No spark to plugs

[Just.Ice.T]

So, I have a '79 510 wagon. I purchased a donor '81 wagon, for the engine(z20)/tranny (5spd, dogleg)/etc. The donor ran before I did the swap. Now, after the motor and everything is swapped, the car is not getting spark to the plugs.

 

Troubleshooting so far: (keep in mind, I replaced these parts because the originals were.. well.. originals, and looked terrible anyways)

 

I have switched power (12+ V) all the way to the ICM on the dizzy. I replaced the dizzy cap, rotor, plug wires, plugs, ignition coil, Ignition module, and pickup coil (inside the dizzy). Basically every part of the ignition, except relays/switches/fuses which are all fine.

 

The weirdest part... I got the car running BEFORE I replaced the ign. coil, ign. module, and pickup coil...

 

After celebrating a bit, for a job well done, I started bundling wires together to clean up the engine bay. THAT'S when it decided not to start again. Thus, I went down the list, replacing the components that were not in the average tune-up (after hours of checking wiring diagrams/connections).

 

I'm assuming it's something simple that I'm overlooking. A missing ground perhaps? Finding any kind of wiring diagram that matches this car is a headache in itself. With that said, it's not really a complicated setup...

 

For the record, the motor ran smoothly when I got it running after the swap.

 

What do you think?

[]2eDeYe]

I think you have a wire that is not connected or has been broken during the swap. 

[datzenmike]

Only things that need replacing are the cap, rotor, plugs and the wires. These wear out or don't age well. You may have introduced a faulty part into the mix. Never fix what ain't broken.

 

'81 so this has 8 plug wires? and two coils? The '80 had only 4 plugs and the distributor is identical to the earlier L20B.

 

You should have 12v on both positive terminals on the coils.

The negative sides go to the module to be grounded. IIRC the power to the module is on the center terminal of the module and the coil negative wires on either side.

Make sure the distributor is snugly bolted down as it has to be grounded to the engine.

 

 

[Just.Ice.T]

Thanks for the replies!

 

i should’ve stated that the PO ran the car off of a 4 plug dizzy, one coil. With a little timing advance it ran smooth. I will check to see if it’s bolted down tightly today. I will also check the wiring again.

[datzenmike]

 

Ignore the coil. For true EI output use the Nissan 0.75-1.0 ohm coil designed to work without a ballast.

 

The distributor may have a ground lug on the side.

[Just.Ice.T]

Update: I made sure the dizzy was attached tightly. I added another ground wire to the body of the dizzy, going to the a ground point on the car body. I have continuity from battery + to the ground I put in, the dizzy itself, and the screws that attach the ICM to the dizzy. I also made sure that the dizzy was actually spinning.

 

So, now that whole thing seems grounded, I hooked up a 12v bulb to the negative terminal on the ignition coil. This is supposed to have a pulsing signal, I believe. But both that terminal, and the positive, both stay constant with no dip in signal. With that being said, perhaps the new ICM I put in is faulty? Is the lack of pulsing signal keeping the coil from firing? Or is the fact that I have 12v on the negative terminal of the coil evidence that it’s NOT being grounded by the ICM? 

 

I apologize for all the questions

[Crashtd420]

A coil will show 12v on the negative side till it recieves the negative trigger.. so Yes there should be a negative pulse happening...

One thing you can do is leave power to the coil.... disconnect the negative side and use a small piece of wire, touch the negative terminal of the coil to ground and release and see if it makes the sparkplug spark or not.....

If it does then the coil is good and you have something wrong at the distributor....

Either the icm is bad or the trigger from the distributor to the icm is bad.....

Edited August 6, 2019 by Crashtd420

[Just.Ice.T]

If it doesn’t, does would that imply that the coil is bad? 

 

I tried what you suggested, with both the old and new ICM installed, and still no spark.

 

i tried it with my old and new coil, as well.

[datzenmike]

Turn ignition on. You should have 12v at the + (positive) terminal of the coil. Like mentioned above get a short length of wire and ground one end and briefly touch the - (negative) terminal on the coil. When you release the ground the coil will spark.

 

Put an old spark plug in the coil wire that goes to the distributor cap. Lay the spark plug on a grounded surface to see the spark. You can't use any of the spark plug wires because the rotor could be pointing anywhere.

 

The chance of having two bad coils is astronomical.  I bet both coils are good.

 

Make sure the 12v goes to the B terminal. C to the coil negative.

 

There are also two wires from the rotor going to the module. Green wire to G and Red wire to R. They may be reversed.

[Just.Ice.T]

I have 12v to the coil. I did the test you mentioned (touching a grounded wire to the negative terminal while my wife cranked the car). I tried it with both (new and old) coils, and both ICMs. Still nothing.  I’ll try it with a spark plug in the center coil wire tomorrow. 

 

For the pickup coil wires plugging into the ICM, There’s no G or R on the unit, but one wire is longer than the other, and the colors matched the one I took out. So I hooked it back up the same way.

 

I didn’t know what year the dizzy was, but since it had EI and was a 4 plug, I bought ‘79 pickup coil and ICM for it. I didn’t think there would be differences between ‘79 and ‘80 (if it is an ‘80). Would that make a difference? Should I have bought an ‘80 ICM and pickup coil?

 

 

EDIT: does the reluctor and stator points being misaligned have anything to do with it not firing?  Is there a way to adjust the stator?

 

Thanks, btw, for all of the quick replies. I'd really like to get this car back on the road. 

 

 

[Just.Ice.T]

https://www.dropbox.com/s/ioflt3blwg846xl/Photo Aug 07%2C 07 20 56.jpg?dl=0

 

I can’t turn it enough for these to line up

[datzenmike]

When holding the ground wire to the coil you do not need to turn the engine with the starter. Just the ignition ON.

 

The module should have the terminals marked on it, just like the top two C & B.

 

 

One last thing.... check that there is 12v when the starter is being used.

 

 

This was running, it will run again.

[Just.Ice.T]

Alright, 

 

I hooked the battery up to my other car with jumper cables (my battery started loosing juice)

 

at the coil +, it read just over 13V. Under crank, it dropped to 11.6V. I put a spark plug in the center cable, grounded it, and then touched a ground wire to the negative terminal of the coil. It did spark! It wasn’t strong, and it didn’t seem like it happened every time I touched the wire. 

 

Also, the new pickup coil and ICM I put in are for a ‘79. I didn't know what year distributor the PO put in, and I didn’t think there’d be much difference between the ‘79 and ‘80. But the OEM pickup coil part numbers do not match up with the replacement coil I put in, according to RockAuto.

 

Idk if that means anything... considering it’s color coded (and pretty much built) the same.

 

 

 

[datzenmike]

The stator and reluctor line up as the engine turns. Hopefully at or just before Top Dead Center on the plug that needs to fire. Turn the engine with the starter to get close then turn the front pulley by hand using the fan belt or a wrench to line them up. It looks ok from here.

 

 

11 v sounds about right when using the starter.

 

Make sure the module back side is clean and electrically grounded to the distributor case with the mounting screws.

 

If nothing try the other coil... of nothing try the other module.

 

Can't say this enough don't fix what isn't broken... this was a runner.

 

 

[Just.Ice.T]

I have continuity to both screws holding the module on. Checking for continuity from the C connection on the module, the signal doesn’t pulse with either module I have. 

 

I’ll try to return this module in exchange for another, and get back here with the results... 

 

Thank you for all of the suggestions!

 

It sucks that they didn’t work. I did get this car running after the swap, but the day after that it wouldn’t start again, which is why I went down this rabbit hole.

 

but again, thank you for the help. I’ll letcha know what happens!

[Just.Ice.T]

Looking at the module that came with the car, it says E12-80 on the side. 

 

Are replacements really in the in the hundreds of dollars?

 

the one I bought to replace it was $20

[Crashtd420]

Before you return it or replace it  and spend more money you should make sure the distributor is sending a signal to the icm.....

 

Can you check the green and red wires coming off the distributor?

 

Sounds like whatever is suppose to trigger the module isnt.....

Hopefully datsunmike can clarify that....

[Just.Ice.T]

UPDATE:

     Due to the fact that I'm on a time crunch now, I ordered a new dizzy. I got the Hot-spark replacement that fits an L20. Install was straight forward, thanks to there only being one way it can go in. I got it installed, along with the 3.0 ohm coil, and WA-LA! spark! I had to reuse the original mounting bracket, the new one's dimensions aren't correct.

 

It fired up a couple of times, but it mostly just coughs and spits out of the carb. I have the Weber 32/36 installed on it. I feel like it'll be a balance of fuel/air and timing adjustments now. The timing has to be pretty latent/early, it shot flame out of the carb one time that it backfired. I'm assuming this is due to the spark happening before the valve shuts completely.

 

Anyways, I'm making progress. I plan on sending the original dizzy out to be rebuilt when I have the funds. I'm not completely sold on this hot-spark unit yet, but it seems to be doing the job. At the very least, if the new one holds up, I can sell the old one... they seem to be pretty rare to find rebuilt.

 

 

[datzenmike]

Try starting with the choke on. Lean mixtures when engine is cold will cause a backfire through the carb.

[banzai510(hainz)]

HOT SPARK the hole where it mounts down to might not be in the correct spot, its a Generic distributor for all year L motors. And they had different timming set  ups.

Put moto on TDC and see where the rotor points at . Hopefully right on a plug wire. If not you turn the dist till it come really close hopefully within the range of the timming slot. If too much it goes bad as your getting to spark to the next wire which is out of phase.

Most people cut the timming plate or move the distributor spindal in the direction it goes to(not loose oil in pump as needed to help suck up oil)

 

 

ezest way to find TDC is open oil cap. that lobe you see get it near the 9 o clock position then dial it up to Zero on crank going clock wise then iopen dist cap and see where it is. If close just turn the dist till it starts( w/o the bolt holding and limiting it movement of adv/retard.

Edited August 15, 2019 by banzai510(hainz)

[Just.Ice.T]

I got it running! I rotated the spark plug wires clockwise to give it more advance, and wa-la, it started. It runs now, but it still sounds like the timing is just a little latent. The dizzy is turned with as much advance that the slot allows. I’ll try rotating the plug wires clockwise once more, then rotate the dizzy all the way latent and see what happens. It’s really close though. 

 

The PO already ground out a little bit of the slot for the dizzy to rotate counterclockwise more (more latent). So I’m guessing that’s how they had it set up.

 

I’ll also pick up a timing light to make sure

 

again, thank you for all the replies, and help throughout this process!

[banzai510(hainz)]

Like I said put it on TDC then you can see how far you off by looking at the rotor position. Moveing plug wires is a 90 deg move and the slots get i in closer but the timming slot range is usually only 25 degs.  When you get the dizyz to go from 0-25 deg then your on.  Yes timming light will catch this sooner and tell how far you off

[Just.Ice.T]

I got a test light, and discovered that the timing was pretty advanced, if I’m reading the time gauge on the motor properly. Under the hood, it looks like the sticker shows about 7ish degrees. Without doing anything, car running, the time slot on the crank pulley wasn’t even close to being near the gauge. 

 

I adjusted the dizzy back within the normal parameters of the slots on the dizzy’s plate. I got it to about 12-15 degrees on the motor’s gauge. The motor liked being a little bit advanced from the sticker, probably from running 4 plugs instead of 8. This was kind of humbling... I got so far into tinkering with it, I threw it more off than what it needed.

 

anywho, she runs pretty smooth now. I have to fiddle with the air/fuel a little bit. It smells like it’s running rich, but when I lean it out the motor doesn’t like it. 

 

 

 

Thank you for all of the suggestions/help!

[datzenmike]

12 sounds about right. The 2 liter single plug L20B is set there. The Z20 is almost identical below the head as the L20B.

 

All engines like more advance at idle so don't go running what it likes here because total mechanical advance is set to add about 20 -22 more degrees and too much total advance above around 32? is bad for an engine. Listen for pinging under load and back the timing a degree at a time till mostly gone.

[G8KeaPoR]

I skipped just about the whole thread so feel free to slap me. I had the same problem on my 71 which led me to rewriting either everything new rather than troubleshoot this 500 time. Use an ohm meter between the coil wires or the igniter wires on the plugs on both ends of the wires. If those pass then do the same on the other end of the connector that goes to the actual source/switch. (Yes the explanation is truncated.   Another thing I do is wiggle the wire I am testing. Anything more that a 5ohm resistance change says you have a wire that is either shorting out or given the year and lack of fire the wire has broken internally and again I skipped everything between my reply and your initial post but the first wire I would check is the trigger that goes to the coil since usually a power wire just catches fire when it shorts be it internally or externally. Hope you got it fixed.