Re: Monitor Automotive Spark Plug?

On May 16, 12:13 am, Clint Sharp <cl...@xxxxxxxxxxxxxxxxxxxx> wrote:
In message <b7GdnT1B_esaR5DXnZ2dnUVZ_sqdn...@xxxxxxxxxxxx>, eeboarder
<jme...@xxxxxxxxxxxxxxxxxxxx> writes>is
the signal just a simple pulse?

No. It's got several distinctly different characteristics, you can tell
an awful lot about the quality of the engine and ignition system with
the spark signal.

Hi
This used to be true when the typical coil continued to
dump energy into the spark plug, long after the flame front
left the plug.
The capacitive discharge systems most often used today
only create a short pulse that is too short to get any
useful reading on the preasure changes right after the
flame is ignited.
With the long discharge, one had a voltage signal that
was proportional to the pressure. Too fast a burn rate
would indicate a lean mixture and too slow would indicate
too rich. Jumps in preasure might indicate detination from
buildup in the cylinder. A low line could mean low compression.
But, as I said. All that information is lost in the short
pulse of todays more efficient ignition systems.
Dwight


What kind of current is there? Does the
current create the spark and then return through the same cable?

I just hooked a split core current transformer with 3000 windings
around a
spark plug cable and got nothing. I'm trying to re-create a signal
similar
to that which a timing light would use.

Then get a hold of a timing light clamp and see how it's done.

Get a hold of a clamp on EMI filter, wind ~ten turns of enamelled copper
wire around one half of the ferrite and then attach a scope to the ends
of the ECW, see what sort of signal you get out. I guarantee it's not a
'simple' pulse.



Really, I would like to just know when this engine is on and off
without
any lag. I also don't want to shutdown the engine to install it.

Tap into the crank sensor, tap into the ignition coil LT drive signal or
the injector drive (assuming it uses fuel injection).

I had success using hall effect sensors on fuel injector bodies and also
on ignition coils, extremely easy to deal with and also logic compatible
if you pick the right one although a simple comparator circuit worked
best as it was adjustable to suit.

Plenty of ways to tell if an engine is running that are simpler to
interface to and measure than a spark plug lead.



Any ideas or help would be much appreciated.

--
Clint Sharp

.

Relevant Pages

  • Re: different idle mixture with premium fuel?
    ... Some of the pinging was probably due to ... Pinging could also be caused by lean mixture or advanced spark timing. ... range of the spark plug as possible culprits. ... the ignition if the engine "pinked" on acceleration... ...
    (rec.motorcycles.tech)
  • Re: Lawn mower repair question.
    ... If you pull off the spark plug wire, and hold it near the engine (mayb ... Remove the spark plug, ...
    (alt.home.repair)
  • Re: Saturn SL2 engine dies shortly after startup.
    ... > get spark while someone else turns the key. ... ignition system is weak. ... You use this tester with a short piece of rubber hose. ... over the tip of a spark plug. ...
    (rec.autos.makers.saturn)
  • Re: 95 Golf 2.0 hot starting/running problems
    ... spark plug cables by spraying them with water. ... I am thinking a weak spark. ... predictable WRT temperature and warm engine... ... the fuel pump or the fuel filter (since neither one should really ...
    (rec.autos.makers.vw.watercooled)
  • Re: Diagnose engine misfire problem
    ... if you used bosch spark plughs get rid of them they foul out real easy ... Check engine line came on and I smelt gas. ... platinum spark plug. ... but the engine is not smooth. ...
    (rec.autos.makers.chrysler)
Loading