Ignition updates to the Unofficial FAQ

After a long passage of time and much dithering, I've finally finished two
big updates.

1) New section on igniter function
http://www.tegger.com/hondafaq/igniter-operation/howworks.html

2) Coil failure
http://www.tegger.com/hondafaq/startproblems.html#badcoil

Any critical advice is welcome. I'm not an electronics engineer, so there
are surely mistakes somewhere.

 

Good job, John. Thanks!

 

Good job, John. Thanks!

 

Thanks.

Thanks are also owed to all those (including you) who helped by supplying
much valuable information.

 

Thanks.

Thanks are also owed to all those (including you) who helped by supplying
much valuable information.

 

Tegger,
Thanks again for your help. I just wanted to let you know that I received
a letter from Honda and the title of the recall notice was:
Ignition key is removable with the shift lever out of Park

I took my Honda to the local Honda dealership and they installed the
following as per the service report:
1 06351-S84-000 KIT, LEVER (A)

I don't know whether the first number 1 is part of the part number or
means that only one kit was installed. I hope this helps. I have not yet
had a chance to revisit your web site.

 

Tegger,
Thanks again for your help. I just wanted to let you know that I received
a letter from Honda and the title of the recall notice was:
Ignition key is removable with the shift lever out of Park

I took my Honda to the local Honda dealership and they installed the
following as per the service report:
1 06351-S84-000 KIT, LEVER (A)

I don't know whether the first number 1 is part of the part number or
means that only one kit was installed. I hope this helps. I have not yet
had a chance to revisit your web site.

 

A little adjustment to the graphics:

The darlington pair is the switch. Pin 3 would be the pulses from the
ECU or magnetic pickup. The tach connects either to the primary winding
(which makes radio interference) or to whatever drives the transistors.

And yes, the ignitor gets flyback voltage too. Some electronic ignition
systems still need the condenser because the flyback voltage on the
primary side otherwise rises extremely rapidly. It can rise faster than
some high voltage transistors can turn off and it can even rise before
the spark plug discharges the energy.

 

A little adjustment to the graphics:

The darlington pair is the switch. Pin 3 would be the pulses from the
ECU or magnetic pickup. The tach connects either to the primary winding
(which makes radio interference) or to whatever drives the transistors.

And yes, the ignitor gets flyback voltage too. Some electronic ignition
systems still need the condenser because the flyback voltage on the
primary side otherwise rises extremely rapidly. It can rise faster than
some high voltage transistors can turn off and it can even rise before
the spark plug discharges the energy.

 

interesting. i had 2 igniters fail inside a year on my 89 civic &
subsequently discovered that the condenser had failed. presumably,
excess flyback was responsible. but, my 91 crx has no condenser at all,
from factory. what's up with that? works fine, no r.f problems. both
have the same igniter. any thoughts?

 

interesting. i had 2 igniters fail inside a year on my 89 civic &
subsequently discovered that the condenser had failed. presumably,
excess flyback was responsible. but, my 91 crx has no condenser at all,
from factory. what's up with that? works fine, no r.f problems. both
have the same igniter. any thoughts?

 

The coil might have an internal condenser or a small shorted winding.
An oscilloscope on the primary coil would show you what's going on.

I'm doing this from memory so the shape might be a little off:


v- Spark plug discharge

|
|
|#
|##
| |
| |
| |
--- | --------------------------
-----------

^ ^ ^ flyback
| charge
open circuit


Without a condenser, the initial spike is much higher and it rises so
steeply that it might not produce a visible trace on the oscilloscope.



|

 

The coil might have an internal condenser or a small shorted winding.
An oscilloscope on the primary coil would show you what's going on.

I'm doing this from memory so the shape might be a little off:


v- Spark plug discharge

|
|
|#
|##
| |
| |
| |
--- | --------------------------
-----------

^ ^ ^ flyback
| charge
open circuit


Without a condenser, the initial spike is much higher and it rises so
steeply that it might not produce a visible trace on the oscilloscope.



|

 

makes sense. i have an old scope so i can check between the two. thanks!

 

makes sense. i have an old scope so i can check between the two. thanks!

 

Take a look at this, from Graham W.
http://www.tegger.com/hondafaq/misc/rov-ign.jpg

So how would I show that in the graphic? If there's a cap somewhere to
blunt the flyback, I'd like to have that shown.

 

Take a look at this, from Graham W.
http://www.tegger.com/hondafaq/misc/rov-ign.jpg

So how would I show that in the graphic? If there's a cap somewhere to
blunt the flyback, I'd like to have that shown.

 

There's a lot more in the Ignition Control Module than a darlington
pair. As I see it:

1: Tach output
2: Coil output
3: +12V
4: TDC pickup
Case: GND

The TDC sensor produces a curved waveform. Integrating the form
(high-pass) can produce the advanced timing needed for dwell.

Maybe Jim Beam can take a photo of his o-scope. My new Honda has a coil
on top of each spark plug so I'm not sure I can tap into the primary
coil. I have a circuit that drives coils but it's not quite the same as
a car ignition. Want a picture of that trace?

 

There's a lot more in the Ignition Control Module than a darlington
pair. As I see it:

1: Tach output
2: Coil output
3: +12V
4: TDC pickup
Case: GND

The TDC sensor produces a curved waveform. Integrating the form
(high-pass) can produce the advanced timing needed for dwell.

Maybe Jim Beam can take a photo of his o-scope. My new Honda has a coil
on top of each spark plug so I'm not sure I can tap into the primary
coil. I have a circuit that drives coils but it's not quite the same as
a car ignition. Want a picture of that trace?

 

i too was under the impression that the igniter handled dwell because i
know that happens with some other ignitions, but it seems that with the
honda, all that's taken care of by the ecu. #4 is the for the ecu's
output signal. the igniter just switches as soon as it gets signal.

but that said, i do have the gear to test that properly this time... i
have a spare working igniter - i'll do some more homework.