xxPL510xx Posted November 13, 2014 Report Share Posted November 13, 2014 1972 Datsun 510 wagon L18 Weber downdraft Electronic ignition (Dizzy unknown donor) 620 Ignition coil (New from autozone ~ 3 months ago) I was on my way to work last week in the wagon and all of a sudden the car stopped. Luckily I was at the top of a hill so it was all downhill until I could find a spot to park B) . Upon inspection I found no spark from the ignition (ign) coil. I checked the voltage across the ign coil which is 0 Volts. I suspect the common ground wire connected to the dizzy (through the matchbox) is what is at fault, it has a bad splice. I plan on properly soldering it this weekend to rule out an open connection. Is it possible the matchbox can go bad? If what kind of test can I do? Thanks guys! Quote Link to comment
banzai510(hainz) Posted November 13, 2014 Report Share Posted November 13, 2014 olddatsuns.com the tech section you look at the fuse 1st? You ck for voltage the the blk/wht wire with key ON? 12 volts. most times the coil never goes bad give us more info and maybe photos. Quote Link to comment
datzenmike Posted November 13, 2014 Report Share Posted November 13, 2014 Even if the ground were at fault you would still have 12 volts at the positive terminal of the coil and to the EI dizzy. The dizzy simply turns the ground through the coil on and off to generate a spark. There's no fuse in the ignition circuit other than the fusible link and if that blew you would have nothing working at the ignition switch. Does the starter work when the key is turned? If so, all you need is a jumper wire from the battery positive to the coil positive to get you going if you need to get home. Engine will not shut off, once started, with this set up.... you will have to remove the wire to do that... This is a temporary solution just to get you home!!!!! 1 Quote Link to comment
dr.feltersnatch Posted November 13, 2014 Report Share Posted November 13, 2014 Matchboxes rarely go bad. Grab a new wire and connect it from matchbox to ground. If it fires up you know the fault is in the wiring somewhere. You can do the same test with positive like mike said. Go from battery + to coil + if it fires then you know you have a problem in that circuit. Dont test from coil+ to coil- test from coil+ to a known good ground. Key on it should have power. Like mike said the matchbox controls the ground circuit. Quote Link to comment
banzai510(hainz) Posted November 13, 2014 Report Share Posted November 13, 2014 There's no fuse in the ignition circuit ???? You sure Mike. ? I think there is a Ignition fuse Quote Link to comment
xxPL510xx Posted November 15, 2014 Author Report Share Posted November 15, 2014 olddatsuns.com the tech section you look at the fuse 1st? You ck for voltage the the blk/wht wire with key ON? 12 volts. most times the coil never goes bad give us more info and maybe photos. Yeah there is 12 Volts on the + terminal of the ign coil. I'll try to post pictures tomorrow when I do the soldering joint. Even if the ground were at fault you would still have 12 volts at the positive terminal of the coil and to the EI dizzy. The dizzy simply turns the ground through the coil on and off to generate a spark. There's no fuse in the ignition circuit other than the fusible link and if that blew you would have nothing working at the ignition switch. Does the starter work when the key is turned? If so, all you need is a jumper wire from the battery positive to the coil positive to get you going if you need to get home. Engine will not shut off, once started, with this set up.... you will have to remove the wire to do that... This is a temporary solution just to get you home!!!!! I forgot to mention that I did check the + terminal of the ign coil, it does read 12 V. The - terminal of the coil does not show 12 V (battery + to coil -). That's why I think it's the ground connection. The starter does work, motor turns over. I should carry spare jumper wires for that temporary solution for emergencies :thumbup: I'll post pictures tomorrow. Any one ever open up a matchbox? The reason being is I would like to replace the whole wire(s) instead of splicing. I really don't like splices.. Thanks again guys!. Quote Link to comment
datzenmike Posted November 15, 2014 Report Share Posted November 15, 2014 There's no fuse in the ignition circuit ???? You sure Mike. ? I think there is a Ignition fuse Yeah, I looked and the ignition switch is directly wired to the single fusible link at the starter. Some power is sent to the fuse box to switch stuff like the heater and wipers off, but the ignition ON and the START signal both go to the coil and the ballast. Maybe later 510s had a fuse? My wiring diagrams are from the Haynes #123 manual. Quote Link to comment
banzai510(hainz) Posted November 15, 2014 Report Share Posted November 15, 2014 I forgot to mention that I did check the + terminal of the ign coil, it does read 12 V. The - terminal of the coil does not show 12 V (battery + to coil -). That's why I think it's the ground connection. the - side of the coil should have 12volts also using a volt meter and grounding the voltmeter to the chassis. The coil will not have 12volt on the minus side of the coil if the points are shorted if this is a point contact distributor. I worked on a 67 520 and had this same proplem , when I tool the dizzy cap off the coil would fire. then when I put it cack on the coil then stopped fireing. what I did is fuck around inside the dizzy and it seem to be grounding out since you have a elelctronic dizzy I don't know much about them either they work or don't Quote Link to comment
datzenmike Posted November 15, 2014 Report Share Posted November 15, 2014 I forgot to mention that I did check the + terminal of the ign coil, it does read 12 V. The - terminal of the coil does not show 12 V (battery + to coil -). That's why I think it's the ground connection. Take the wires off the - side of the coil and check for voltage with the key on. You may have 6 volts or something but this will show that the primary wiring isn't broken inside. To prove this, briefly ground the - coil terminal and the coil should spark. If YES connect the wires back up... the coil is good. Any one ever open up a matchbox? The reason being is I would like to replace the whole wire(s) instead of splicing. I really don't like splices.. This is an interesting statement. And likely what your problem is. Inspect your splices something came undone. Be sure that the distributor is well grounded!!! There is nothing inside a matchbox to splice. There are two terminals on the outside top. One that the +12 volts goes to and the other turns the - side of the coil off and on to ground. On the back side of the matchbox are two terminals for the Red and the Green magnetic sense wires from the stator. Yes, I took one apart once. Don't recommend wasting a good one on that there's nothing to see... Just for the hell of it I also took a late 280zx or Maxima EFI matchbox apart It has a built in ignition retard system goverened by the EFI ECU... Quote Link to comment
alexjalos Posted August 12, 2018 Report Share Posted August 12, 2018 im planning to do this as well to hot wire the ignition coil. i have the same problem with the ignition , my car does not have any type of spark and there is no 12 v at the terminal so the ignition coil does not gets any power , i dont knoe if this has a fuse in between the ignition or there is something else going on , when i open the switch there is no lights either in the dash or in the headlights or taillights . thanks a lot for the help . Quote Link to comment
datzenmike Posted August 12, 2018 Report Share Posted August 12, 2018 I'm assuming the battery is charged and the terminals on it clean and tight? and the ground from the battery is tightly bolted to the block somewhere and there is a solid ground to the body sheet metal? (often at the voltage regulator mounting bolt) and the positive cable tightly bolted to the starter? The positive cable should have fusible links providing power to the the ignition switch and one side of the fuse box. The ignition turns certain functions off like the heater, radio and wipers. Other electrical things like brake lights, horn and interior lights are on a separate circuit and fusible link. The ignition switch should power the coil, so if no power check that there is power to the ignition switch first by checking the fusible link connecting it to the battery. If no headlights it could be again, another fusible link or a fuse in the fuse box Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.