[greg007]

Hello everyone, i have a VW cabrio 2001 and the ignition coil keeps on burning out. I have changed more than 7 times in the past year. I changed the spark plugs, wires, and air filter. Still didnt help. What could cause it to burn it like that? Sometimes when i turn the key, the car would take about 3 seconds to crank but not often. I have taken it to different shops and they cnt find why. Could the starter be the cause?

Thank you

 

[vicrod]

dealer

This following is a general response to the question.
Are you sure the correct coil is being used?
How are you testing the coil to determine that it is burned out?
Somewhere is the coil primary circuit (the 12 volt part) a current limiting device is needed. The coil itself may provide it's own current limiting. Assuming the coil is not faulty, to much current will burn out the coil.
Check to make sure all factory VW components are installed. And get a coil from VW dealer. :evil:

vicrod

 

[greg007]

There is no spark coming out thats how i check the coil. I bought one from the dealer and it lasted longer than the other ones about 4 months. I think it is the coil because when the car does not start, I just change it and it works. Also the coil be hot. But i don't know why it is burning out

 

[vicrod]

heat

Try going to the Autozone repair help website. There they explain how to diagnose the problem.
That year car had some different engines and ignition systems and they seem to be covered by this site.
The module that fires the coil may be at fault because it is sending to much current to the coil. This explains the short life of the coils.
Also the mounting of the coil may be an issue as heat is not being removed, allowing the coil to overheat.

vicrod

 

[greg007]

Hello Vicrod, thanks for the help you've been providing me.
I was checking the grounding system today in my 2001 cabrio. I realized that the grounding cable that goes from the valve cover to the ignition coil bracket was really bad. I taped it very good. If this ground is bad, could it cause the ignition coil to burn?

Thank you

 

[timothale]

some tips

on older points type cars. leaving the key in the run position and IF the points were closed it could start overheating the coil. The bad ground is probably the problem, there are two circuits in a coil , the primary and secondary windings both have to have a good ground to work., on a points car the primary ground was thru the points, the secondary (spark ) circuit was thru the case, With a bad ground that circuit tries to ground somewhere else, put a feed back current where it shouldn't go. a bad condensor used to also cause problems. When the spark occurs that collapsing magnetic field induces a current in the primary windings, that then puts a small amound of voltage back into the secondary, that would repeat until it died down, It only took a milisecond, On an osciloscope you would see the wiggles tapering down after the spark patern. There could be a bad component inside the ignition module. Does it have a good ground. ?

 

[greg007]

Thanks for you help. The ignition module and the coil come as a unit when you buy ignition the coil. I don't know if there could a bad ground there. How many volts the coil is supposed to receive and put out please? It seems that the one I bought is a 9 volts which causes it to burn since it receives i think 12 volts from the battery.


Thank you everyone for your help

 

[timothale]

don't know

My only VW is the engine in my dune buggy, an old 40 HP.

 

[LATECH]

The module that fires the coil may be at fault because it is sending to much current to the coil. This explains the short life of the coils.

vicrod

I am thinking Vicrod is on to something. Many of todays PCMs have an "active dwell " configuration in the software that fires the coil.
If you have an old dwell meter, hook it to the coil and see what the dwell is at Idle, at 2000 rpm and at 4000 rpm. Chances are the dwell will increase at all rpms as you go up. This is due to the active dwell component in the PCM.
If dwell is too high at low rpm , the coil stays energized too long, overheats, and will burn out.

You should just go over to the VW place and tell the service manager your problem, chances are he will know what the problem is. Its a good chance that a software upgrade will fix it.

 

[vicrod]

just a theory

See here's my theory.
All these wonderful nerds that design this crap really don't understand or care about the long term issues. Their bosses are completely clueless, the crap is not tested or pier reviewed. The crap gets into production and its amazing how much of it actually works.
Case-in-point Toyota acceleration issue = $1B settlement. Oh no, we don't need a backup system, that would cost us $1 per unit (car). Can't waste money on that crap.
I rest my theory. Not.

vicrod

 

[timothale]

Toyota software

Toyota never did release all the software to be analyzed, When I was an engineer at Ford I did the logic parameters on a complicated car storage system, If you ever are at The Great Mall in Milpitas Calif, (The old Ford Mustang and Truck factory), you will see the 10 story tower, It was used to store up to 40 painted truck cabs and beds, that could be retreived to be matched to the optimum build order down the assembly line. The problem in the tower was an electric eye could get out of alignment or a limit switch malfunction and the computer would think a cab space was empty, and crash stuff together. When I designed the control system for the Car storage system I made the guy writing the software do yes- no safety check loops. It took about 3 times as many lines of code but new mustangs did not crash into each other. From what I understand of the Toyotas There was no safety verication checks in the code to check that all the components were still working corectly and input was logical. Out Electrical Tech became and expert on conveyor system logic and was an expert witness when a couple deaths occured at an ammusement park ride. A broken wire or faulty electric eye made the computer think a space was empty and the next ride crashed into passengers.

 

[vicrod]

failure

Some industrial designers take their examples from the old school approach that everything has a failure mode.
What happens when xyz fails. Let it fail safe, fail on, fail off or other.
What happens when you are driving down the highway at 70 mph and you let off the throttle pedal but it does not release and slow the car. So you hit the brake pedal and the throttle still does not release?
Now where is the backup system? The computer is useless no matter how much code is stuffed into it.
Turning off the ignition? Computer.
Hit the brakes? Computer has a code for this conflict. Computer is broke.
An example in this case would be a simple extra set of contacts in the brake light switch/circuit that can interrupt the throttle actuator.
At least we still have hydraulic brakes that are directly piped to wheel cylinders, right?

vicrod