Odd fire V-twin only starting up on Cyl No1

[Norzilla]

Hi

I have my 60 deg V-twin Aprilia firing up on only the no. 1 cylinder...... there is spark on no.2 but it won't fire/ignite the fuel mix,so timing must be out.

As the motor is sealled it has no way of using a timing light to check the timing of the no.2 cylinder spark, can anyone help with ideas on how to solve my timing problem?

Data re hardware.

1) 36-2 wheel
2) Cam trigger occurs during the missing teeth on the crank trig
3) tach tooth is tooth 31 of the 34 real teeth and occurs 5 deg BTDC so using delay tooth = 30 , crank rotates anti clockwise.
4) as it is an odd fire motor with 60 deg V, the no 2 should fire 300 deg after cyl 1, so i am using Offest advance = -295 deg ( ie the +5 deg BTDC + the 295 ATDC = the 300 deg to the Cyl 2 TDC
5) skip teeth = 36 ( don't really understand why, but reading instructions 36 teeth/ 1 tach event per crank rev )

What am i doing wrong here?????

thanks

John

[grippo]

You want to use delay teeth = 1 and trigger advance offset (in regular ignition options menu) = -10 deg (atdc). This takes care of cyl 1. The 2nd cyl would, on an even fire engine, fire 360 deg after cyl 1, so this one has 60 deg more advance that has to be added to the spark advance table. So you set the 2nd output advance offset to +60 deg (in the advanced ign option menu).

You set skip teeth (the amount between cylinder firings on an even fire engine) to 36 because you want to fire each cylinder every 720 deg and you have 2 cylinders in sequential mode, so a cylinder will spark every 360 deg (on an even fire engine, but since you have odd-fire you will add an extra 60 deg advance to the second cyl).

[Norzilla]

Thanks for this response.

I have now tried the setting of +60 deg adv offset ( although its seems to contradict all the text in the manual ) and it works on cylinder 2. I am still pretty confused on the cyl 1 related settings ie delay tooth =1 and adv offset = -10 deg as no. 1 cyl was firing with the setting of delay teeth = 30 and adv offset = +5 deg. Is there any advantage to the alternative setting?

Now i have both cylinders firing but as soon at it fires it dies, maybe 10 cycles only then rpm goes to Zero. Another things is that as soon as i touch the throttle it dies.

I do not have any Idle control connected at this point , so have manually adjusted the idle screw for the time being.

what areas should i now look at to achieve an idle?

Thanks
John

[24c]

Now i have both cylinders firing but as soon at it fires it dies, maybe 10 cycles only then rpm goes to Zero. Another things is that as soon as i touch the throttle it dies

When this happened to me, and it was interference/noise in the system, that caused me to lose sync. Sorry I can't help any more, as haven't got any further on the bike yet. If you start a datalog, and post it, the guys will be able to help you more.

PS As you first need to achieve a stable idle, before doing anything else, you might find it beneficial to put a flat spark table map. The spec says your engine is set a "5 deg BTDC upon starting", I would think 10 degrees at idle would be enough in your case, so I'd make sure the whole map was at 10 degrees from sub idle to max revs, and for all MAP values. Then any variations in these wouldn't affect your advance, plus you could "calibrate/time" your engine.

[Norzilla]

Thanks i will try that tomorrow, sounds like a good suggestion re the spark map, as it romoves one of the variable.

I will also psot a couple of datalogs

Cheers and will keep updating on progress.

[Norzilla]

Further Updates:

The motor is now running all be it not well ( YET)

Based off Grippo's advice i set the following:

1) Delay tooth =1
2) Offset adv = -65 deg
3) Leaving Odd fire timing adv at 60 deg as before

The result was the engine would not fire...... however what was evident from the following datalog of cranking was the cranking RPM signal was picked up almost instantly and was more consistant than the setting that WILL run the engine.

Datalog 031009 013.msl

Datalog of cranking at with delay tooth 1 setting

(24.74 KiB) Downloaded 58 times

Taimoshan 031009 001 delay tooth1 .msq

msq file of deley tooth = 1 setting to match the datalog 031009 013

(25.03 KiB) Downloaded 57 times

Attached below is the msq ( see next posting as can only add 3 files) and datalog of the delay tooth =30 setting which allows the engine to run at idle but dies when RPM signal is lost, then the next cranking events after signal dropout will not recongnise the RPM signal until the system is powered down then up again.

Datalog 031009 005.msl

datalog for delay tooth = 30 setting , showing crank to run and die then no RPM on next cranking

(278.96 KiB) Downloaded 56 times

The other things i have tested:

1) I have also tested delay tooth = 31 and adv offset = -5 deg , ie the tooth on the other side of TDC and that works just as same ( maybe a little better than tooth 30, maybe not so many RPM dropouts.)

2) I have also tried delay tooth = 1 with offset = 295 deg but same result at with offset = -65 deg , engine won't fire.

It appears that the missing teeth are positioned on the wrong side of TDC to make the formulas in the code work, maybe someone can explain what is happening????

ALSO final issue that might be linked is that the motor will not rev past 2500 RPM as the RPM is lost, the tach count resets and the Trigger counts up +1 +2 +3 + 4 etc then unless the throttle is shut the engine will die completely.

Does anyone know what the cause of the trigger count up is ? I understand that trigger counting down is missing teeth added back into the tach count, so logically the other is extra teeth that are "seen" but not really there so removed from the tcah count????

I have tried an inline variable resistor on the VR Signal wire and this helped the RPM dropout issue but as the motor has only poor maps i can not rev much past 3500 without lots of leanout. The resistance level at which an improvement was shown was about 3k Ohms.

I think there might be an advantage to the delay tooth = 1 setting, if i can get it to run the motor , as i appears to be a faster and stronger crank to RPM signal setting and may overcome the tach resets / wont rev past 2500 issue.

Does anyone have any ideas?

[24c]

If you are getting Tach resets, you might have noise on your crank & cam sensors. I had all sorts of problems and eventually I was able to cure mine by using Zener diodes to isolate the common sensor ground that share the same pin on the MicroSquirt, but I don't know if it would work for you.

PS Just looked at your datalog, I can't see the same "noise" faults & Tach resets I had, so ignore above. Your cranking rpm is set at 500 not the usual 350, is there a reason why it needs to be higher
Does the bike idle OK or is 2000+ rpm the idle speed ?

PPS If the delay tooth=1 works better for cranking detection, why not switch the sparks to the other cylinder, and time that one up with the req'd offset etc.

[Norzilla]

If you are getting Tach resets, you might have noise on your crank & cam sensors. I had all sorts of problems and eventually I was able to cure mine by using Zener diodes to isolate the common sensor ground that share the same pin on the MicroSquirt, but I don't know if it would work for you.

PS Just looked at your datalog, I can't see the same "noise" faults & Tach resets I had, so ignore above. Your cranking rpm is set at 500 not the usual 350, is there a reason why it needs to be higher
Does the bike idle OK or is 2000+ rpm the idle speed ?

PPS If the delay tooth=1 works better for cranking detection, why not switch the sparks to the other cylinder, and time that one up with the req'd offset etc.

The cranking RPM is 500 because on a good battery it cranks at about 430-450 RPM.

The bike idles fine at about 1300 RPM ... pretty smooth but it loses tach sync and the engine dies after a while, then the motor cranks but won't start until it is powered down and the re-powered.

Re the delay tooth = 1 issues, i tried swapping the spark plugs and retiming the the system, but maybe i get the figs wrong, infact i tried a few different setting config be still now joy..... I am a bit lost unless someone can look at the timing and tell me what setting to try?



In addition with the delay tooth = 30 config the odd fire timing adv is set to 60 deg as TDC #2 is 300 deg after TDC #1 or 60 deg advanced on tach 1

[Norzilla]

As promised, here is the MSQ for the delay tooth = 30 setting that will run the engine.

[OB6D]

Thanks i will try that tomorrow, sounds like a good suggestion re the spark map, as it romoves one of the variable.

I will also psot a couple of datalogs

Cheers and will keep updating on progress.

Under ignition options you can set the timing to be fixed, you don't have to change the whole table.