Guest 4.3L 280z Posted February 1, 2004 Share Posted February 1, 2004 First of all it is a 75 280z and has a 4bbl carb instead of fuel injection. The ignition was completely stock and we had the car running pretty good until I got a crane cams ps20 coil and switched coils and took off the original ballast resistor. It's missing really bad in the first three cylinders(I can take off first 3 plugs and can't here a difference) Car smokes black, and the coil is putting out a weak spark(orange in color). It does not change with the ballast resistor or without the ballast resistor that came with the coil. I can't try the original ballast resistor because I think it got a loose connection after I removed it to install the new coil(I guess because of age of wires) I tried the original coil w/out ballast resistor and a 12v coil I got from a friend and he says its good. There is no difference between coils but The problem is getting worse everytime I start the car. The plugs are all dry and very dark black also. There is 12volts going to the ballast resistor. Also the wire that was connected in the middle of the original resistor only has 12volts when turning over right? It only has nine. And the other wire on the output of resistor that goes to coil was the condensor right? I've tried connecting it and disconnecting it. Me or my dad have know idea of what else to do. We've been working on this all day!!!!!! Quote Link to comment Share on other sites More sharing options...
fastzcars Posted February 1, 2004 Share Posted February 1, 2004 I would check the plug wire from the coil to the distributer cap. May be it was damaged when it was pulled off the old coil? I find that if I get stuck on a problem, I just stop, walk away, and sleep on it. Then I start over and assume nothing. Meaning I would check the whole spark system. Good luck. Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted February 1, 2004 Share Posted February 1, 2004 You didn't say what happened when you take the plug wires off the back 3 cylinders... If only indivilual cylinders are affected then you have a plug wire problem, or a problem in your distributor cap, period. Thisis safe to say, because the coil is supplying ALL the cylinders the same, the only possible differences that would account for some cylinders not getting spark is something wrong in the dist cap or the wires. Have you put the spark plug wires to ground to see if there is spark from each of the wires? Have you checked the wires resistance with a V/O meter? You want to make sure all the electrical connections to the coil are good and tight, with clean wires. I am assuming the ring connectors are still on the ends of the wires - right? Quote Link to comment Share on other sites More sharing options...
Guest 4.3L 280z Posted February 1, 2004 Share Posted February 1, 2004 actually there all getting a spark just weak. The plug from coil to distributor was changed and made no difference. I will check the other plug wires but i don't think thats it because they were fine before. Right now I'm changing the transistor module to the corvette HEI type. I found this mod on a internet sight. I don't know which wire is pos and neg on the distributor though. There are 3 going to the distributor. I need to get it on the road tomorrow because I can't drive my parents truck to much longer and I told my mom that it would be done THIS WEEKEND. Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted February 1, 2004 Share Posted February 1, 2004 It's easy to make assumptions when you are not given full info. Your original post aid you couldn't "here" a difference on the first 3 cylinders when you disconnected the spark plug wire from them, so I assummed you were saying the other three DID have a difference. You appear to have a wiring problem - your inability to be able to put the original system back in would indicate that, which is why I mentioned connectors before. Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted February 1, 2004 Share Posted February 1, 2004 hmm... interesting... if all you did was switch coils like you claim... then nothing will change. I suspect... you put on a new coil, tried switching the ignition unit and pulled the plugs... In doing so you could have easily, switched spark plug wires, ie put the wrong wire from the dist to the plug, turned the dist to bump the timing off. Or messed up the wiring to start the car from the transistor ignition unit. The coil is NOT your problem judging by the voltage you claim as 9volts (assuming a fully charged battery here) then i'm willing to bet money you wired the new ignition unit wrong. I speak from previous expierience wiring my 280. I'd recomend double checking your wiring. but it's not your coil, i've used good and bad coils you can't tell the difference between them at idle, only till you heat everything up and the coil starts to misfire and act up. hope this helps -Ed Quote Link to comment Share on other sites More sharing options...
A. G. Olphart Posted February 5, 2004 Share Posted February 5, 2004 Are you absolutely cetain that this is an ignition problem??? (Maybe Harry Coincidence has visited your garage). Lots of black smoke genereally indicates excess gasoline (stuck choke or other carb malfunction). Does your 4BBL manifold have a divider, so the front 3 cylinders are fed from one half of the carb & the back 3 from the other? If so, that could explain why 3 work & 3 don't. If you have 3 strong sparks & 3 weak sparks... Is this a points distributor? If yes, check point condition & gap-- (Sorry, I've never actually run a Z, just collecting parts for a hybrid). Luck--- Quote Link to comment Share on other sites More sharing options...
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