when your coils going, would it cause spark to work sometimes? or does it just work that when it starts to die, just stop working insted of giving a weak spark. whats the setting i use on the multimeter to test and can i use a normal bosche coil or do i have to use a blue bosche coil? there isnt a shop that knows how to work on a series engines within 5 hours of me, so any help would be greatly appreciated.
No Spark Help. Coil?
Started by
plunger
, Dec 27 2007 05:26 AM
1 reply to this topic
#2
dklawson
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- TMF+ Member
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- 10,923 posts
Moved Into The Garage
- Name: Doug
- Location: Durham, NC - USA
- Local Club: none
Posted 27 December 2007 - 02:58 PM
Hello and welcome. I'm sorry your first post has to be regarding problems.
You've asked several questions and I'll try and respond succinctly. However, first let me also direct you to a PDF I put together for points ignition systems.
http://home.mindspri...tsIgnitions.pdf
The Bosch Blue is a 12V "standard" coil. It will have a resistance of about 3 Ohms across its primary windings. To measure this you LABEL, then remove, the low-tension wires on the spade lugs and measure the resistance across the spade lugs with your meter set to a fairly low range. (You need to disconnect the wires during measurement as attached components can significantly alter the resistance readings). Again, you should see about 3 Ohms. However, this will only confirm if the windings are intact and it will confirm what I've already told you about the resistance being 3 Ohms... it won't tell you if the coil is good or bad. Coils are often blamed for problems that lie elsewhere. When coils DO go bad, they typically show problems after the engine has been running for a while and the coil gets very hot OR the problems show up at high RPM.
You asked which coil you use. Over the years the Mini used both "standard" and "ballast" ignition systems. On a standard ignition system the coil is fed power from the ignition switch using a white wire, there is no external resistor. On cars with ballast ignition systems, there is a wire running from the starter solenoid to the coil (+) terminal and the coil is typically fed from the ignition switch using a "pinkish" resistor wire. You'll have to look at your wiring to determine what you have.
Before you decide you have coil problems, start by dressing, re-installing, and resetting the points in the distributor. If you have a dwell meter, set the points that way, not using feeler gauges alone. While you're working on the points, replace the condenser. It's fairly common for points wear to make the points gap close prematurely... resulting in an engine that won't start or won't run. Likewise, a failing condenser can act like a kill switch and prevent spark. Both are less expensive to replace and more likely culprits than the coil.
You've asked several questions and I'll try and respond succinctly. However, first let me also direct you to a PDF I put together for points ignition systems.
http://home.mindspri...tsIgnitions.pdf
The Bosch Blue is a 12V "standard" coil. It will have a resistance of about 3 Ohms across its primary windings. To measure this you LABEL, then remove, the low-tension wires on the spade lugs and measure the resistance across the spade lugs with your meter set to a fairly low range. (You need to disconnect the wires during measurement as attached components can significantly alter the resistance readings). Again, you should see about 3 Ohms. However, this will only confirm if the windings are intact and it will confirm what I've already told you about the resistance being 3 Ohms... it won't tell you if the coil is good or bad. Coils are often blamed for problems that lie elsewhere. When coils DO go bad, they typically show problems after the engine has been running for a while and the coil gets very hot OR the problems show up at high RPM.
You asked which coil you use. Over the years the Mini used both "standard" and "ballast" ignition systems. On a standard ignition system the coil is fed power from the ignition switch using a white wire, there is no external resistor. On cars with ballast ignition systems, there is a wire running from the starter solenoid to the coil (+) terminal and the coil is typically fed from the ignition switch using a "pinkish" resistor wire. You'll have to look at your wiring to determine what you have.
Before you decide you have coil problems, start by dressing, re-installing, and resetting the points in the distributor. If you have a dwell meter, set the points that way, not using feeler gauges alone. While you're working on the points, replace the condenser. It's fairly common for points wear to make the points gap close prematurely... resulting in an engine that won't start or won't run. Likewise, a failing condenser can act like a kill switch and prevent spark. Both are less expensive to replace and more likely culprits than the coil.
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