S2 Crank but no start. Low d09

[jomor147]

Disappointment..

 

[Gary in NJ]

That’s a very inconsistent spark.

 

[Motogiro]

Disappointment..

Throw your scope on the negative side of the primary of the coil supplying that spark.

 

[jomor147]

I will do that. I will also check voltage drop between battery + and coil positive supply.

New spark plugs and eBay coils are on their way too.

Voltage drop between battery- and chassis is 0.014V so the main ground seems ok. Even though I have improved the ecu ground (voltage drop from 0.25v went to 0.07v with extra wiring) I would like to check all other grounding points, but I can't locate any. The only one i have found is behind the instruments cluster (S2 half fairing version). There are two grounding "spiders" near the ecu which I have cleaned but I was not able to locate and follow the wire that actually goes to chassis. Any other known grounding points?

 

[jomor147]

I fitted a new battery.
Voltage drop between battery positive and coil positive is 1V. It should be lower IMHO. I also replaced the spark plugs which I gapped at 0.6mm - 0.65mm. I also installed a set of used coils I ve got from ebay. I cleaned the caps interiors and made sure I have connectivity as shown here

The bike started instantly but I am getting misfires on cylinder 4. Same cylinder I was seeing intermittent sparks with the spark tester.
Cylinders 1,2,3 have approximately the same temperature while cylinder 4 is about 90°C cooler. What does this tell us
1) bad command from ecu? ( should #1 have the same issue?)
2) bad HT lead ?
3) bad connection between HT lead on the cap or cap - spark plug? Ceramic resistor is in spec.
4) bad coil ?

 

[jomor147]

I rechecked spark plug is torqued tight and replaced the cap with one of my old coils. Same result.

 

[Motogiro]

Number 1 and 4 cylinders should have the same spark so I doubt it's an ECU control issue. Sounds like a big gap between the coil HT wire to number 4.
Maybe bypass the ceramic resistor for a test.
If it's possible to swap the 1 and 4 HT wires for a test.

 

[jomor147]

Number 1 and 4 cylinders should have the same spark so I doubt it's an ECU control issue. Sounds like a big gap between the coil HT wire to number 4.
Maybe bypass the ceramic resistor for a test.
If it's possible to swap the 1 and 4 HT wires for a test.

All caps were dismantled, cleaned and tested for continuity before fitting. Back screw, spring, resistor = exactly the resistor value, end brass terminal and spark plug contact = 0 ohms. Caps are ok, firmly screwed at the ht lead of which the inner strands were exposed, straightened and cleaned before screwing the cap. My car mechanic suggested to swap injector 4 with 3 for example to see if the cold cylinder moves. What i haven't be able to inspect is the ht lead connection to the coil side. I chickened out removing the holding clip.
I can always put back the old 1-4 coil to check the temperatures, I should have tested this before, but i haven't. I still have much to learn.

 

[Motogiro]

Switching Injectors sounds logical except I thought you were experiencing a spark issue at #4 but not #1

 

[jomor147]

All the spark tests i did in the past while the engine was refusing to start were on #4 due to accessibility ease. So i can't be sure if I had missing spark on other cylinders too.

 

[jomor147]

Today i tried to track down the 1V drop from B+ to coil positive.
I have 0.4V drop from B+ to red/white on the cutoff relay (0.25v of which is due to ignition key switch). Another 0.35 from red/white to red/black (kill switch). The rest is fuse contacts, cable loss, plugs. I tried to clean the kill switch. On the street. Late afternoon. Got dark before realising it. Daaang... ball and spring flew away. Could not see my nose. Found them and put everything together... went to hell and returned.

 

[jomor147]

For 10 days after replacing the battery and the ignition coils the bike was starting just fine. Until yesterday, where the problem happened again. I visited a new mechanic, gave hime the whole story, showed him some videos and his opinion is that i have to check the starter motor. He asked if i have ever replaced it or repair it (never replaced, brushes replaced a year before this issue appeared) and seemed weird to him that i have 98.000km with the same starter, since the only frequent failures the fz6 that he has faced were the magneto and the starter motor. He also noticed that in cases the engine started there still was a delay of about 1", it should be quicker. He is not fond of aftermarket brushes, has seen cases of creating bad connection or nearly shorting (thus creating the voltage collapsing making it seen like a mechanical lock that i am facing every once in a while). Regarding the missing sparks he said that if due to bad brushes if the motor spins with less rpm (not noticable by ear) the cps signal will be weaker (perhaps any residues or debri on the sensor makes things a little worse). On the other hand i am seeing a clear signal on the scope. He suggested a push start next time to verify the theory, which was also mentioned in this thread also.

 

[jomor147]

Question, am I allowed to crank while being in d09 mode ?

 

[Gary in NJ]

Obviously yes. Without cranking the the ECU can not receive signals from the various sensors that determine codes. If it were distructive to crank the engine, there would be a lock-out from the ECU.

 

[jomor147]

ah, silly me, never tried it. The mechanic suspects the starter motor sometimes draws more current than it should for a moment, resetting the ecu or weakening the voltage at the coil's primary winding, thus the missing sparks. AI says that bad quality motor brushes or other internal malfunction could feed back to the ecu strong intefering noise, making the ecu dificult to read clearly the cps or other sensors, which is just a theory, but.. The fact that the issue seems to be more rare after replacing the battery gets me back to eliminating the voltage drops i started the troubleshooting with, before investigating the starter motor itself. Where the heck does the battery grounding cable connect to the chassis...

 

[jomor147]

Tried cranking at d09. It did not start, I suppose it should not, correct?

Battery voltage at 11.5V
d09 at 10.8V
Battery- to chassis 0.2V

Forgot to measure δV between B+ and coil +
I should also measure current draw just for curiosity.

 

[Rob3rto]

Tried cranking at d09. It did not start, I suppose it should not, correct?

Battery voltage at 11.5V
d09 at 10.8V
Battery- to chassis 0.2V

Forgot to measure δV between B+ and coil +
I should also measure current draw just for curiosity.

When you have 11.5 V at the battery, what voltage do you measure at the ECU input, between the red wire and the black wire? There are two black wires. Do you get the same voltage as at the battery, or is the voltage lower at the ECU?

 

[jomor147]

This was supposed to be my next step, measure directly on the ecu.

I have drops at the ecu voltage (i mean the red/white and black). I do not consider the d09 (red/blue) as ecu power supply since its switchable, so i suppose the ecu healthy operation depends on the red/white and the grounds.

I have 0.26V drop at red/white (was 0.4V and reduced it after i bridged the red wire from the starter relay to the regulator's + input ( the regulator's factory shocket was available, i ve fitted a SH847 regulator with its own wiring). I also have a 0.07V drop between ecu black (one of them) and the chassis (was 0.24V and reduced by bridging the factory regulator's negative to chassis. It seems that i had a grounding issue before this mod. I should measure directly the voltage though, these calculations are making it more complex at the end.

 

[Gary in NJ]

Try cranking with a boost pack. 11.5vdc static is not enough battery to start the engine due to ECU dropout.