1983 280zX Turbo

The car was running before, but would sputter and stall after it warmed up. Letting it cool off would allow it to crank again and run fine until warmed up again. This problem got worse until finally it won't even start now. It will crank fine and strong, but there is no spark at the coil. I changed the coil and checked for continuity through the harness to both wires going to the ignition control module (YW from pin 5 ECU and BW from the key), and they are fine.

Now I'm thinking it's the ignition module itself, and researching on the web seems to confirm it's a common problem. Looking at the FSM, I cannot tell how to test the module. I see the positive lead of the voltmeter going to the male connectors but I don't see where the negative lead is supposed to go. It looks like it's pointing to the body of the module, but then again the module/coil do not look exactly like what the FSM shows anyway. Anyone know?

Also, is there something else I should be looking at? The AFM registered 194 ohms where the FSM called for 280 to 400, not sure if that's a concern for a no-start condition. CHT is good, checked all grounds I could find. Anything else? Appreciate any help, thanks.

 

Welcome to ZDriver!!!

Is the coil bracket securely grounded? The coil / ignitor will not spark if not grounded. If you are 100% sure it's VERY grounded, it could be your coil or ignitor gone faulty. I suggest hitting the junk yard (or parts store) for spare parts before going to Nissan and blowing $500 on new parts before checking (not saying you would... but some people do).

 

Well so far the car has new plugs and wires, distributor cap and rotor, coil and power transmitter. Like I said there's continuity through the wires, and the ECU's green light comes on when switched. The connector to the transmitter is getting 12 volts, but no spark. I'm worried about the coil though because it was from Autozone and looks different (a little smaller), but I checked there and a couple other parts stores and they all indicated the same type replacement. I know the FSM lists the Turbo coil as different so I'm worried about the databases the parts stores pull from, whether it differentiates. But I don't want to throw more money at the problem by buying yet another coil from the dealer to make sure. Any other ideas to check as to why I have no spark? Everything tested good through the pins as far as sensors (except for AFM as I said before). Fusible links were just replaced also. Thanks for any ideas.

 

You didn't answer my question:

Having an n/a coil, or any under powered coil is not going to PREVENT spark. It would only reduce the power of the spark.

 

also the coil shouldnt spark, it should send electricity to the dizzy. if it's sparking, then you have a short....

 

You said there is continuity... but do you have power at the coil? Just put your voltmeter on the two power posts. You should have 12v with ignition, or is this your first issue?

 

With ignition on, if I put one lead on the positive post of the coil and the other on the frame I read 12.3v. If I put one on positive post and one on negative post of coil I read zero volts.

Of course when I say no spark at coil, I mean no spark off the coil wire.

btw I priced a coil from the dealer for the hell of it..."are you sitting down?!" the parts guy said...$456. Unbelievable.

 

sounds like the coil isn't grounded ...now that's a new idea!

 

Oh I hope so. The feeling of stupidity I'd have would be nothing compared to the frustration this has been. When you say ground the coil, do you mean the bracket being bolted to the body, or the blue wire coming off the negative terminal, or what? (yes I'm dumb, just humor me)

btw I have the blue wire going to negative and black/white going to positive. Is that correct?

Thanks for all your help. I know I must seem an idiot.

 

I do remember that black is positive. Sounds strange but its true.

oh, yours is a turbo too. I'll go take a pic.

blue goes right from neg on the coil to the little pack on the side as well to the blue wire from the coil wiring harness.
It does not look like the coil itself is grounded to the mounting bracket.

 

Okay, I tried to decipher what I'm looking at with the FSM tonight. The wiring diagram shows the blue and b/w wires between the power transmitter and the coil, but it also shows the power transmitter going to ground. Not seeing any other wires, I assumed it was grounding through the bracket to the body. So I took everything off and cleaned the hell out of it, bolted a new ground wire specifically from the coil bracket to the body, added a #1 cable from the battery to the body as a main ground (realized that was only grounding to starter/transmission before), and fixed the wire going to the distributor with the resistor on it (worn through in spots). Sanded all the ground spots down to bare metal and slathered dielectric grease as i bolted it all back together.

Result: No change, 12v from + side of coil to body, zero volts from + to - posts. No spark off coil wire when starting.

At this point I think it's safe to assume the coil bracket is grounded. Any idea where the 'other' blue wire from the negative side goes once it enters the wiring harness?

Anything else I could try (besides throwing a match)??

 

Try another ecu (if you have a spare). One of my turbo ecu's is faulty & doesn't spark.

Also (and before changing ecu's), check to make sure the LED light is lit in the inspection hole of the ECU (when the key is ON).

 

You should only see pulsed 12V across the coil when its cranking. Sound like the transistor isn't firing? Check and see if the signal from the ECU to the power transistor is there then check to see if the output from the transistor to the coil is there.

 

it's more than likely the igniter, to check the ECU check pulse to the first fuel injector or take the spark plug out to see if it is soaked in gas and if it is then the ECU is working and the igniter is bad or a ground is not connected properly.