Technical Bad coil?
- Thread starter F30Msport
- Start date
Currently reading:
Technical Bad coil?
lazylobster
Established member
Yes !
How to Diagnose and Test an Ignition Coil
ignition coil,ignition system,ignition,misfire
www.aa1car.com
lazylobster
Established member
Hi, did you not read the web site I posted to you? Details in there, but below for visibility.
To test the ignition coil connect the ohmmeter's two test leads to the coils primary terminals (+ and -). Most coils should read between 0.4 and 2 ohms. Zero resistance would indicate a shorted coil while a high resistance reading would indicate an open coil.
Secondary resistance is measured between the positive (+) terminal and high voltage output terminal. Newer coils with segmented core construction typically read 6,000 to 8,000 ohms, while others can may read as high as 15,000 ohms.
On coils that are not a can style, the primary terminals may be located in a connector or even under the coil. Refer to the vehicle manufacturer's service information for the terminal locations and ignition coil test procedures.
Thanks again. Seems dead.
Would this one fit the bill?
Would this one fit the bill?
For the stock fiat ignition system, you need a "non resistor" style coil. A coil whos primary is more then 2 ohms. Typically in the 3-4 ohm range. Using a coil that is designed to be used with a ballast resistor inline. On the 500, running a ballist resistor style coil without a resistor will burn out the points.
I use a bosch 9220081083, also known as the blue super coil. Its one of the better coils out there. Very common upgrade in the vw bug world. Its a drop in replacement for the factory coil, non resistor type. And is a quality part.
Also known as the Bosch 00012.
Elsewhere you can hop onto rock auto and look up coils for a 1967 vw bug. and see what you find. Those are also the same style -non resistor-
I use a bosch 9220081083, also known as the blue super coil. Its one of the better coils out there. Very common upgrade in the vw bug world. Its a drop in replacement for the factory coil, non resistor type. And is a quality part.
Also known as the Bosch 00012.
Elsewhere you can hop onto rock auto and look up coils for a 1967 vw bug. and see what you find. Those are also the same style -non resistor-
Last edited:
the hobbler
Distinguished member
- Joined
- Jul 25, 2012
- Messages
- 4,374
- Points
- 1,099
I don' tknow what the supply situation is on your side of the pond for "Bosch Blue" coils Jacques,but over here it is dire---I have had one on order for 3 MONTHS, and the supplier has just advised me that they still give an ETA!!! The situation is so bad that I have had to lend my own "Bosch Blue"coil to another 500 owner to keep his car on the road---good job I have gone over to the wasted-spark system!
If coil is proved duff fair enough.
I would say if you are still on points and condensor as original setup, personally I have fitted literally a hundred condensors along with contact breaker points to every one ignition coil. The most frequent cause of an ignition coil failure on a points type system is people leaving the ignition on whilst checking something else and causing the coil to overheat and die! If that is the case it usually does the points and condensor also at the same time.
Re timing issue as has been mentioned not unless distributor was loose. However I have seen the cap fitted badly onto distributor and of course more commonly the HT leads on wrong.
Again on thinking back about coil failure, only one springs to mind , a Ford Mk3 Zephyr four that had an occasional misfire which I could duplicate by banging the coil with my fist as it had a loose/broken wire internally.
Shorting down the neck of the coil due to dirt and damp can give a misfire, but not normally stop it dead.
I would say if you are still on points and condensor as original setup, personally I have fitted literally a hundred condensors along with contact breaker points to every one ignition coil. The most frequent cause of an ignition coil failure on a points type system is people leaving the ignition on whilst checking something else and causing the coil to overheat and die! If that is the case it usually does the points and condensor also at the same time.
Re timing issue as has been mentioned not unless distributor was loose. However I have seen the cap fitted badly onto distributor and of course more commonly the HT leads on wrong.
Again on thinking back about coil failure, only one springs to mind , a Ford Mk3 Zephyr four that had an occasional misfire which I could duplicate by banging the coil with my fist as it had a loose/broken wire internally.
Shorting down the neck of the coil due to dirt and damp can give a misfire, but not normally stop it dead.
Last edited:
internal resistor coil.
Fuel? If you have checked other things I mentioned.
Assuming you do still have points and condensor fitted not after market electronic ignition.
Is it just possible the ignition was left on whilst working or testing starter for more than a short while?
Reason I mention it is it can cause coil, condensor, points or all to overheat and fail.
First have a close look at the points, ideally the contact area should be smooth and clean with no pitting etc.
If when looking at the contact area they are what is described as "blue and pitted" surface that generally means the condensor want's changing along with the points.
The job of the condensor is to prevent "arcing" at the points (basically excessive sparking) which soon knackers the points and will give a persistant misfire.
So once you have a new or good and clean set of points, I always put a tiny bit of high melting point grease on the heel of the cam contact area on the fibre or plastic that rests on the cam lobes opening and shutting the points, the reason for this and a lot of people neglect it, is it prevents early wear of the fibre heel which closes the points gap and causes premature failure. Make sure no grease gets on the point contacts.
Now with the correctly fitted contact points turn the engine pulley until the points are at their widest position open and set it to 15 thousands of an inch gap. Someone will say a "correct " clearance but that is a good starting point and will not be far out.
If you want you can lay the spark plugs connected to their leads on the metal of the engine and get someone to spin it over and you can visually check for a good "blue spark" jumping the plug gaps. Then reassemble and start engine, if all good you may want to check timing using a strobe timing light.
Sorry if over detailed explanation, I first started doing it as an apprentice in 1969
Last edited:
Ok, so I'm going to replace the condenser, but it's ridiculous to buy online and ship for what is about a $4 part. Looking for one at a local parts shop, but not sure what the specs are. Anyone in the US have a suggestion? Hoping to get something at advance auto parts, etc.
Attached a couple pics of the distributor, which I think looks good.
Attached a couple pics of the distributor, which I think looks good.
Attachments
Now, the bosch one has a different plug on the end, but you just need to put a ring or fork terminal end on it.
Have you checked gap with a feller gauge? From the video clip, it seems like it was randomly missing. Which could be too tight of a gap on the points. And to also rule out plugs, have you put fresh plugs in also?
Have you checked gap with a feller gauge? From the video clip, it seems like it was randomly missing. Which could be too tight of a gap on the points. And to also rule out plugs, have you put fresh plugs in also?
