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I have no spark

  

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I have a 1993 Honda prelude with a f22a1 engine it cranks but doesn’t start I checked everything like compression, air, fuel and timing everything is fine but it doesn’t have spark I’ve changed the distributor, cap and rotor, external coil, fuel relay, checked all the fuses and even changed the ecu still nothing. Any suggestions


2 Answers
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Hi Tony. I think Scotty was referring to an Open (break) or short in the wiring between the ignition switch and the coil/distributor.

You have a lot of new parts including a new coil.

That new coil only needs 2 things to produce spark. Power and a switched Ground so maybe the 1st thing to do is to determine which of those 2 is missing.

Once you determine which is missing you can investigate that side of the circuit.

You said your Honda has the externally mounted ignition coil (not inside the distributor)

Here's the circuit:

1) Pull off the high tension wire from the coil that goes to the distributor cap. Check for spark at the coil as you crank the engine.

If you aren't getting spark from that brand new coil then check for power and the ground switching signal at the coil wiring connector.

The Positive side of the coil gets power from the yellow and black wire from the ignition switch. That also provides power to the igniter.

2) Grab a test light. Attach the test light's alligator clip to battery ground.

KEY ON, touch the test light's probe to the ignition coil connector terminal with the Yellow and BLK/YLW wires.

If you have power there, then the ignition switch, fuses, relay, and wiring on that side of the circuit are all good and you can move on to the Ground switching signal.

If it doesn't light up then you have to troubleshoot those things.

3) Move the test light's alligator clip to the Positive battery terminal.

Have somebody crank the engine as you touch the test light's probe to the ignition coil connector terminal with the BLK/WHT wire.

The light should flash on/off as the Ground is being switched on/off by the igniter.

So one of those two are going to be missing. Either Power or the Ground switching signal to the ignition coil.

 

If you aren't getting the Ground switching signal, one more thing you can do to narrow this down is to check the Ground switching signal at one of the fuel injector's connectors.

Same drill. All 4 fuel injectors share the same power source and the power wires to all 4 connectors will be the same color.

The Ground switching wires will be different colors on all 4 fuel injectors. Those are the ones you want.

So, the test light's alligator clip still on the Positive battery cable, have somebody crank the engine as you touch the test light's probe to the Ground terminal of one of the fuel injector's connectors.

If it flashes on/off that tells you that the distributor is turning and that the pickup coil (Hall sensor) is providing the same signal to fire the injectors as it uses to fire the coils.

That would narrow it down to the igniter/igniter wiring and connections.

So,

1) test for power at the coil

2) test for Ground switching signal at the coil.

3) if no Ground switching signal at the coil, test for Ground switching signal at a fuel injector.

Let us know what you find out

 

 

 


1

Well if you still have no spark after replacing the distributor I would assume there's a problem in the wiring between the ignition switch and the distributor. Check for power loss to distributor when you turn the key on


I checked the ignition switch voltage black/yellow and black/white wire and they both fall to around 9 volts is that normal? The white and white/black stay around 11 to 12 volts


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