Scottie-GNZ Posted July 9, 2007 Share Posted July 9, 2007 Bear with me here folks, but I need some help with 280Z/ZX distributors. I am trying to help my buddy get his engine fired up. It is an L28 with triples and an early electronic distributor. I have not messed with an OEM distributor since 1942 and the engine is in a kit car so it does not have the OEM wiring harness. The engine makes no attempt to fire. I have spark going into the cap but none at the plugs. To me, the wiring looks suspect but he claims the guy who did the installation drove the car and the engine was fired up every so often while it was being stored for several years. The coil pos & neg goes into a harness that goes inside the car. I have no clue where it goes nor much desire to trace it down. The distibutor has 2 wires, red and green, coming out of it and are connected to a red and green wire coming out of the harness coming from inside the car. I assume red is 12V and green is tach signal. The distributor has a male terminal blade on the vacuum cannister (yellow circle) but nothing is connected to it and seems like nothing has ever been connected to it. I have no idea if it is wired correctly and have to take someone's word that the engine ran but now it makes no attempt to fire. I tried jumping the coil's neg terminal to the blade and connecting the blade to ground and it made no difference. I got another ditributor from Z-Gad but it is a later model with an ignition module on the side of it and 2 blades on top of the ign module labeled "C" & "B". There are 2 wires, red & green, inside the distributor that go into the ign module and I assume 12V and tach signal. My plan is to swap distributors to see if the original is bad, but I have my doubts about the wiring as it is. Any thoughts would be appreciated. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 9, 2007 Share Posted July 9, 2007 These distributors are extremely simple. That's the good news. The bad news is that the vacuum advance mechanisms are pretty much always broken. Even if it is disconnected it can still cause problems, because the ball bearings in the advance mechanism hold everything in line, and in my case when the bearings came out the stator tilted inside the housing, and the trigger wheel hit the stator. Not good. Here is a website that tells you how to go through the whole thing, including wiring: http://www.jrdemers.com/280ZX/distributor/distributor.html I used that page to rebuild mine and when I got to the vacuum advance I just took out all the unnecessary parts and JB welded the sucker solid so that it couldn't move at all. The mechanical is on the shaft, so I still have that working, but the vacuum is the breaker plate stuff that breaks all the time. The modules do go bad. Not frequently, but it does happen. If you want you don't have to replace the Nissan module, which is expensive. You can use a GM HEI module, or if you're good with wiring any number of other modules (a friend of mine uses Chrysler modules). Quote Link to comment Share on other sites More sharing options...
speeder Posted July 9, 2007 Share Posted July 9, 2007 I have spark going into the cap but none at the plugs. If you can pull the wire out of the cap, crank the engine, and see sparks from the coil wire to ground, but with the wire plugged in to the distributor see no spark at the plugs, then the distributor cap is bad. Probably the carbon button under the center coil connection is nfg. Either that or the rotor is somehow not turning. If the dizzy is the earlier VR type with no module on the side, then it needs an ignition amplifier such as the 280Z stocker or an MSD to run. Those red and green wires out of the dizzy go to the spark box, wherever that is. That male teminal is a ground that was connected to a noise suppression capacitor in a stock 280Z. Not significant. The coil positive terminal should have 12v on it when the ignition is on, and the negative terminal should have a negative pulse coming from the ( hidden) spark box. If your coil is sparking I would suspect that all the distributor and coil low voltage wiring is good as is the spark box. If the advance mechanism is bad, the car will still run, but badly. This assumes that any damage inside the dizzy isn't so bad that the reluctor wheel is looose/ cocked crooked and hitting stuff inside. That kind of badness should be evident with a quick visual inspection. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 10, 2007 Share Posted July 10, 2007 speeder is probably right, it's probably a missing or nfg button inside the cap that would cause spark at the coil but none at the plug wires. That or the brass part of the top of the rotor is busted off or something. Should be right in that area. I got a little confused yesterday as I thought the last picture was the distributor in the car. That is the ZX distributor. I think you might have the early one in the vehicle now though, is that right??? If that is so, and you wanted to try the ZX dizzy, it's REALLY easy. That black part with the green paint on it in the last pic is the module. I was too lazy to look it up yesterday, but B goes to + and C goes to - on the coil. You will want to jump the ballast resistor for max spark power. That's pretty much all there is to it for wiring as far as making it spark. I'm not entirely sure but I don't think that the old FI system has anything to do with the spark at all, so I think you can swap this out easily and with no other side effects. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted July 10, 2007 Author Share Posted July 10, 2007 Thanks for the responses guys. Been a little busy to get back on it. It is frigging roasting here and I am trying to get ready to test my car tomorrow night. JM, you are correct. the top pic is what is currently in the car and the bottom pic with the ign module is what I am considering swapping in if it is not something simple as the cap as Rick suggested. Quote Link to comment Share on other sites More sharing options...
340ZXTTAZ Posted July 10, 2007 Share Posted July 10, 2007 I agree with the above statements it probably in the cap or rotor. Plus make sure it's the right cap the later ign. module distributor has a taller cap i think? Any way check those things out and make sure all the connections are good especially the grounds. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted July 14, 2007 Author Share Posted July 14, 2007 Finally got around to messing with this again. It was easy enough to swap the dizzy to the ZX model and I connected the coil + to terminal B and coil - to terminal C. NADA! Same results. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 14, 2007 Share Posted July 14, 2007 That don't make no sense... If you have spark into the cap, then the problem would have to be between the coil wire's connection to the cap and the rotor, otherwise you would have spark to the plug wires. You've checked for spark at the cap going to the plug wires? If there's no spark there then again the problem has to be inside the cap, either the button or the rotor or some really bad carbon tracking inside the cap. You sure it's not something else like a set of bad plugs or some really bad old spark plug wires? Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted July 14, 2007 Author Share Posted July 14, 2007 With the 280Z dizzy, I had spark going into the cap. I see that the coil + & -wires go inside the car to an MSD box then out to the dizzy. I swapped in the 280ZX dizzy and connected the coil + to B and coil - to C and now I get no spark at the cap. I also get no voltage on the coil wire going to the dizzy B. I disconnected the coil from the MSD and just to test, went directly from the battery to the coil and saw 9.5V when cranking at the dizzy B but no spark going into the cap. Possible bad coil? Hate to just be swapping in new parts without knowing root cause. Plugs and wires are new, ZX dizzy came off Z-Gad's old L28ET. Quote Link to comment Share on other sites More sharing options...
speeder Posted July 16, 2007 Share Posted July 16, 2007 OK- In the first case (280Z Dizzy) you had an MSD being triggered via its VR inputs, triggering the coil, which produced a spark which was not making it through the distributor. In the second case(280ZX Dizzy) I think you are trying to trigger the coil directly from the distributor's integrated module, thus eliminating the MSD, and having no spark anywhere. Looks as if you're going bassackwards. My ZX shop manuals are at the shop, where I haven't been for 2 days. I'll look up the proper wiring for the ZX dizzy/module/coil tomorrow. If it was me I think I would go back to config. A and replace the cap and rotor. Quote Link to comment Share on other sites More sharing options...
340ZXTTAZ Posted July 17, 2007 Share Posted July 17, 2007 Scottie with the 280z dist. it was just closing a circuit to fire the MSD. That was working to the the distributor cap right? Now you said that with the ZX dist. you wired the "B" on the dist. to the Coil + and then you supplied 12VDC power to the same side of the coil. Then GRN or C on the dist. goes to the coil -. If the module is good it should ground the coil and thus firing it. You can check and groud the coil maunally and see if it fires. In any case it seems like problem still lies in either the cap, rotor, or both. Quote Link to comment Share on other sites More sharing options...
speeder Posted July 17, 2007 Share Posted July 17, 2007 Note the drawing at the bottom which is how you hook up the Diz . I think that single blade connection on the distributor is a ground point for the ignition module. In any case, make sure the distributor (with module) is well grounded. Pretty simple hookup. Quote Link to comment Share on other sites More sharing options...
steveosupremeo Posted August 1, 2007 Share Posted August 1, 2007 not to be a bummer, but most ignition systems don't operate at less than 9.6V and you are right below that. might try putting a strong battery in there and see if it brings the voltage up. if not i would definitely check battery cables, etc. maybe even go so far as to remove the ballast and see if the extra voltage will fire it off, i run my zx dizzy in my 77 without it. Quote Link to comment Share on other sites More sharing options...
speeder Posted August 1, 2007 Share Posted August 1, 2007 Just to update - After going back to the original config, we found that the rotor was not making good contact with the cap's center tower. As soon as that was fixed, we got a big fat purple MSD spark at the plugs. Quote Link to comment Share on other sites More sharing options...
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.