ignition condenser [= radio noise capacitor] - revisited

> wrote
> jim beam wrote:
> > so, if i understand correctly, a condenser in good working order will
> > promote a strong healthy spark - which corresponds with good engine
> > performance. now all we need to do is figure out how an igniter with a
> > built-in condenser works well with an external condenser, works well
> > with no condenser, but doesn't work as well with an aged condenser.
terry?
> >
> ++++++++++++++++++++++++
> I did some simple test Sunday afternoon.
> I got my scope back and nmade several "Speed" runs.
> Run#1 stock
> Run#2 capacitor disconnected
>
> With the cap out of circuit I noticed some "flutter" in the
> ignition drive from the ECU. I used a 100Meg to sneak a look
> at teh HV out and it too had the flutter. The primary FI had
> over a 10% reduction in n width. And accleration was sluggish.
> I expected to experience back fires but other then a very
> slight "stumble" no gross effects.
>
> It did wipe out my radio reception, both AM and FM. And The Kenwwod
> had ignition pulses while playing MP3s from a Rio self powered MP3
> player.
>
> When we got back home I pulled the floor cover from the ECU and was
> able to "see" farily high amplitude ingitno spikes that are not there
> when the cap is in place.
>
>
> With effects like this I expected to see some effect on the dwell
> time at hihger RPM , but noe was observed.
>
> So the capacitor is important, and should be checked for capacitance,
> and ESR. I wish I had a bad one, but all the ones I have checked within
> ~10%. A none issue for non tunned circuit cpacitors.
>
> As I expected adding more capacitance, IE paralleling several caps,
> made no difference.

Really interesting read.

wrote:
> jim beam wrote:
>
>>so, if i understand correctly, a condenser in good working order will
>>promote a strong healthy spark - which corresponds with good engine
>>performance. now all we need to do is figure out how an igniter with a
>>built-in condenser works well with an external condenser, works well
>>with no condenser, but doesn't work as well with an aged condenser. terry?
>>
>
> ++++++++++++++++++++++++
> I did some simple test Sunday afternoon.
> I got my scope back and nmade several "Speed" runs.
> Run#1 stock
> Run#2 capacitor disconnected
>
> With the cap out of circuit I noticed some "flutter" in the
> ignition drive from the ECU. I used a 100Meg to sneak a look
> at teh HV out and it too had the flutter. The primary FI had
> over a 10% reduction in n width. And accleration was sluggish.
> I expected to experience back fires but other then a very
> slight "stumble" no gross effects.
>
> It did wipe out my radio reception, both AM and FM. And The Kenwwod
> had ignition pulses while playing MP3s from a Rio self powered MP3
> player.
>
> When we got back home I pulled the floor cover from the ECU and was
> able to "see" farily high amplitude ingitno spikes that are not there
> when the cap is in place.
>
>
> With effects like this I expected to see some effect on the dwell
> time at hihger RPM , but noe was observed.
>
> So the capacitor is important, and should be checked for capacitance,
> and ESR. I wish I had a bad one, but all the ones I have checked within
> ~10%. A none issue for non tunned circuit cpacitors.
>
> As I expected adding more capacitance, IE paralleling several caps,
> made no difference.
>
> Terry
>
>
>
> Terry
>
excellent! thanks.

wrote:
> jim beam wrote:
>
>>so, if i understand correctly, a condenser in good working order will
>>promote a strong healthy spark - which corresponds with good engine
>>performance. now all we need to do is figure out how an igniter with a
>>built-in condenser works well with an external condenser, works well
>>with no condenser, but doesn't work as well with an aged condenser. terry?
>>
>
> ++++++++++++++++++++++++
> I did some simple test Sunday afternoon.
> I got my scope back and nmade several "Speed" runs.
> Run#1 stock
> Run#2 capacitor disconnected
>
> With the cap out of circuit I noticed some "flutter" in the
> ignition drive from the ECU. I used a 100Meg to sneak a look
> at teh HV out and it too had the flutter.

interesting. i checked, and with the good condenser in place, and the
timing service connector shorted, timing light pulses are stready. with
the sub-spec condenser, ignition timing does indeed fluctuate a little.

> The primary FI had
> over a 10% reduction in n width. And accleration was sluggish.

very interesting.

> I expected to experience back fires but other then a very
> slight "stumble" no gross effects.

stumble i expect - similar to slightly clogged injectors in effect.

>
> It did wipe out my radio reception, both AM and FM. And The Kenwwod
> had ignition pulses while playing MP3s from a Rio self powered MP3
> player.
>
> When we got back home I pulled the floor cover from the ECU and was
> able to "see" farily high amplitude ingitno spikes that are not there
> when the cap is in place.
>
>
> With effects like this I expected to see some effect on the dwell
> time at hihger RPM , but noe was observed.
>
> So the capacitor is important, and should be checked for capacitance,
> and ESR. I wish I had a bad one, but all the ones I have checked within
> ~10%. A none issue for non tunned circuit cpacitors.

i have a capacitance function on my dvm. any convenient way i can
stress test my distributor? the old condenser reads good on the dvm but
functions bad in service.

>
> As I expected adding more capacitance, IE paralleling several caps,
> made no difference.
>
> Terry
>

thanks again for your investigation terry. that's awesome.

if you have any scope outputs, it would be great to post them and maybe
have a small reference section on tegger's web site. this is just the
kind of info i love to see and am sure it'll be helpful to many others.

jim beam wrote:
> wrote:
> > jim beam wrote:
> >
> >>so, if i understand correctly, a condenser in good working order will
> >>promote a strong healthy spark - which corresponds with good engine
> >>performance. now all we need to do is figure out how an igniter with a
> >>built-in condenser works well with an external condenser, works well
> >>with no condenser, but doesn't work as well with an aged condenser. terry?
> >>
> >
> > ++++++++++++++++++++++++
> > I did some simple test Sunday afternoon.
> > I got my scope back and nmade several "Speed" runs.
> > Run#1 stock
> > Run#2 capacitor disconnected
> >
> > With the cap out of circuit I noticed some "flutter" in the
> > ignition drive from the ECU. I used a 100Meg to sneak a look
> > at teh HV out and it too had the flutter.
>
> interesting. i checked, and with the good condenser in place, and the
> timing service connector shorted, timing light pulses are stready. with
> the sub-spec condenser, ignition timing does indeed fluctuate a little.
>
> > The primary FI had
> > over a 10% reduction in n width. And accleration was sluggish.
>
> very interesting.
>
> > I expected to experience back fires but other then a very
> > slight "stumble" no gross effects.
>
> stumble i expect - similar to slightly clogged injectors in effect.
>
> >
> > It did wipe out my radio reception, both AM and FM. And The Kenwwod
> > had ignition pulses while playing MP3s from a Rio self powered MP3
> > player.
> >
> > When we got back home I pulled the floor cover from the ECU and was
> > able to "see" farily high amplitude ingitno spikes that are not there
> > when the cap is in place.
> >
> >
> > With effects like this I expected to see some effect on the dwell
> > time at hihger RPM , but noe was observed.
> >
> > So the capacitor is important, and should be checked for capacitance,
> > and ESR. I wish I had a bad one, but all the ones I have checked within
> > ~10%. A none issue for non tunned circuit cpacitors.
>
> i have a capacitance function on my dvm. any convenient way i can
> stress test my distributor? the old condenser reads good on the dvm but
> functions bad in service.
>
> >
> > As I expected adding more capacitance, IE paralleling several caps,
> > made no difference.
> >
> > Terry
> >
>
> thanks again for your investigation terry. that's awesome.
>
> if you have any scope outputs, it would be great to post them and maybe
> have a small reference section on tegger's web site. this is just the
> kind of info i love to see and am sure it'll be helpful to many others.
+++++++++++++++++++++++++++++++++++++++++++++++++
A DVM does good, but basic, capacitance tests.
To measure ESR and DA more espensive and complex gear is needed.

As to positng pix, sadly my little scope did come with a camera adaptor
option.
I have tried to take pix with my Toshiba digital camera with very
>POOR< results.
I hope to borrow a storage scope that records traces as JPGs. If/when I
get it I will
redo the tests and send Teggar the results.

I tried some low end PC based oscilloscopes with bad results. Images
blured to
the point you couldn't tell what was what.

Terry