion Starter · #3 ·
I was hoping not to do a PC or a SERT,.. ect. I am tired of tuning bikes. I will deffinatly start with the Stage 1 map and A/C. Reason I dont want a PC or SERT is that it is just to tempting to start tinkering. I get to the point were I want perfection and sometimes stress myself over it. I want to relax. Thanks for the info.
 

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Discussion Starter · #4 ·
Well I went and did the Stage 1 down load and Screaming Eagle air kit. It does run better but you were right. It did not eleviate all the issues. I went ahead and ordered a PCIII USB tonight and will give it a try. I have read good things about them. Plus side is Power Commander already has a map built for my exact setup. One other question. Would getting the Vance & Hines true duals to go with my slip on mufflers help performance any?
 

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From what I've seen on dyno sheets and my own personal experience, the true duals do not help performance as far as peak numbers, expecially when going to big bores and radical cams. But I've seen some sheets show a true dual setup start its torque curve higher than the two into one systems from 2K-3K rpms. The duals also tend to relieve some of the popping on baggers with high flow slip-ons.

Since you're getting a PCIII, you should probably go to a good tuner (research required!) and follow some of his recommendations for your setup. If you can't find a decent tuner, you might want to stick with a setup that matches some of the canned maps for the PCIII. They're usually only starting points, some tweaking might be required. All depends on what you want from your ride. :D
 

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Discussion Starter · #6 ·
I just want the bike to breath the way it should. I dont mind losing a few mpg to achieve it. To me, it seems that most mechanical issues arrive from the bike being to lean and putting unessesary were ant tear on the motor from running to hot. I am also not looking for the 100% perfect tune. Just a stock motor with hi flow intake anf pipes to run far better than the way in came from the factory.
 

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There is a better than even chance that your TPS is out of whack. If the unit is not calibrated for 0% throttle position when fully closed (voltage readings should be between .35 to .45 millivolts with switch on and engine off) then the ECU will not be in idle mode and......well you know what happens. It also throws the rest of the map off as now when you are supposed to be reading certain fuel supply in certain RPM range you are off a column or two from where you are supposed to be. Another reason for this condition is that the TPS has gotten "noisy" and puts out a varying voltage signal that the ECU cannot get a handle on and other sensors go a little squirrely getting contradicting input. Don't bother throwing fuel changes at this thing until you are calibrated out or you will simply be adding changes that will have you farther away from where you should be when you get zeroed out.
 

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Discussion Starter · #8 ·
Tps

GROCK

How do I check the TPS. Can it be done with a multimeter? Im no stranger to electronics I have a degree in electronics from DeVry. I think you are on the money on my issue. I connected my laptop to the powercommander and with the bike not running it shows the idle position varying up and down. You would think with the bike not running it would remain stable. If the TPS is bad, can I just bolt a new on in to correct the issue? Any info would be gre
 

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The cheapest way is to swap it out. The dealer will charge you three times the cost of a new one to calibrate your old one and probably still get it wrong. When you put in the new, if it is steady reading but out of range, let me know and I'll tell you how to get it zeroed out with the map.
 

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Part Number?

GRock said:
The cheapest way is to swap it out. The dealer will charge you three times the cost of a new one to calibrate your old one and probably still get it wrong. When you put in the new, if it is steady reading but out of range, let me know and I'll tell you how to get it zeroed out with the map.
That's the info I was looking for Rock, thanks. Any idea what the part number is for zzmellio's ride and for an '04RK?
 

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Discussion Starter · #11 · (Edited)
Tps

Strange thing just happened. While the bike was running I unplugged the TPS connector. Bike stumbled but kept running. I then pluged it back in and the RPM picked up and it idled out smoth. RPM's fluctuated between 1100+/- 15 rpm's. I wonder if the TPS just had a bad connection to the plug? I will monitor it. PCIII is a cool unit. While the bike was running I have added and subtracted fuel to the idle rmp range and can tell a noticable difference in the bikes idle.

Thanks to everyone who is helping me out. Beats talking to a stealer. All they want is for you to bring the bike in.
 

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Throttle Position Sensor Change

Was having trouble with intermittent low idle when bike is at normal operating temp. Shutting down and restarting sometimes cured the problem. Others have posted similar problems. Grock wisely diagnosed this issue (thanks Grock) as the TPS being out of calibration, thus sending bad mojo to the Idle Air Control (IAC).

Without the equipment and electrical manual, the only way to get it calibrated was to take it to the dealer or a knowledgeable indy. Both propositions are a little dicey considering proficiency levels around here. The dealer option would be an hour at $75 (at best), and the results would not be guaranteed.

Picked up a new TPS for $36 and installed it. Installation was about 30 minutes and a .2 on a scale of 1-10 in difficulty. Bike now idles smoother (not my imagination, it really does) cold and warm. No difference that I can tell riding, so the new TPS does not seem to affect the fuel delivery as related to fuel mapping. Have Delphi TB on an '04 RK, and P/N is 27629-01. Part number for MM is 27271-95. Magnetti-Marelli makes both of them.
 

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did a search on this topic -- sorry for the year old thread revisited but, this is exactly what my '04 diagnostics code keeps showing-- throttle position sensor open/low. Of course the bike does a "lag" a bit at idle but it picks right up when I give it some gas. Where is this TPS located? I want to check and clean the electrical connections before getting a new one. TYVM.

Edit; Also I saw a post by MR. "G"Rock about correct electrical range .35-.45 millivolts and a 1/4 to 1/3 turn of the throttle blade can fix it if it's in the upper end of the voltage range (turn it out).

Grock--can lizard juice be used to clean electrical connections?
 

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took of the air cleaner/housing and disconnected plug ins. cleaned everything up. clear all codes and got "NO rSP for the TPS. Ran it the bike and still have the sputter at low idle-and starting from a stop.

Don't think the throttle blade adjustment is the way to go just because of the consistent diag codes I get after clearing them and then running the bike. So. My question is, since the install of a new TPS is pretty straight foward and like mikie said a .2 on a 1-10 scale, I see that there is a voltage check (which I haven't done yet)--where is this done--at the TPS? or somewhere else?

Second question--does a new TPS need to be calibrated or is it install and ride? TYVM
 
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