I have this posted also in my build thread but I think this would be a better place for this. I have been problems getting my car to start for the past couple of months. First i thought it was the connections to the battery, tightened and replaced all needed connections. Still started only sometimes, so then I figured maybe the battery, replaced that with a brand new Odyssey PC680, and still the same problem. So then I looked into the battery ground which was poorly connected with a cheap wire ( the battery is relocated to the back) so I replaced the battery ground with a brand new 2ga battery cable, still won't start.

It sometimes starts when the car is jumped, when the car was running I took the positive cable off the battery and the car continued to run so the alternator should be good. The battery will not keep a charge what so ever, when it is not jumped it reads right around 3v.

All I can think of now is that there is a short somewhere in the wiring, either the power cable back to the battery, which is what I will replace next. Other than that possibly a short or drain somewhere in the tucked harness.

I just don't understand why sometimes it has started and been fine, for more than a week one time and then after that I come out and nothing completely dead, no lights, no turning over nothing.

The last time I drove it a couple of weeks ago I drove it around for about an hour came back parked it, shut it off, went to start it a minute later and the lights dimly came on.

Does anyone have any advice for me I am so frustrated and confused at this point, I can't afford to just keep replacing things if it is not the problem!

 

elaborate.
what does it do/not do when jumped and still fails to start?

you need to check:
charging voltage
voltage drop
parasitic drain


you likely don't have a shorted wire. that would blow a fuse or start a fire.

you likely still have bad connections, especially considering that the battery has been relocated.

check and clean the main connections at the alternator and starter. Also, the ground from the transmission to the frame is a common suspect.

alternators can go bad and actually drain voltage from the battery when the car is shut off as well.

 

When it is jumped and doesn't start the lights will dimly come on and will slowly crank, just seems like it dosen't have enough power to start.

The only thing I haven't checked is the connections on the starter. The power cable goes from the starter to the fuse box and then to the battery, is this correct?

I did test the alternator and it was good when I tested it, is it possible that it could sometimes work and sometimes not before it completely fails?

 

Alternator has NOTHING to do with the vehicle starting. If you are getting 3v from the battery while the connections are hooked up, most likely a wire is crossed/shorted. You would be suprised - just because a wire is shorted doesn't mean a fuse will blow or a fire will start. As far as helping... there is too much change from factory to know what went wrong where; the only advice is grab some help and a multimeter and go to town - Have Fun!