_Donovan_ Posted June 13, 2014 Share Posted June 13, 2014 Hello everyone. I will make this quick. We were working on the car and replaced the battery. The leads were put on backwards (Neg on Pos) and was let to sit like that for a considerable amount of time. The battery was not that strong to begin with but I am wondering what may have been affected. The car is now cranking but not starting. Spark at the plugs, fuel pressure, and air flow but no start. Anyone do this before and realized what was affected? Thanks in advance. Quote Link to comment Share on other sites More sharing options...
hwvigo Posted June 13, 2014 Share Posted June 13, 2014 Need a little more info on '''' the car "" . Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 13, 2014 Share Posted June 13, 2014 If you hook up jumper cables backwards on a 240 you blow the fusible link between the pos terminal and the starter. Quote Link to comment Share on other sites More sharing options...
socorob Posted June 13, 2014 Share Posted June 13, 2014 Unless its an old British car, then backwards is actually forwards. Quote Link to comment Share on other sites More sharing options...
_Donovan_ Posted June 13, 2014 Author Share Posted June 13, 2014 WOW, rushing again at work. It is a 75 Datsun 280Z. Quote Link to comment Share on other sites More sharing options...
hwvigo Posted June 13, 2014 Share Posted June 13, 2014 Did you attempt to crank with it hooked up backwards? And just so I am understanding your post it is now turning over with good spark on all plugs and fuel. do you still have stock efi? Quote Link to comment Share on other sites More sharing options...
NewZed Posted June 13, 2014 Share Posted June 13, 2014 Best to just get a meter and make sure power is getting where it needs to go. The EFI system has its own fusible link, inline on the supply wire at the positive terminal. It's green. Quote Link to comment Share on other sites More sharing options...
Phantom Posted June 13, 2014 Share Posted June 13, 2014 Yeah - and half the time they blow and you can't even tell it. I hate fusible links! Still using the same battery? Check the voltage it's putting out. If it's 12 or lower it's basically shot and just not giving you enough juice to get the car going. NewZed is definitely about getting a meter and testing things. I'd start with that fusible link. Quote Link to comment Share on other sites More sharing options...
_Donovan_ Posted June 16, 2014 Author Share Posted June 16, 2014 Fusable Link was blown. Changed them all and will be ordering a MaxiFuse set up for this. But now suddenly everything went dead. Was cranking but now nothing. Acts as if there is no battery in the car. Getting the meter out tomorrow to see what is up now. Quote Link to comment Share on other sites More sharing options...
_Donovan_ Posted June 21, 2014 Author Share Posted June 21, 2014 would it be possible to burn out my shunt by doing this? I am trying to follow the wiring diagram and diagnose where I am losing current. Right now I am at the shunt as the cause. Quote Link to comment Share on other sites More sharing options...
NewZed Posted June 21, 2014 Share Posted June 21, 2014 Get a voltmeter and start probing. Eventually you'll find a spot that has no voltage when it should. Once you try it you'll never go back. Quote Link to comment Share on other sites More sharing options...
_Donovan_ Posted June 24, 2014 Author Share Posted June 24, 2014 It turned out to be the shunt. Quote Link to comment Share on other sites More sharing options...
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