reintr0ducing Posted May 17, 2009 Share Posted May 17, 2009 so we were driving around in my z (73 240z, L28 swapped with roundtop SU's) and the battery area sparks up and the car dies. upon lifting the hood, the inspection panel got fried (paint was burned, hinge broke), and the ground wire coming off the battery cable was burned (plastic burned and wire broken). researching online, it seems as though i need to clean my grounds and make sure i have good contact. also, people were talking about needing to rebuild the starter (?). is this the right direction for me to take? what would cause this issue? i was driving around for a good 30 minutes with no problems before this happened. Quote Link to comment Share on other sites More sharing options...
Oddjob Posted May 17, 2009 Share Posted May 17, 2009 Humm... From your description, it sounds like a high amp short... sort of like arc welding. Your alternator (assuming stock) does not produce enough current to do that kind of damage, so the current source had to be the battery. Look for some path where the positive battery terminal or cable came into contact with a ground. The older Zs are known for bad grounds, but this doesn't sound like it was caused by that. The starter wouldn't have much to do with it either, except that your positive battery cable goes directly there from the battery. Quote Link to comment Share on other sites More sharing options...
chrism Posted May 17, 2009 Share Posted May 17, 2009 A loose ground cable will cause arcing at the terminal lug connection on the battery. It also creates resistance. Any time you have resistance in a circuit, you have power dissipation and heat is the byproduct of power dissipation. That will cause the cable to heat up. If the cable has been this way for some time, you will want to inspect the lug and terminal. It probably has pitting on the inside where the lug and the terminal make contact. If that is the case, I would recommend getting a new cable terminal. Make sure it is on tight. Sometimes you can see smoke coming from the terminal connection when the car is starting. That is another sign that the terminal is not tight enough. Quote Link to comment Share on other sites More sharing options...
Oddjob Posted May 18, 2009 Share Posted May 18, 2009 A loose ground cable will cause arcing at the terminal lug connection on the battery.It also creates resistance. Any time you have resistance in a circuit, you have power dissipation and heat is the byproduct of power dissipation. That will cause the cable to heat up. This is all absolutely correct, and is a possible problem. However, I don't think it is the cause of your problem. Here's why: Your problem occured suddenly, and killed the car. You don't say whether it was day or night, but I assumed it was daytime. If so, the amp draw on your electrical system was minimal (no lights on, and you weren't starting the car). You say the ground cable was melted and broken. I took "broken" to mean burned through. It takes much more amperage to do that than a loose terminal would generate. And lastly, you say the paint was burned. If that happened suddenly, then again, you generated more heat than a loose terminal. My money is on a short. Quote Link to comment Share on other sites More sharing options...
twofouroh Posted May 22, 2009 Share Posted May 22, 2009 Which way is your battery turned? If the POS is away from the engine, that's wrong, AFAIK. If your pos term touched the body, it would have done everything you said happened. Fix would be to turn it around and buy the stuff to secure the batt. Black Dragon has it all, even the top plate. Or you could just use their catalog to source junkyard parts and fab a top plate Quote Link to comment Share on other sites More sharing options...
reintr0ducing Posted May 30, 2009 Author Share Posted May 30, 2009 This is all absolutely correct, and is a possible problem. However, I don't think it is the cause of your problem. Here's why: Your problem occured suddenly, and killed the car. You don't say whether it was day or night, but I assumed it was daytime. If so, the amp draw on your electrical system was minimal (no lights on, and you weren't starting the car). You say the ground cable was melted and broken. I took "broken" to mean burned through. It takes much more amperage to do that than a loose terminal would generate. And lastly, you say the paint was burned. If that happened suddenly, then again, you generated more heat than a loose terminal. My money is on a short. sorry for being so vague.. it was at night time and we were driving around for a good 20 minutes or so. Which way is your battery turned? If the POS is away from the engine, that's wrong, AFAIK. If your pos term touched the body, it would have done everything you said happened. Fix would be to turn it around and buy the stuff to secure the batt. Black Dragon has it all, even the top plate. Or you could just use their catalog to source junkyard parts and fab a top plate my pos terminal is facing away from the engine. after i looked at the inspection panel, it looks like the terminal may have touched the metal. i've gotta double check though. Quote Link to comment Share on other sites More sharing options...
srgunz Posted May 31, 2009 Share Posted May 31, 2009 after i looked at the inspection panel, it looks like the terminal may have touched the metal. i've gotta double check though. That is exactly what happenes to the Z car if the battery is not tied down tight. You are by far not the first one this has happened to. Poor design by the factory. One fix is you can buy the exact same battery with the + and - opposite of what you have. This puts the negative side beneath the inspection lid instead of the pos. The low budget way is to just tape up the pos. terminal real good and you will not have any more shorting. Quote Link to comment Share on other sites More sharing options...
zedsn Posted June 3, 2009 Share Posted June 3, 2009 put on a new negative cable and go from there. Also make sure your battery is up to par and still has over 12 volts. 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.