Yellow Light Flashes Most of the Time

[RibEye]

I have an '03 Road King Classic. Have an appropriate TFI, a set of Hooker Tuned-Flow slip-ons (tuned for max flow) and a Screaming Stage 1 air intake.

Trying to tune to the TFI, and see that the yellow light takes a long time to stop flashing after start. When it stops flashing, I start to run up to fast idle to tune the green pot, and the yellow light starts flashing again. Again it takes a long time to stop flashing, and rasising the rpm again results in more yellow flashing. Sometimes just letting it idle and it starts flashing again...and so on.

Basically, what I see is yellow flashing most of the time. There is nothing in the user guide about this.

The ground connection is solid and the lack of red and green flashing tell me that the injector connections and signals are good. The electronic engineer in me suspects a cold solder joint inside the TFI (power supply?), resulting in resets due to vibration.

What do I need to know?

The TFI label has decided to fall off as well.

Enjoy,
Rich P

 

[BUBBIE]

I MAY be able to help here Before you get help From Dobecks.... being Sat and all...

It is normal for the yellow pot to blink but NOT as you say..

I would turn it down until it doesn't come on when EASY increase of the throttle RPM's..... If you Rap the throttle, it should come on... I also turned mine Down from the original setting....

The pro's will be along shortly....... I know that the setting should be set lower... Could be other reasons and they will Know!

Try it as it is easy to turn down and mine worked good after i lowered the setting, only com'n-on when hard twist of the throttle....

counter clock-wise to turn down..

signed....BUBBIE

 

[RibEye]

I MAY be able to help here Before you get help From Dobecks.... being Sat and all...

It is normal for the yellow pot to blink but NOT as you say..

I would turn it down until it doesn't come on when EASY increase of the throttle RPM's..... If you Rap the throttle, it should come on... I also turned mine Down from the original setting....

The pro's will be along shortly....... I know that the setting should be set lower... Could be other reasons and they will Know!

Try it as it is easy to turn down and mine worked good after i lowered the setting, only com'n-on when hard twist of the throttle....

counter clock-wise to turn down..

signed....BUBBIE

The flashing is not in response to engine speed. It is the kind of repetitive flashing you get during TFI initialization. My setting is at around 3:00, already lower than starting point in the manual. Varying it does not affect the flashing.

Nice shot though.

Gas mileage is not very good either. Engine runs. Just TFI yellow flashing indicates it is not running as it could.

Enjoy,
Rich P

 

[BUBBIE]

The flashing is not in response to engine speed. It is the kind of repetitive flashing you get during TFI initialization. My setting is at around 3:00, already lower than starting point in the manual. Varying it does not affect the flashing.

Nice shot though.

Gas mileage is not very good either. Engine runs. Just TFI yellow flashing indicates it is not running as it could.

Enjoy,
Rich P

If you turn it down all the way IT should Not flash.

Increasing the pot from OFF should allow you to set it so it Doesn't flash after initializing has been completed (several seconds of running at idle)

If you are turning pot 2 down and it still Blinks when lower than 1..... Yes definitely something is wrong.

The setting on mine wound up below 2.5 setting and was suggested at 3.25..

After the engine starts and the initializing is complete, it should idle at NO yellow com'n on.

The yellow pot is putting way too much gas in as you know... It is doing the same as moving the accelerator pump up and down when it should not.

signed....BUBBIE

 

[RibEye]

Update:

She runs real sweet when fresh and cold. I don't know about the TFI lights. I have not had access during these times. She might run real nice for quite a while.

Intermittently, when warmed up, she will begin to run ragged, stutter in low gears at low rpms, and cough when starting off from a stop. I just had a mpg reading of 23mpg on one tank of gas (not good, and seems to do only around 28 in town, also not good).

I checked the TFI indications when I got home, last time it happened. I turned her off and opened up the TFI. When 1st started, the green and red lights flash for a bit (10 secs or so), as well as the yellow. Then the green goes to steady on and red to steady off, but the yellow continues to flash. After a long period of flashing the yellow stops flashing for a bit, then the green flashes out and back on (single blip), I hear something in the idle, and the yellow starts flashing again, and so on. Periodically, while idling, the red will flash on and off very briefly (single blip).

If I rev it while the yellow is not flashing, I will get the green drop-out and the yellow starts flashing again.

Taking the yellow pot all the way counterclockwise has no effect on the flashing. But increasing the rpm, with yellow pot set back to around 3, does seem to bump the yellow flashing rate a bit. Letting her go back to idle drops the flashing rate back down. The yellow flashing is regular, not irregular.

I'm not sure it is the TFI, but I do not know enough about how it works to diagnose its behavior. I'm thinking I may have a problem with the crank position sensor getting weak and maybe near to quitting. I am not sure, but, I do know that I have a full stage 1 installed and can't just take the TFI out. The scooter will go way lean. I think I'll replace the crank position sensor, since it seems that timing and fuel mix are affected. If that does not do it, I'll have to take the TFI out, put the original air box back on and see what happens, but boy what a pain.

I'm afraid the dealer will point at the TFI no matter what the cause is, unless it is not connected. So, If I take it in for diagnoses, the TFI may have to come out (and original air box back on). If I do that, I'm gonna have the stage-1 download done, so I don't have to put the original airbox on if TFI is removed ever again.

I am an electronics engineer (30 years experience), so I can grasp technical concepts, software and hardware. I'm not asking for proprietary info, just enough to help me diagnose the problems I am having. I've owned the TFI for just shy of a year.

I want the fuel tuning supplied by the TFI. If I have to replace the TFI, I'll go with the Gen-3.

Enjoy,
Rich P

 

[DobeckTechSupport]

Ribeye,

We'll post some information here to help out spreading some knowledge to all the forum members, but we would like to speak to you on the phone to help run some tests to determine your problem and tune your bike.

Very important information to take note because some previous posts were wrong.

1). For the TFI there is NO YELLOW FUEL SENSITIVITY ADJUSTMENT. The GEN 3 and beyond controllers added this, but the TFI does not have this. You should not have to be adjusting the RPM POT at all.

2). Fuel is only affected by a zone WHEN A SOLID COLORED LIGHT IS DISPLAYED. The yellow light flickering can be normal in some circumstances, but does not mean the Yellow zone is active.

In regards to your thoughts about the crank position sensor going out, are you having a hard time starting the bike? If you're not having starting problems then highly unlikely the sensor is a problem.

Term to define here to help understand the yellow light flickering is ASYMMETRICAL PULSES. You would think at a steady idle and not touching the throttle that the injector pulse width would be symmetric right? Wrong!! The injector signal at times can jump to a strange input and then back to normal. All piggy-back controllers have to implement an averaging system to help deal with these pulses.

High concern from your posts is your fuel mileage. Something has to be wrong here because that is definitely way too low. We would ask you to post your settings here where at least at "fresh and cold" you like the way your bike is running.

 

[RibEye]

Ribeye,

We'll post some information here to help out spreading some knowledge to all the forum members, but we would like to speak to you on the phone to help run some tests to determine your problem and tune your bike.

Very important information to take note because some previous posts were wrong.

1). For the TFI there is NO YELLOW FUEL SENSITIVITY ADJUSTMENT. The GEN 3 and beyond controllers added this, but the TFI does not have this. You should not have to be adjusting the RPM POT at all.

2). Fuel is only affected by a zone WHEN A SOLID COLORED LIGHT IS DISPLAYED. The yellow light flickering can be normal in some circumstances, but does not mean the Yellow zone is active.

In regards to your thoughts about the crank position sensor going out, are you having a hard time starting the bike? If you're not having starting problems then highly unlikely the sensor is a problem.

Term to define here to help understand the yellow light flickering is ASYMMETRICAL PULSES. You would think at a steady idle and not touching the throttle that the injector pulse width would be symmetric right? Wrong!! The injector signal at times can jump to a strange input and then back to normal. All piggy-back controllers have to implement an averaging system to help deal with these pulses.

High concern from your posts is your fuel mileage. Something has to be wrong here because that is definitely way too low. We would ask you to post your settings here where at least at "fresh and cold" you like the way your bike is running.

Thank you for your responses. At this time, I have settled on the following settings:

Green: 2.5
Yellow: 2.5
Green: 3.5
RPM: 4.0

The ragged running is subtle, not major. The missing is not real big, just noticeable. The 23 mpg reading was a single event, and I may have had a part in twisting it during that time. Generally, the mileage is consistently around 28 in the city (a bit low in my opinion). I did just have a 43 mpg highway run, over the weekend (highest since pinhole in fuel line repaired, and TFI and SE air box installed), but the subtle ragged running, missing, and coughing off of stop, occurred at the end of the day. The missing is evident during idle or right between coast and power, in low gears.

I have purchased the CKP (crank position sensor), and will install it sometime soon. I have a couple of runs in the near term and don't want to risk the scooter being down, since I am leading. I'll post back whatever I see, after replacing the sensor. I have read several threads describing similar symptoms, caused by bad but not inop CKP sensors. I have had a single "difficult to start" event, but that may be a simple anomaly. Normally, the scooter fires right up. Prior to fixing the pinhole in the fuel line, it was normal to take 3-4 tries before it would fire up. Now it is usually fires up right off. I have not checked the current CKP sensor for metalic fuzz, but I do not expect find any when I do.

Enjoy,
Rich P

 

[RibEye]

I believe I have found the cause for my engine performance issues (all subtle, not bad, just fairly noticeable):

• Intermittent ragged running, with commensurate ragged exhaust note
• Excessive decel popping
• Intermittent bucking and surging at low rpms and speed
• Chirping left rear muffler mount
• Hesitation, coughing and stuttering from stop when fully warmed up

Loose connection between the head pipe and head, on the rear cyclinder, resulting in an exhaust leak. Tightened her up and all the listed issues disappeared. She purrs like a kitten now. I have not checked the effect on the TFI indicators, but I will check that, and attempt a retune, for optimum, early next week. I'll post back here with what I see.

(PS...I have not replaced the CKP sensor. The new one is in my parts collection in case I ever need one)

Enjoy,
Rich P

 

[Hoople]

I believe I have found the cause for my engine performance issues

Rich, Were the studs in the heads tight? How much did you have to tighten the nuts. Was it just a couple of flats to get them tight? You did not have to replace the exhaust gaskets?

 

[RibEye]

Just over a 1/2-turn, and did not replace the gaskets. I'll replace those when I do my cams and tensioners...month or 2. Just want to enjoy riding for a bit...

Enjoy,
Rich P