need help please - engine died will not start - i am at wits end

[c6fan]

Sitting at a stop light last night and the engine stops running, it will not restart despite turning over fine.

Car 71 240z

engine L28

round top ztherapy su's

Electronic Z distributor w/E12-80 ignition module

Upgraded alternator with internal voltage regulator

electric fuel pump

5 speed

Car was running fine, alternator charges appropriately and has plenty of gas, I am getting no spark to the plugs.

Last night I swapped in my 2 separate e12 modules (kept in car as spares) did not work, had car towed home. Today I checked the fuel pump it is working and the carbs are getting gas - no spark at plugs. Here's what else I have done so far:

Swapped coils with a known good one out of a running car

Checked fuses, none blown

verified fusible link is good

cleaned all connections on battery, starter, coil, ignition switch connections

cleaned dist cap and rotor

swapped in new ignition switch

Battery has plenty of juice, car turns over great but no spark to plugs, coil is getting power

out of desperation tried spraying starter fluid just to make sure

I guess it is remotely possible that all 3 of my modules are bad but that seems unlikely. This is driving me crazy does anybody have any ideas, what else can I check/replace/beat with a hammer?

Thanks in advance for any input,

Doug

[Zed Head]

I would check for power to the E12-80 module, check the ground from the distributor body to the block/negative post, and open up the distributor and make sure the stator magnet hasn't broken.

If you have power where it should be, and ground, and the modules are good, then the main thing left is the signal from the VR coil. I haven't been in to a ZX distributor so don't know exactly how the six pointed wheel generates the pulse, but the module won't trigger unless it gets the voltage pulse from the magnetic coil. There is probably a test for the it in one of the ZX FSMs, Electrical section.

I've seen several broken magnets on ZX distributors in the wrecking yards. Typically, there is also play in the rotor, allowing it to touch one of the "points", probably shocking the magnet assemblyand breaking it (my WA guess).

Here is a link to a picture of what I'm talking about - http://www.oreillyauto.com/site/c/search/Ignition+Pickup!s!Stator/C0417/C0334.oap?year=1982&make=Nissan&model=280ZX&vi=1209350&keyword=ignition+pickup!s!stator

If it doesn't work, just search ignition pickup stator on one of the auto parts store sites, for a 1982 280Zx.

Edited November 22, 2011 by Zed Head

[beermanpete]

I agree with Zed Head. Check the resistance of the pick-up coil with an ohmmeter. Look in the service manual for the year model your distributor is from. It will have a specification for the DC resistance of the coil.

[c6fan]

Thanks guys, I borrowed my neighbors multimeter and will be testing tomorrow. Cheers.

[c6fan]

The distributor and ignition module check out fine. Pick up is working and sending signal out from the ign module. However I was out working on it tonite and I noticed that when I turn the ignition on the running lites and gauge lites come on. Very curious. So I unplugged the power line to the coil and ran a wire from the battery direct to the coil so I was bypassing the ign switch. As soon as I hooked up the wire to the + coil terminal from the battery pos terminal the running lites etc came on again. WTF is going on here? Somehow the parking lights circuit is being energized from the ignition circuit. Clearly this has to be related to the problem of no spark.

Go from car running fine to this, I am truly perplexed now.

[Zs-ondabrain]

So you told me you unplugged the Parking light upgrade and returned everything back to stock, right? And the Parking lights still come on with the ignition? yup, that's weird.

I would check the fusebox for melting or solder problems. I'm trying to think of where else the parking lights and ignition are crossed. Thinking..... Thinking....... Nothing yet but I'll get back to ya.

[Zed Head]

Actually it sounds like you might have a short circuit from the negative side of coil circuit to the running lights circuit. If that is the case, power would always flow through the coil to the running lights, the coil-charging circuit would never be broken and the spark would never happen. The short could be anywhere from the negative side of the coil to the ignition module over by the fuse box.

It could also be the wire to the tachometer, and Pin 1 on the ECU, since they both have a branch off that line also. The wires from the negative side of the coil are blue. Wiring diagrams are in the FSM.

That would be a new one. Good luck finding it.

Edit - I was typing while Zs-ondabrain was posting...

Edited November 26, 2011 by Zed Head

[Zed Head]

Double.

[Zs-ondabrain]

Wait!! Unplug the headlight switch and try again. If the lights still come on with the ignition, the we can eliminate the fusebox and switch as a problem.

Try that and let me know....

Also, The lights are likely taking the power from the ignition (to the coil and dizzy) and the "Unfound" short is robbing your spark.

Unplug the Larger 4-pin connector on the passenger side inner kick panel that has a Green/blue wire (it also has a red, red/yellow and red/blue wire in that connector) When it's unplugged, try the ignition again, does it still light up the parking lights? If it lights up the Outer parking lights with the ignition, then the short will be easier to find in the engine compartment.

If the ignition lights the dash lights only with that plug unplugged, then the short is in the dash.

Dave

[Zed Head]

Just realized that you could also disconnect the negative post of the coil. If the lights stay on, the short is on the positive side (and negates my proposal), if they go off, it's on the negative side. Gets you closer.

[c6fan]

Actually it sounds like you might have a short circuit from the negative side of coil circuit to the running lights circuit. If that is the case, power would always flow through the coil to the running lights, the coil-charging circuit would never be broken and the spark would never happen. The short could be anywhere from the negative side of the coil to the ignition module over by the fuse box.

It could also be the wire to the tachometer, and Pin 1 on the ECU, since they both have a branch off that line also. The wires from the negative side of the coil are blue. Wiring diagrams are in the FSM.

That would be a new one. Good luck finding it.

Quite sure you're right, it is the neg side shorting somewhere which is preventing the fire signal from reaching the coil. Been tracing thru the wire diagram, no ecu on my car though.

[Zed Head]

Oops. Didn't re-check the details of your setup. At least the E12-80 ignition module is close, on the distributor.