We have a 91 Honda Civic in which we dropped a jdm vtec engine and ECU
in it. You know, the kind of conversion many have done before. But,
now we are stuck with the following problem: when we start the engine,
it will hunt between 1K and 2K rpm. Incidentally, the tach only works
if you turn the headlight off. On the top of that, we can take the key
off the car and it will not shutdown. So, where should I start
checking the electrical on this car?  We have spend a day testing
every wire that goes from and to the ECU and were able to account for
each one of them.  We have also tested the ECU in another similarly
converted car. It worked fine.

Now, I learned this weekend that my friend -- the car owner -- had to
cut some of the wires that lead to the bumper/headlight for one reason
or another. But he supposedly has soldered them back. However, at this
point I wonder if that could have caused the situation and how. If you
have not noticed, I am shooting in all directions right now.