start with 1 cylinder, then the other

[fin_676]

I do not understand what this means => "Stroboscopic lamp plugged on rear spark-plug cable lights up well since motor start"

Strobascopic lamp or stobe light or timing lamp is a lamp used for setting dynamic ignition timing each pulse of fire from the coil will induce a flash from the lamp normally connected between the plug cap and plug or has a sensor that is hooked over the high tension lead it is powerd from a 12v source often the vehicle battery and as such produces a pulse of light with every pulse to the spark plug
IE if it flashes the plug is sparking

Brian

 

[roadking01]

The rear cylinders seems to produce no explosion as the exhaust pipe remains cold more than 5 seconds compared to the front pipe.


When you say the exhaust pipe remains cold more than 5 seconds compared to the front. where on the rear pipe do you feel for warmth right at the head or closer to the muffler?

 

[Hoople]

If I understand you correctly you still have a rear cylinder failing for 5 seconds after a cold start. At least part of this failure must be electrical by proof of Both using a strobe timing light and pulling the plug and not seeing a spark jump for the 1st 5 seconds after you start a cold engine. You have changed BOTH spark plugs with NEW and the results have not changed.

So you are NOT seeing a spark jump across the plug and the timing light strobe is not flashing for the 1st 5 seconds of run time on a cold engine. That issue needs to be addressed. If I was dealing with a similar issue on my bike I would first check all the easy low cost possibilities.

Unplug and inspect the low voltage 4 pin connector going to the coil. Be sure that the 4 pins are clean. Do NOT use anything like WD40 on any electrical connectors. Use Nyogel 760G (HD #99861-02). Removed BOTH high tension wires coming out of the coil and inspect the inside of the coil tower for corrosion or carbon tracking. At least check the resistance of each spark plug wire. Post what the measured resistance is of each plug wire. I would also unplug and inspect the large multi-pin connector going to the ECM. An unplug, inspection and re-seat of that connector is a Must at this point. Use Nyogel 760G.

If the above does not buy you anything, it is now time to determine if the failure is coming from the ECM or something other than the ECM. Would the 4 wires going to your coil pack happen to be yellow/green,, gray/blue,,yellow/blue,,blue/orange. If not what colors are they.

The only service manuals I have are for my 2009 FXDL so I can not tell you what the resistance table (ohms vs temperature) is for your Cylinder head temperature sensor. Are you working with a genuine HD manual for your year bike & model. Do you have the correct schematics and wiring diagrams.

 

[fabrozor]

@Roadking01 :
I put my hands on the pipes near the cylinders. And i hear the sound that only one cylinder has explosions inside it. Later i hear the rythm of the explosions in the both cylinders, and then the heat of the rear cylinder start to grow.

@Hoople :
I read your last message and i read you anderstood there was no blue spark.
I fear i did not explain very well.
So i'd like to explain again this spark part.
1) At the begining, i did not use the stroboscopic lamp. I only unscrewed the sparkplug and put it in contact with the cylinder to see if there was a blue spark. But i'm really not sure i did it well because i could'nt see blue spark for few seconds and when i moved the spark against the cylinder to make a good contact, spark became to appear. So, i'm not sure if there was no spark due to an electrical problem or if it was my fault for not establishing the contact well enough between spark and cylinder.
2) So i used a stroboscopic lamp.
With this tool, the sparkplug remains screwed in its place and i only plug the stroboscopic clamp onto the sparkplug wire. The clamp detect electricity in the wire and allow the lamp to light on, each time a signal is detected in the wire.
Then i started the bike and i immediatly got light from the stroboscopic lamp.
So i conclude if the lamp detects an electric signal in the wire, then there is probably a blue spark appearing in the cylinder. So, the first time (1) when i had unscrewed the sparkplug i propably did not made contact well enough.

But if you want i can make the test (1) again (unscrew the sparkplug) and more carefully make contact between sparkplug and cylinder to be sure if a blue spark is produced.
Otherwise, i can just remain with the conclusion that : "if the stroboscopic lamp lights, then that shall mean that a blue spark is produced".

 

[Hoople]

If you feel the spark is in fact jumping the gap like it should and you swapped injectors, then it does not leave you a lot of choices.

As long as you do Not have a piggy back fueler in the picture (and you should NOT at this point), I would say the rear cylinder is getting fuel. Your getting spark and you have changed the plugs.
You swapped injectors and the rear cylinder is still miss-firing on start up.

The Compression of your engine should have been taken a long time ago. Your at the point where you must obtain the tools to move forward if you want to fix this problem yourself.
It is beginning to sound like weak compression "build up" due to some mechanical problem.
I myself usually take testing to an extreme in order to come up will conclusive evidence when making or performing a repair. I always try to cross check my readings to each other. Since you only have a Very short time when the problem happens (5-10 seconds), those few seconds are VERY valuable.
I would have a compression tester in EACH cylinder at the same time just to see the COMPARISON of front to rear compression during those 10 seconds. Yes, I would need two testers but the knowledge I gain far outweighs the cost for me. I have purchased very expensive tools only to be used once or twice just because I wanted to gain the knowledge...

BTW... a blue spark (entry point #46) is not really what you want to see. Blue is better than no spark at all but there is more energy in an Orange spark than Blue. The more available spark energy you produce, the more "left over" spark energy you will have. That left over energy is used up in the form of spark duration. The Longer the spark remains across the gap, the more it's appearance will be Orange. As the spark goes from blue to Orange, it's appearance will also get much thicker and fatter. Blue sparks are generally very thin in appearance. If you see an Orange spark,,, "you are there".

 

[fabrozor]

Very interresting information this orange spark thing.

I used the word "blue spark" but that was a way for me to be anderstood.
In fact i did not check the true color of the spark.
I will try to get the tools to controle the compressions in each cylinder.

 

[fabrozor]

In the stored codes, i have a P0108 code.
It doesn't remains activ, it's only stored in the history log.

Today i bought a compression gauge to test cylinder compression, but there is no right size adapter for our sparkplug diameter. I have to make one with an old spark plug and find someone to solder that.

On french forum, i told you thought about lifter weakness, they think about a weak coil.

Here are the news...

 

[Hoople]

In the stored codes, i have a P0108 code.
It doesn't remains activ, it's only stored in the history log.

At entry points #15 , #35 and #41 I asked if there were ANY stored error codes in the ECM. Now at entry point #45 you tell me you have a stored P0108 MAP code.

I tried to help you I really did but we are going in circles. I am sure the others will get you going.

 

[Jack Klarich]

In the stored codes, i have a P0108 code.
It doesn't remains activ, it's only stored in the history log.

Today i bought a compression gauge to test cylinder compression, but there is no right size adapter for our sparkplug diameter. I have to make one with an old spark plug and find someone to solder that.

On french forum, i told you thought about lifter weakness, they think about a weak coil.

Here are the news...

Bad lifters and weak out put from the coils could pose a problem. The coils can be checked with an ohm meter if you have a manual or know the values

 

[fabrozor]

Hi again guys,

I just come back from my garage. I did several things but i did not start the bike because it's 22:20 and i'm tired, i'll start it tomorrow.

- I tested the coil with an Ohm-meter and here is the result :


- I switched the spark wires/cable. (remember i already switched the injectors).
- I put new spark-plugs again.
- I removed the intake manifold and changed the both intake manifold Seals (between intake manifold and head).