crank but no spark after engine swap

[Angie]

glad to hear you are making progress. this is what i was thinking, something isn't plugged in or you may have over looked something. as ron said, these engines are fairly basic in the spark no spark. cheers and happy hunting.

 

[alwaysFlOoReD]

I had a problem with no spark. After several months of sporadic detective work, I found one of the plugs not making proper connection. Turns out the little orange rubber o-ring inside the connector was preventing full connection. A little dielectric grease cured that...

 

[sam klassen]

I had a problem with no spark. After several months of sporadic detective work, I found one of the plugs not making proper connection. Turns out the little orange rubber o-ring inside the connector was preventing full connection. A little dielectric grease cured that...

That's the orange oring in the connector to the coil?
And dielectric greace gives a better connection?

 

[alwaysFlOoReD]

It wasn't a coil connector. It was one of the bigger ones carrying 12 or more wires. It's been almost a decade so memory isn't clear. But the rubber o-ring is inside the connector to prevent water intrusion. It dries out and makes it hard the push the connectors together. I'll assume that there must have been a wire in that bundle that was part of the spark circuit.

 

[sam klassen]

how do you test the coil on this? and is there anyway to see if the icm is sending a ground pulse maybe a scope?

 

[RonD]

Put test light in coil's 4 wire connector's 12v wire(red one) and any one of the other 3 wires(the grounds)
Crank engine over, light should flash if "ICM" is pulsing ground


Plug in 4 wire connector to coil pack, hook up spark "tester" to any spark plug wire
Key on
Unplug 4 wire connector
Should get a spark if coil is working and powered up


All ignition coils work(spark) by cutting voltage, 12v or ground, ground is cut because its simpler and came from using points in a distributor
With Key on 12v is at the coil pack and "ICM" grounds all 3 wires to "charge up" the 3 Primary Coils
If you unplug the 4 wire connector that cuts 12v and ground so coil's Secondary coil releases it's "charge", so sparks

 

[sam klassen]

Can I use a multimeter and use the ohm setting to see if those grnds are being grounded

 

[RonD]

No, digital meters won't react quick enough, analog meter will show voltage pulse

Cranking speed is 200rpm
Each coil in the pack sparks once each rpm
So with Waste Spark there would be 200 pulses each minute, so 3 pulses each second
Digital meter would just show steady ground or steady 12v

Test light would flicker, analog meters needle would as well

 

[sam klassen]

So let me try to understand the icm it is grounding the coil correct? Is it when it gets grounded it sparks ok when it stops being grounded it sparks

 

[RonD]

When its unGrounded it sparks

When the Primary coil, inside an ignition coil gets 12volts and a ground it creates a magnetic field around the Secondary coil
The Primary coil just has a few windings(coils of wires)
Secondary has 1,000 times more windings

So the 12v becomes 12,000v in Secondary coil(low amps but high volts, its not creating "power")

When Primary coil's power is cut, either the 12v or the ground, the Primary's magnetic field "holding" the 12,000v in the Secondary coil collapses and the 12,000v is released, the spark

General description, if you are interested in exact numbers Google it


In general the reverse happens on AC voltage distribution
Wires on the poles outside carry 12,000vAC, transformers on the poles change it to 120vAC to be sent into your house
Just FYI

 

[sam klassen]

Thank you

 

[RonD]

So just need to power up any ignition coil then unpower it and it will spark............if its working

Also the CEL, check engine light, should come on with key on, means computer has booted up
And CEL should go OFF when cranking engine over to start, means computer is getting a valid crank sensor pulse, from "ICM" in this case(1994 computer and "ICM")

 

[sam klassen]

The cel goes off then comes back on then if I try again without turning it off it stays on is that bad?

Would an oscilloscope be able to pick up these ground pulses.

 

[sam klassen]

I can check for continuity from the 3 grnds from the icm to ground?

If so I don't get any.

 

[sam klassen]

ok my coil is good i grounded the yellow red one ungrounded it and spark

what else do you think it is the icm? you had said that the engine cranks around 200rpm right. so i should be able to see that on the, whats it called tachometer? so i looked and it moves a tiny bit like you can barly see it move.