Two non-start events

[CROSSBOLT]

Twice recently, old reliable DT300i has NOT fired on second revolution! Both times I was out on errands so there were few options. The temporary fix was key off, key on, attempt start, quit attempt after second revolution, key off, repeat. Repeat until start successful. Took about three sequences and success. Engine performed perfectly the remainder of the day with many good starts. Eack failure was after initial start, 10 mile ride, stop engine for a few minutes then fail to start. The bike is a 2013 Downtown 300i with 11000 plus miles. Valves checked at 6000 miles, no change from 3000 miles. No blinky codes on CELP light, none stored in ECU as per Kymco analyzer tool. Gas cap has been vented. Fuel quantity one half and one third at occurrence. Battery voltage guessed nominal (not measured) by start speed sounding normal. Battery voltage key on, headlamp off (I have a switch!) 12.3 to 12.4 on TPMS sub-feature.

First suspicion was code 33, injector fault which meant relay fail which has happened once before and that is what led to finding the service manual was deficient. No code should mean pump and FI had power. So what do you all think it could be? I am looking for what YOU think the possibilities may be.

[Stig / Major Tom]

Ah --- the key on, key off, key on, start sequence reminded me of an EFI bike my son had. We replaced the battery and it started and ran fine thereafter.

Just a thought.
Stig

[CROSSBOLT]

Ah --- the key on, key off, key on, start sequence reminded me of an EFI bike my son had. We replaced the battery and it started and ran fine thereafter.

Just a thought.
Stig

Yes, that was what got me a couple of years ago and the new battery fixed me, too! So I am into the third year with the Chrome brand battery and I hate to think that is the problem! But will test to consider.
1. Volts check at battery terminal during start:
     A. Volts above 9.5 = Go to 2.
     B. Volts below 9.5 = Replace battery.
2. Volts check at start relay (heavy):
     A. Volts above 9.5 or nearly so = Go to 3.
     B. Volts below 9.5 = Redo connections and repeat 2. Replace cable if no change.
This terminates test from battery internal to where the wiring system gets its power. Anything below 9.5 will generally turn the engine over but the ECU will not spark the plug.

[monkeybongos]

Faulty left brake switch?  Have you tried starting it by holding the right brake?

[CROSSBOLT]

Brake switches are in the starter circuit: no switch continuity, no spin starter.  Besides, Stig got me to squeeze both brakes during start sequence to save the switches. Thanx anyway!

[CROSSBOLT]

Did some tests today with a digital oscilloscope to find voltages during start sequence:
The horizontal yellow line on the left shows 12.4 volts steady at self-test.
The big vertical drop goes to 5.5 volts at starter initiate and rises to two bumps at 10.6 volts while cranking.
The trace then goes to 14.2 volts after start.
The dropoff at the right is when the key is turned off. The trace stabilizes at 12.6 volts.

Since this is a #12 wire direct to the battery, the battery is off the hook for the time being. I will repeat the test right at the battery when the seat and met tub is out. Then the other tests outlined above will be conducted.

The 'scope is way faster sensing and more accurate than the digital multimeter economically available to us. But these tests can be done without the scope. Most of today was setting the scope up to answer my questions more than actually trouble shooting the starting glitch.

By the way, all the vertical spikes up and down are when the system turns stuff on and off like the O2 heater and ISC motor.

Oh, by the way, about five cold starts. Each one perfect...

[CROSSBOLT]

Set up this morning to attack this with tests. First start failed! Good! That means I may be able to find the cause!
10.6 volts at battery during cranking, 9.5 at ECU. THAT MEANS NO START!
Now if I can get the rear body off....did this on the other one....service manual is a joke...

Got the rear body off (separate post with pictures on that) and the terminal lug for the main electrical branch was corroded in the crimp. Really does not show in the picture but it was black with a hint of green! The blue is the replacement lug with silicone dielectric grease before the crimp.

[monkeybongos]

Squeezing both brakes is better than one at a time and alternating sides?

[CROSSBOLT]

Squeezing both brakes is better than one at a time and alternating sides?

Both at the same time is better as Stig pointed out last year because there is no relay for the brake light which is high current for these tiny switches.

[CROSSBOLT]

Update:
While replacing that terminal lug was an improvement for the long term, it was not the cause of no start. Neither was the battery. Did a spark test today which was good. Inspected the air filter and drained the puke tube but neither of them was the cause. The only thing left was fuel. Injector or pump. Pulled the injector with hose left connected and hit the starter. NO SPRAY! Disconnected the hose...shut it off! Shut it off! Not the pump!

Did you guess there is NO ONE within 40 miles that can test, clean or even pressure test a gas fuel injector? So this thing is plugged. How to clean? So I filled up the tube on the injector with carb cleaner, hooked up the hose and cycled it several times and blew it out! Once a fairly steady pattern emerged, hooked everything back and it started normally!

Gotta have: fuel, air, spark and spin. Miss one and no start.

[Stig / Major Tom]

Update:
While replacing that terminal lug was an improvement for the long term, it was not the cause of no start. Neither was the battery. Did a spark test today which was good. Inspected the air filter and drained the puke tube but neither of them was the cause. The only thing left was fuel. Injector or pump. Pulled the injector with hose left connected and hit the starter. NO SPRAY! Disconnected the hose...shut it off! Shut it off! Not the pump!

Did you guess there is NO ONE within 40 miles that can test, clean or even pressure test a gas fuel injector? So this thing is plugged. How to clean? So I filled up the tube on the injector with carb cleaner, hooked up the hose and cycled it several times and blew it out! Once a fairly steady pattern emerged, hooked everything back and it started normally!

Gotta have: fuel, air, spark and spin. Miss one and no start.

Good for you Karl!
Let's hope that was not a one-off good start.
Intermittent starts are a pain to track down!
Injectors are just not prone to clogging as long as the fuel filter is working - and those things do their jobs a heck of a long time, usually.....or most of the USA would be walking home.
Not using Bait-Shop gas are we? (Top Tier costs no more …. )
Stig

[CROSSBOLT]

I'm guessing it's some of that ethanol sludge from sittin' at the dealer for three years before we bought it. Only took four years to clog things up! We will know tomorrow morning!

[CROSSBOLT]

Started right up! Took one more step that can apply to any single injector for virually built-in cleaning! Take the hose off, remove injector from inlet but leave it connected to harness, clamp hose on the spray end. Then try the start sequence in short bursts. This slowly flushes the fuel path clear! Picture shows the hook up.

Second picture shows the pop-out panel that MUST be removed to get at two 10 mm hex nuts to remove the rear light assembly and the body work. There are two Phillips screws up forward at the whit/black junction. Total hardware to be removed to get the tail off:
4 Phillips
2 10 mm bolts
2 10 mm nuts
That panel previously mentioned had to be popped loose from the inside. There are 4 tabs into slots that had to be driven loose using 1/4" extentions and a small hammer! You AIN'T getting it off from outside!

[CROSSBOLT]

Update: was assigned a "honey-do" store trip today and this thing nor the first one EVER started so quickly! I swear, it rolled over once and fired right up! At home, at the gas station and the store! Usually it would consistently take two to fire!

Now that I have bragged.....