RE: HELP Coil has juice, but no spark

["Michael S. Sweigart" <msweigart@domain.elided>]

Chris,

Thanks for the input. I checked rotor, cap, and the wire going into the
distributor. I cleaned the terminals on the plug going into distributor
as well. All seemed good. I also pulled the white plastic cover from
under the rotor and looked around and saw nothing suspicious like broken
wires, melted plastic, etc.

I do not have a dwell meter but have used one in the past- I may be able
to get my hands on one this weekend. 

I did the following to test the coil for badness by using an electrical
light tester (not sure the proper name for it but it is a metal spear
with a lightbulb attached on one end and a long wire with alligator clip
on the other)- you know the type- put one end on a ground and the other
end on a hot wire and if you have a good connection then the lightbulb
goes off:

So this is what I did to troublshoot:
1) Attached wire (via alligator clip) to a known ground 
2) Connected the other end of this electrical continuity tester gadget
to the positive terminal of the coil.
Results: with key off the lightbulb was not on, with key on the
lightbulb was bright
2a) shouted "whoo-hoo, we have juice going to the coil"

3) So then I put the tester into the coil connector (where the coil wire
enters)
4) Turned key on, no lightbulb lit up   - cranked engine, no lightbulb
still
4a) cursed "shazbot, the coil is shot"

5) Bought a new coil for $16, installed
6) Tested again, still same results as previous
6a) scratched head, looking for clues 

Also cleaned the ignitor (ignition module) connections with sandpaper
but still no difference. 

Will one of these lightbulb-type testers actually light up on a properly
running engine if you were to plunge it into the coil wire area? I would
think so since the amount of spark coming out of it is pretty strong. So
I am guessing that whatever controls the release of spark from the coil
is broken. Either the ignitor, or perhaps something previous to the
ignitor like the lead from distributor. So if nothing is telling the
coil to release spark, then no spark.

How much does this ignitor typically cost? Any ideas?

Michael S. Sweigart
PureDealer, Inc., President
http://www.puredealer.com
Direct Phone: 609-977-5050
Fax: (253) 323-6230
 


-----Original Message-----
From: owner-alfa@domain.elided [mailto:owner-alfa@domain.elided] On Behalf Of
christian147@domain.elided
Sent: Wednesday, February 06, 2002 9:30 PM
To: alfa@domain.elided
Subject: Re:HELP Coil has juice, but no spark


Lets go for the short story on the coil.  You should see battery voltage
on the + terminal of the coil at all times (with the key on).  The
silver box switches the ground on and off.  The spark happens when the
ground is switched off.  Easiest way to see the switching is with a
dwell meter or a duty cycle meter.  Dwell meters were cheep but are
getting hard to find.  duty cycle meters can be found on some of the
whizz bang digital multi meters in the $100 range.  With dwell meter set
to 4 cylinder, look for at least 5 degrees while cranking.  Duty cycle
would be 5-10% cranking.  If you have that and no spark, bad coil.  if
you don't have that then that silver box (called an ignitor) isn't
switching.  Ignitors do go bad , but not often.  Look at the wire that
plugs into the side of the distributor.  Is it tight? Take the cap and
rotor off the distributor, then remove the dust shield and look at the
wires coming from that connector to the sensor.  Do they still have
insulation on
them?  are they broken?   Unplug the ignitor and test for continuity to
ground from the distributor plug(if  2 wires no continuity to ground, if
3 wires, continuity on only ).  Check for continuity to ground of the
distributor sensor(should not be continuity to ground, sensor resistance
I would guess from 400 to 3000 ohms, I haven't had my hands on one for a
long time).  If all that looks good then its ignitor time.

Chris Hall  

--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided

--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided