No spark

Question Description

85 BMW 538 I     No spark from coil to distributer ?

Final Answer

if you run into any spark issue. start the most obvious beginning, ignition coil then to the dizzy then other components.

if the primary & secondary resistance on the ignition coil is out of spec, it is bad. get a new one. the specs should be in the bentley

primary resistance
TCI system (which was my car) .82 ohms
motronic .50 ohms

secondary resistance
TCI system 8250 ohms
motronic 5000-6000 ohm

my ignition coil was the culprit.

put a spark plug in a plug line that is connected only to the ignition coil. ground the spark plug and crank the car. if no spark, then proceed to test the ignition coil's resistance. if out of spec, need to be replaced.

The distributor directs 'bursts' of high voltage to one lead at a time. There isn't a constant voltage to each plug.

Did you mean continuity?

I'm not familiar with the particulars of the m10 ignition system, but basically, you aren't checking for current to the plugs, at least in a traditional sense. You want to check that the coil is firing, and the distributor is properly sending that voltage through the cap and rotor, down a spark plug lead, and through a spark plug, causing it to arc.
Disconnect a spark plug wire from a plug, remove the plug from the cylinder head, and then reconnect the plug wire to the plug with the plug not threaded into the head. Lay the plug somewhere on the engine where metal on the plug is touching metal on the engine (but don't hold onto it with your hands) while a helper cranks the engine.
If the spark plug is arcing with the engine spinning, then the issue is either timing related, or unrelated to the ignition system altogether.

duingpung (540)

Thanks for the help.

Outstanding. Studypool always delivers quality work.

Tutor was very helpful and took the time to explain concepts to me. Very responsive, managed to get replies within the hour.


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