Rep Power: 0

For our 2005 civic SE we just swapped out the original engine (cracked header @ 135,000 mi) for one with 47,000 mi. It ran for 3 weeks or so, about 1000 mi then the instrument lights flickered and the following morning the car wouldn't start, the automatic locks didn't work either.

I jumped the car but when it was disconnected it died within a minute or so... Had the battery checked, it tested fine. Tightened the leads and it started ran for 5 minutes and restarted, but then an hour or so later back to the beginning with no nothing, well the instrument panel lighst work...

I checked the battery and ignition fuses and they are fine... disconnected and reconnected battery with no avail....

Any ideas before I tow it?

 
Rep Power: 512

If it was an immobilizer issue, the only thing that wouldn't work would be actually starting the car.

Have you had your alternator checked?

 
Rep Power: 233

sounds like an alternator problem to me. If it were an immobilizer issue, your starter would just crank and ur engine would not start, and your immobilizer (green Key) light would flash on your dash. try disconnecting ur positive battery cable while the engine is running. if it shuts off its your alternator

 
Rep Power: 812

are you sure the battery clamps are tight? sometimes you might think they are, but you can still turn them.

 
Rep Power: 214

Its not the immobilizer, like the others say it could be your alternator. Check to see if its working. Another could be the battery cables, see if they are really tight on there. And another could be a bad ground. Alot of weird things can go wrong if you have a bad ground.

 
Rep Power: 0

It may be the grounding since weird thigs are happening and it starts with random combinations of attempts. Presently if you press the break pedal with no key in the ignition the oil light, engine light and green immobilizer light comes on... and the oil light stays on.

The battery leads were checked, I even by-passed the negative since there was some corrosion on it.

Does anyone know of a schematic of the grounding locations?