coil testing
Thread Starter
Instructor
Joined: Sep 2015
Posts: 132
Likes: 8
From: Waretown NJ
coil testing
I have been trying to check resistance on my coil. All the info I have found talks about ohm values for a coil with external resistor. Are the values the same with an internal resistor? if they are different, would someone know what ohms should be? thanks, rob
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,847
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
You didn't say what year the car was, but I ran the part number and I'll assume it's a 1974 or older car.
What problem are you having to check the new coil?
Normal resistance would be around 1.5 to 1.7 on the primary side. On the secondary side with your meter in the 20K setting you should read 11.0 or higher and anything less would be an issue.
Willcox
What problem are you having to check the new coil?
Normal resistance would be around 1.5 to 1.7 on the primary side. On the secondary side with your meter in the 20K setting you should read 11.0 or higher and anything less would be an issue.
Willcox
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,112
From: Crossville TN
Ignition coil "resistance" values are resistance measurements for primary and secondary windings in the coil. They do not include the external resistance when making those measurements.
The coil may state that it is for "external resistance" ignition systems, but that has nothing to do with making coil resistance checks.
The coil may state that it is for "external resistance" ignition systems, but that has nothing to do with making coil resistance checks.
Last edited by 7T1vette; Sep 18, 2016 at 02:03 PM.
Burning Brakes
Joined: Apr 2008
Posts: 1,222
Likes: 93
From: shelbyville West Michigan
a few seconds typing in the item to Advanced auto's website reveals the following (you're welcome):
CARQUEST by BWD Ignition Coil
Part No. E40P
The ohm rating of the primary resistance is 3.25-3.50 and the secondary resistance is 7700-9500
specifications:
Connector Gender: Female
Contains Internal Resistor: No
Contents: Ignition Coil
Mounting Location: External
Number of Terminals: 2
Number of Volts:12
Requires External Resistor: No
Terminal Gender: Male
Terminal Type: Stud
CARQUEST by BWD Ignition Coil
Part No. E40P
The ohm rating of the primary resistance is 3.25-3.50 and the secondary resistance is 7700-9500
specifications:
Connector Gender: Female
Contains Internal Resistor: No
Contents: Ignition Coil
Mounting Location: External
Number of Terminals: 2
Number of Volts:12
Requires External Resistor: No
Terminal Gender: Male
Terminal Type: Stud
Last edited by gungatim; Sep 19, 2016 at 09:31 AM.
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Tech Contributor
Joined: Jun 2004
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
), the (maximum) primary current [13.2v/3.25Rcoil=4.06A] is slightly less than the original setup, using the numbers from Wilcox [13.2v/(1.5BR+1.5Rcoil)=4.4A or 13.2v/(1.5BR+1.7Rcoil)=4.125A], so coil primary current shouldn't be an issue for the points.I don't recall if the question got answered before, but are you confident that the condenser is not damaged or defective?
Racer
Joined: Sep 2019
Posts: 349
Likes: 44
From: Spokane, WA
You didn't say what year the car was, but I ran the part number and I'll assume it's a 1974 or older car.
What problem are you having to check the new coil?
Normal resistance would be around 1.5 to 1.7 on the primary side. On the secondary side with your meter in the 20K setting you should read 11.0 or higher and anything less would be an issue.
Willcox
What problem are you having to check the new coil?
Normal resistance would be around 1.5 to 1.7 on the primary side. On the secondary side with your meter in the 20K setting you should read 11.0 or higher and anything less would be an issue.
Willcox