voltage at coil but no spark...

[78280z]

I have no spark at the plugs, so I moved back to the coil to see if I have spark coming out of the coil. I have voltage at the coil, but when I take the wire that goes from the coil to the distributor off the distributor and try to create an arc between it and the frame, it does not arc. Anybody have any ideas?

[alexideways]

Either the coil or igniter are bad or whatever (I say whatever cause, you didn't specify what ignition your car is using but, from your screen name, I'd say your car uses a pick up coil & reluctor) is supposed to trigger your primary isn't working. Check the pick up coil's signal lines between the distributor and the igniter and the line between the igniter and the neg. side of the coil.

Also check if your igniter is getting power.

Also check for continuity in the pick up coil...

 

Check for continuity trough both stages of your coil and also check their resistance...

 

For the primary, you should get something between 0.45 & 0.55 Ohms

For secondary, you should get a reading between 8.5 & 12.7 Ohms

 

If your car is equipped with the stock coil...

[Kevin Shasteen]

There are only a few items to note when you have a no voltage issue, and they are:

 

1) Ignition Switch (this is the switch activated when you turn the key cylinder and it is attached to the back side of the ignition key cylinder)

2) Ignition Relay (this relay is activated when you turn the key cylinder and this switch then activates your electronic ignition control box - which further activates the coil)

3) Ignition Coil / reluctor (as said in #2, ignition coil is activated by the elec.ignit.box and this allows the coil to fire the plugs and engine starts when starter turns)

4) Wiring in between these sources

5) fuses that looked good but were bad (specifically the fuse that powers the ignition relay: if memory serves me correctly)

6) Fuel Injection Relay, Fuel Injection Harness Realy (if there is a problem with the fuel injection relay or within the fuel injection harness - these relays will shut off power to the ignition control box thus shutting off the electronic fuel pump.

 

 

The coil is the easiest to test. If you are not sure how to check it-take it off (noting which wires go where) and take it to your local auto parts store to be tested.

 

I always make sure I have a good 12volt coil handy to swap out if and when I experience an engine turns but doesnt start scenario where I'm not getting fire to the plugs.

 

On my 78z I had two problems with mine. I had an intermittant no engine turn when key was turned and then I also had an intermittant engine would turn over but wouldnt start.

 

The problems turned out to be bad fuses, ignition relay that would work some of the time, and then a weak coil. Sometimes a cold coil will test good but once it warms up it will test bad: so when in doubt just replace it.

 

The coil is $25 to $35 depending on brand name, the ignition relay is $35 to $40 from Nissan. The Ignition control box is like $300 from Nissan and has switches in it that when you first turn your ignition key switch to the on position will power up the control box which powers up the coil which prepares your starter to turn the engine to be fired.

 

Now, if the control box is bad it could be turning your ingnition off when the key is turned from the on to the start position.

 

You could test this with a test light while someone else turns the ignition key from on to start. Place your test light on the negative terminal of the coil when the key cylinder is turned to the on and start position. Then place your test light on the positive terminal of the coil when someone else turns the key cylinder to the on and start postition.

 

You could also test the electronic ignition control box by taking it off and taking it to the local auto parts store to be tested on their relay machine. This control box is black (if it is original) and found in the passenger kick panel just fore of the fuse panel: it has two 10metric screw/bolts holding it on.

 

The ignition relay is found just above the fuse panel with the other relays. Check your repair manual to know which one is the correct one.

 

The fuel injection relay and fuel injection harness relay are found in the engine compartment under the curved metal on the inner fender next to the battery. They are hidden to the eye unless you remove the curved metal covering. To test these you will need someone w/experience or a factory service manual to tell you how to go about testing them.

 

One way to know if/when your fuel pump relay and fuel injection harness relay are/or are not working is to jack the rear end up where you can gain access to the fuel pump. Once you have the car jacked up (always use jack stands w/the floor jack) place your hand on the fuel pump while someone turns the key switch to the start position.

 

You should be able to hear the pump's low humming. If you can't hear it you should be able to feel the vibration of the pump once it is activated. If the pump doesnt come on then one of the relays in the chain of command have not been activated for one reason or another.

 

Good luck, sorry to hear you are having these issues (I hate no start problems).

 

Kevin,

(Yea,Still an Inliner)

[78280z]

Thanks for all of the suggestions! I've got some troubleshooting to do!