Engine cranks, but it won't start (No Spark)

[TheCrazySwede]

I have a 1977 280z and I'm having some trouble getting it starting. I don't seem to get spark from any of my plugs. The car was working fine the other day, but suddenly decided not to work. I've had starting problems in the past, but I have been able to fix them with some good ol' starter fluid. That trick won't work this time. The engine cranks just fine (starter gets proper voltage, as well.) I've checked the battery and the connectors, all work fine. I replaced my ignition coil, and all of the wires (ignition wire and spark plug wires) and I've also replaced the plugs, themselves. Still, no spark. I checked the resistance of my distributor cap and I got around 0.9 to 1.2 ohms. I believe it is suppose to be near 0, but I don't know if my level of resistance is enough to prevent the car from starting.

My main question is this; Are the possible issues in the distributor, the cap and the rotor? How could I accurately test each one? (I've searched Google, but I've fond a ton of different answers that are totally irrelevant. Maybe I'm not looking correctly.)

What else could be causing this?

Thanks guys, I really appreciate it. Cheers!

[EuroDat]

Have you downloaded the fsm and gone through the trouble shooting section? http://www.xenons30.com/reference.html

Sounds like its in the electronics in your distribitor or your not getting power to the coil.

I take it its just ohms and not 1.2k ohms? The resistance over the distribitor cap and rotor button is not your problem then. You can check it by pulling the coil lead out of the distributor and use a spark plug to see if your get spark there.

Good luck with it.

[TheCrazySwede]

Thanks for the reply EuroDat, I really appreciate it.

I did download and read the FSM, but it didn't help me with much. I looked through my owner's manual and my symptoms fall under a bad ignition system, so I'm trying to trace down the problem from there. Yes, measured in just ohms.

Hm, I have yet to try that. So, I can just take the ignition wire from the coil, disconnect the end connecting to the distributor and use a plug in its place? Didn't think of doing that! Surely, it will help in finding out the problem. If no spark occurs even then, it can't be my distributor or dist. cap, right? Heck, they might be a goner, too :S

Can a faulty Ignition Module cause this? I've always heard of people having their car die on them while driving, then working just fine. That has never happen to me, so I doubt that's the case.

I really appreciate the help. My 280 is my first car, and so I'm still in my learning phases of things. It means a lot, thanks.

[EuroDat]

You dont need the dist. cap or the rotor button to do that test. Just use the HT lead from the coil to an old spark plug and crank the engine. I dont think the problem is in the dist.cap or rotor button.

Its probably in the pickup under the rotor button. It has two wires (red and green) they go to a terminal block just in front of the coil. Check that nothing is loose and disconnect.

Then the wiring to the coil. Check the resistor under the coil. It could be your problem. Are your getting power to the resistor?

EuroDat (Chas)

[tamo3]

basic test for spark plug.

Does this help?

[EuroDat]

OMG. Thats the Mechanics version of Ty from Extreme home makeoverLOL

[TheCrazySwede]

You dont need the dist. cap or the rotor button to do that test. Just use the HT lead from the coil to an old spark plug and crank the engine. I dont think the problem is in the dist.cap or rotor button.

Its probably in the pickup under the rotor button. It has two wires (red and green) they go to a terminal block just in front of the coil. Check that nothing is loose and disconnect.

Then the wiring to the coil. Check the resistor under the coil. It could be your problem. Are your getting power to the resistor?

EuroDat (Chas)

I tried the coil test with the spark plug, and I got no spark

I checked the wires from the rotor button, and everything was in good condition.

I also checked the resistor and I'm getting power to that, as well.

Not really sure what else to look for :/

I really appreciate the help guys. It truly means a lot!

[ZCurves]

Check/Replace your Ignition Module, you can find new ones on ebay / rockauto. That's why my Z was giving me intermittent spark. If your coil is original, you could also replace that with a current MSD or Accel coil, although my coil was working - there was a noticeable jump in the Tach needle from something. New Coil, No Jump.

See my other post here:

http://www.classiczcars.com/forums/showthread.php?t=47690&p=414523&viewfull=1#post414523

Edited November 9, 2012 by ZCurves

[EuroDat]

If you want to play around with it, you can try these checks:

Check the coil resistance. CHeck the resistence over the two terminals. Should be less than 2.0 ohms for OEM coils.

Check the air gap between pick-up and the reluctor. Should be 0.2 to 0.4mm. If the gap is to wide the pick-up will not read the reluctor and no spark.

Check the resistance in the pick-up. Mine is 730 ohm. Im not sure but I think the spec is 700 to 740 Ohm. You can measure it from the terminal block just in front of the coil.

Your getting power to the resistor, but are you getting it at the coil. You can disconnect the + wire from the coil (white with black strip) and check if your getting power there.

If this all checks OK. Then it looks like its a problem with the transistor unit or the wiring to it.

Connect a voltmeter to the - side of the coil and ground on the car. Turn ignition on. Check if you see battery voltage. If so move onto the transistor unit.

Checks at the Transistor unit: Its located at the passengers side under dash.

Disconnect the plugs and do the following tests.

Check if its getting power. That is the Black wire with white strip and the black wire on the small plug. They should have battery voltage. The long plug has a power wire as well.

Check the resistance between the green an red wire from the pick-up. Should be the same as before at the terminal block in front of the coil.

Remove the plug to the cold start valve so you can crank the engine without pumping to much fuel in it. Set you multimeter to AC voltage as low a scale you can go and crank the engine. You should see it bump a little. It won't be much, about 0.5volts, depends on your meters response. Every time the reluctor passes the pick-up it will pulse.

Good luck

Chas