Xb9r has fuel, spark, crank no start

[MR149818]

First post here. Hey everyone I bought a 2003 xb9r this spring. Bike sat 2 years. The guy I bought it from jump started with old battery, gas etc and it ran but not well.. so I bought the bike and Did some basic maintenance (new battery, plugs, oil change and muffler) Bike cranks over good, headlight on, needles sweep and no cel lights on the dash. With muffler off and a couple reps of cranking about 10 seconds I smell gas and have a few drops come out the exhaust. I pulled off the plug wires from the plugs and put a new plug in each one outside the bike and both are sparking. It's a weaker campfire orange spark IMO but still a spark. I don't understand why it won't start now. Ground? Weak Coil? Any ideas Appreciated

 

[Barrett]

Sir: Possibilities are:
Fouled spark plugs---you've eliminated that
Simultaneous failure of both spark plug wires---highly unlikely
Failed CPS---your symptoms indicate unlikely
Failed ECM---likely
Failed Coil---likely
Failed ECM ground circuitry---likely

Do you have a simple test light and multi-meter with OHM testing capability? If so, report back and will give you simple steps to test Coil....ground....CPS....ECM

 

[MR149818]

Barrett,
Yes I have a fluke meter. That's kind of what I was thinking next was coil due to weak looking spark but not sure. So what's the next step?

 

[Barrett]

Troubleshoot as follows which will confirm coil...ECM...CPS condition. The Service manual electrical section shows simple single-fire coil condition test via OHM meter so no sense walking you thru that. That test will reveal coil condition via OHMS testing.

DO THIS WITH SIMPLE 12V TEST LIGHT:

Remove airbox cover...airbox lid...airbox baseplate to reveal coil pack and wiring harness that plugs into coil

Unplug the 3 wire electrical harness from it.

Attach the alligator clip of your test light to the negative terminal on your battery. Now touch test light probe to the positive terminal of the battery and make sure your test light activates.

Turn the key and kill switch to ON and do NOT attempt to start.

With wiring harness unplugged from coil...probe the gray wire terminal of the harness and test light should turn on.

Remove alligator clip from negative battery terminal and attach it to positive batt terminal. Now touch test light probe to negative batt terminal and make sure light activates.

Now while probing the Y/G wire of the harness, crank the engine as if to start it. While cranking, you should see your test light pulse (it will flash to the rhythm of the crank turning)

Repeat the step above for the BL/R wire on the harness end and you should also have the same pulse.

This confirms ECM....CPS....start relay...wiring harness....all doing their job.

If so, you likely identified a failing coil.

 

[Outlaw]

Nice simple step by step. John you are a patient man and a mentor .

 

[MR149818]

Well I've got some updates. Went through the above mentioned steps, coil seems to be working good. Tested between coil terminal a and ecm 10-7 and terminal c and ecm 10-6. I followed the crank no start steps in the manual again and actually found my accessory fuse holder to have an open on the back side if you moved it just right. Repaired and followed the new flow chart in the manual which took me through a few other sensors checking for resistance and/or continuity. Sidestand switch was showing 3.2 ohms. I know the book wants 1 ohm or less so I temporarily bypassed it by jumping the connector.. Where I stopped last night was the cam sensor. Correct me if I'm wrong but I believe it was terminal c on connector 14 (cam sensor) that went to the ecm (don't remember which pin) and should have 1 ohm or less resistance. Well I had OL on all 3 terminals a b and c to the ecm. So the book had left me at a roadblock saying replace ecm. I can look after work for the exact ecm pin number tonight if that helps, I just can't remember it off the top of my head. Now on a side note, I'd hope the book is wrong and maybe it's the wiring between cam sensor and ecm, but I won't know until tonight. Had to call It quits at that point yesterday.

 

[Barrett]

Nice simple step by step. John you are a patient man and a mentor .

Hi Josh and thanks much for the very kind words.

Sir: Revert back to your post used to initiate this thread. Then consider what you've tested as per my instructions above.
IF the "test-light" procedure I outlined for you is correctly pulsing the light....then the CPS is doing its job....AND...the ECM is seeing necessary signal from CPS and delivering necessary signal to the coil. I can't make it simpler than that. If the spark at the plugs is extremely weak, then all indicators are a failing coil. You are observing what you described as a visually weak spark at each plug when testing. This is at atmosphere. Under compression, that spark most likely is extinguished.
The only other procedure check I can think of at this point, is to remove the front belt pulley cover....access the 3 wire CPS-to-main wiring harness plug...separate same...check for corrosion and any sketchy wires feeding same...clean and lube...and reattach. It's the only harness plug in that bundle behind the cover that has one end disappearing into the actual cam cover.