ArthurDent
ArthurDent Reader
2/25/12 12:39 p.m.

This is driving me crazy - I can't get my spark plugs to fire on my Nissan Micra.

Here is the story - can skip this if you want - car drove great for almost two months when my insurance company insisted on a safety inspection. I don't know a good mechanic so I just took it somewhere. They BS'd me with the usual needs rear wheel bearings repacked and replaced a ball joint. Took a week to do it as well. Fine - I got ripped off but that is the usual fare for safety inspections sadly. Now here is the issue on the way home the car stalled at the traffic lights a couple times on the way home - never done that before. I get home and fine but it has never started since. I can't prove they did anything and it is an old car but the timing is awfully suspicious. Damned if I am giving them $100/hr to look at it though.

So I determine the spark plugs aren't firing. Replace the plugs since they are old and nasty. Nothing. Replace rotor and cap. Nothing. Use a set of known good spark plug wires. Nothing. Get coil from the scrapyard. Nothing. Replace coil with brand new unit. Nothing. Argh. What the heck.

Engine turns over, distributor turns, power to coil. But no spark plugs fire. What the heck? Any ideas?

ArthurDent
ArthurDent Reader
2/25/12 12:52 p.m.

I should add - I've got almost new battery charged up.

The car is a carb'd four cylinder with an electronic coil. I have a junkyard spare coil with a spare set of the electronic bits. Made no difference.

1989 Nissan Micra 1.2L engine

mad_machine
mad_machine SuperDork
2/25/12 1:09 p.m.

did the trigger wheel for the electronic ignition die? It probably uses a hall effect distributer?

Streetwiseguy
Streetwiseguy SuperDork
2/25/12 1:19 p.m.

Congrats on diagnosing the ignition system backwards... Ok. Key on, there should be 12 volts on both sides of the coil. If you crank the engine, one should stay 12v (that would be the power supply) and the other should flash a test light. That would be your ignition module firing the coil. If the test light flashes but you have no spark, you have a secondary ignition problem- coil, rotor,cap,wires...seems you have that covered.

The negative post of the coil, which is the one that should be flashing, will either have 12V constant, or be grounded. If 12 V constant, follow the wire to the distributor or igniter or module, and make sure its not broken or disconnected. If grounded, make sure the wire isn't rubbed through, then unplug that wire at the distributor/module/igniter. If its no longer grounded, get a new distributor/module/igniter.

Long story short, you need to inspect all the wiring for breaks and grounds, then buy a new igniter or distributor pickup.

Oh yeah- is the camshaft turning?

ArthurDent
ArthurDent Reader
2/25/12 3:05 p.m.

Thanks - I figured I'd do the tune-up stuff anyway

Ok here is my coil - it doesn't have the exposed posts though. If unplug the cable and turn on the ignition I've 12V on the black/white wire and nothing on the blue. So I believe blue is negative.So that seems ok. So if I piece the blue wire with a test probe and crank it should flash then I guess.

coil

Streetwiseguy
Streetwiseguy SuperDork
2/25/12 3:52 p.m.

In reply to ArthurDent:

Yep. That blue wire will run to the igniter. The igniter is triggered by the pickup in the distributor.

ArthurDent
ArthurDent Reader
2/25/12 4:41 p.m.

Out so I unplugged that from the coil, connected test light to blue wire and cranked. No flashing. From what I can tell online my ignitor is built into my coil module. Perhaps that box next to it? I sourced that junkyard one of those.

The manual I have is no help as it covers the earlier and UK models but not my Canadian ignition type.

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