Re: 1800 not starting? (redhotjose9)
Most starters and solenoids are grounded through the engine block. On most solenoids there should be two threaded post and nut connections and one or more male plug in (or very small threaded post and nut) connectors. The + (always hot) lead from the battery goes to one of the threaded post connectors, and a jumper lead from the other to the starter. The male plug (or one of them if more than one) receives a wire (+) which goes to the ignition switch, and is only hot with the switch in the "start" position. With the ignition switch in the "start" position current is sent through this wire to the solenoid to activate it, which does two things: it closes the circuit between the two threaded posts, thus activating the starter, and at the other end of the solenoid it activates a lever which engages the starting gear (drive) on the starter with the ring gear on the flywheel, thus (hopefully) turning over the engine.
There are four primary tests for most starting systems:
1. Make sure the starter mounting bolts are tight because if they aren't, the starter and solenoid may not be sufficiently grounded, or the starter drive gear may be either jammed in the ring gear or not making contact with it.
2. Turn the key to the "start" position. If the starter turns over but doesn't engage the ring gear, then there's probably a problem with insuffient voltage to the starter or a problem with the solenoid or starter drive. (See 1.) If it doesn't turn over but you hear "click," the solenoid's probably OK but either there's not enough battery voltage getting to it, or an internal problem in the starter.
3. Using a voltmeter, check for full battery voltage at the post and nut connector which receives the + lead from the battery. If there's no voltage reading or its not the same as the battery voltage, the lead is bad or the battery connection is dirty. If the reading is the same as the battery, check for voltage at the post and nut connector for the bridge lead to the starter; there should be no voltage here unless the ignition switch is in the "start" position. If there is, then the solenoid is broken with the contacts closed or it's jammed in the "on" position. This is dangerous and will also rapidly drain the battery and may damage the wiring, so disconnect it immediately before going any further.
4. If the other tests come out OK, with the ignition switch in the "start" position, test for voltage at the plug connector for the lead from the ignition switch. This may or may not be full battery voltage, depending whether or not the system has a ballast or similar device which limits the voltage to the solenoid. If there is no voltage at this connector, then it's probably a switch, wiring or ballast (if any) problem. If there is voltage but there's no "click" from the solenoid, or there is but the starter won't turn over, then either or both need to be replaced (or sometimes, the starter is gummed up with crap and needs a good clean-up and the bearings and starter drive re-lubricated).
As already noted, these are generic hints and they're also off the top of my head late at night, so I may have missed something or your system may be slightly different.
Almost forgot this basic hint: make sure all the electrical connections are clean and rust free.
And another one.
If the starter turns over and you get a grinding noise, first go back to 1. above, and if that doesn't resolve it either the starter drive gear or the ring gear on the flywheel is buggered up. The first only means pulling the starter to fix or replace it, and the second means pulling the tranny, clutch and flywheel in order to replace the ring gear.
