Primary and secondary coil test readings

1993 FORD ESCORT
79,084 MILES • 1.9L • 4 CYL • 2WD • AUTOMATIC
Avatar
MS THUMPER
  • MEMBER
  • 19 POSTS
I am trying to test the primary and secondary coils. I do not have factory specs on what the coil readings should be. Can you offer some help with that? And the correct procedure for testing them?
Nov 2, 2017 at 7:54 AM
Advertisement
Avatar
PATENTED_REPAIR_PRO
  • CERTIFIED EXPERT
  • 1,853 POSTS
Here is that procedure:
1.Turn the ignition key "off".
2.Unplug the coil pack from the vehicle harness connector.
3.With the EDIS diagnostic cable negative battery lead connected, disengage the positive lead.
4.Measure the resistance between terminals VBAT + and C1 with a digital volt Ohmmeter (DVOM) set on the two kilohms scale. Refer to the accompanying illustration.
5.If the reading is not greater than 0.4 ohms, replace the coil.
6.Measure the resistance between terminals VBAT + and C2 with a DVOM set on the two kilohms scale. Refer to the accompanying illustration.
7.If the reading is not greater than 0.4 ohms, replace the coil.

Figure 2: Measure the resistance between the EDIS coil pack terminals VBAT + and C1 with a DVOM set on the two kilohms scale.

Nov 2, 2017 at 8:33 AM
Avatar
PATENTED_REPAIR_PRO
  • CERTIFIED EXPERT
  • 1,853 POSTS
Fig. 1: Probe the terminals of the coil pack with a DVOM to check resistance.
Nov 2, 2017 at 8:34 AM
Advertisement
Avatar
PATENTED_REPAIR_PRO
  • CERTIFIED EXPERT
  • 1,853 POSTS
That does not look right, let me try this.
Nov 2, 2017 at 8:35 AM
Avatar
PATENTED_REPAIR_PRO
  • CERTIFIED EXPERT
  • 1,853 POSTS
or maybe this,
Nov 2, 2017 at 8:36 AM
Avatar
PATENTED_REPAIR_PRO
  • CERTIFIED EXPERT
  • 1,853 POSTS
That is better
Nov 2, 2017 at 8:36 AM
Avatar
MS THUMPER
  • MEMBER
  • 19 POSTS
Is it the same for the secondary coil as well? And would happen to know the specs for spark plug wires are?
Nov 2, 2017 at 11:22 AM
Avatar
PATENTED_REPAIR_PRO
  • CERTIFIED EXPERT
  • 1,853 POSTS
What secondary coil are you referring to?
Spark plug wires are normally like 7,000 ohms per foot.
Nov 2, 2017 at 1:12 PM
Avatar
MS THUMPER
  • MEMBER
  • 19 POSTS
The ignition system secondary coil. These car has a electronic distributor-less ignition system (EDIS), but has a distributor and spark plug wires. Can you maybe explain what exactly this means? So would that make it a waste spark or what? The little bit of service information I have been able to find is very confusing.
Nov 3, 2017 at 10:23 AM
Avatar
PATENTED_REPAIR_PRO
  • CERTIFIED EXPERT
  • 1,853 POSTS
I think you mean the secondary ignition coil circuit, not necessarily a secondary ignition coil.
The secondary circuit is the high voltage side of the coil packs where the spark plug wires hook into.
Yes this does have a waste spark, "The ignition coil fires two spark plugs simultaneously, one on the compression stroke and one on the exhaust stroke."
Nov 3, 2017 at 1:07 PM
Avatar
MS THUMPER
  • MEMBER
  • 19 POSTS
Ok, now its starting to make a little more sense. Thank you for your time. I managed to get the tests done. Thanks again.
Nov 7, 2017 at 11:35 PM
Avatar
PATENTED_REPAIR_PRO
  • CERTIFIED EXPERT
  • 1,853 POSTS
Did the coil pass? Is the engine running? Why was you wanting to test the ignition in the first place?
Nov 8, 2017 at 4:35 AM
Avatar
MS THUMPER
  • MEMBER
  • 19 POSTS
A friend's car I've been trying to help them with. Yes the coil passed. It now has a dead battery. So about it running, still waiting to see.
Nov 8, 2017 at 11:51 PM
Avatar
PATENTED_REPAIR_PRO
  • CERTIFIED EXPERT
  • 1,853 POSTS
Ok, thanks for letting me know.
Nov 9, 2017 at 4:23 AM
Avatar
MS THUMPER
  • MEMBER
  • 19 POSTS
Thank you for your help.
Nov 12, 2017 at 6:55 AM
Avatar
PATENTED_REPAIR_PRO
  • CERTIFIED EXPERT
  • 1,853 POSTS
You are welcome.
Nov 12, 2017 at 7:19 AM
Avatar
MS THUMPER
  • MEMBER
  • 19 POSTS
Do you know anything about 142f engines? single cylinder, 4-stroke engine.
Nov 15, 2017 at 12:18 AM
Avatar
PATENTED_REPAIR_PRO
  • CERTIFIED EXPERT
  • 1,853 POSTS
No, not really.
Nov 15, 2017 at 4:42 AM
Avatar
MS THUMPER
  • MEMBER
  • 19 POSTS
Ok, not a problem. Thanks again.
Nov 18, 2017 at 11:38 AM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
Do you mean the engine used for portable pumps, etc?

Those are small cc engines.
Nov 20, 2017 at 6:57 PM