Cougar

The ignition circuit should tie to the plus side of the coil not the minus side. I think the power wire to the coil is black and it should tie to the plus side. Once you verify that is ok then make sure there is voltage on the minus side of the coil also. If there isn't any then the coil is open or the CAS is making a ground connection to it. Remove the wire to the minus side and check for voltage again. If you now have voltage then the CAS may be bad.

What about the voltage to the coil?

Check to see if you are getting voltage on both sides of the ignition coil when the ignition is on. If you have voltage on both sides then see if there are voltage pulses on the minus side of the coil when you crank the engine. If there aren't any pulses then something is wrong with the CAS circuit. If you are sure the things you replaced are ok and the wiring to the ECU is ok then the ECU would seem to be the suspect.

I didn't realize you had an external regulator. I was thinking of an internal one. From what you say it seems to me that the regulator voltage isn't set correctly. Is there a way to adjust that? Like a screw adjustment on the relay. Have you checked for AC voltage across the battery while the alternator is running? There should be less than .1 volts.

You have found the trouble area. There should be near battery voltage on that connection when the alternator is working. The problem with the exciter/field wire may be due to a bad connection on the wire coming from the warning light, the warning light itself may be bad, or there is a bad connection to the light in the socket. Check to see if the battery warning light turns on when you turn the ignition on and the engine isn't running. If the light doesn't turn on then remove the plug on the back of the alternator and use something like a pin or piece of wire to make a connection to the field wire and a good ground point. If the warning light still doesn't work you need to find out why that is. If the light does turn on then the alternator has a problem inside it.

If you haven't checked the fusible links already that may be a good thing to do also.

The Main Relay supplies power to the ECU and the fuel pump relay if I remember correctly. SBF-2 is one of the slow blow fuses in the Main Panel under the hood.

As far as power connection for the leaf contacts go I'm not sure. If there is only one wire going to both of them then both would have power tied to them I would have to think. One side may go to ground if there are two wires.

Make sure voltage is getting to the park switch contacts. No voltage there could cause that kind of trouble. The control for the delay wipers may be bad but you would need to check the wiring to it first.

Can you hear the pump run briefly when you turn the key from OFF to ON? Another thing in case you aren't aware of it. If the ignition system isn't working then fuel pump circuit is shut down when the ignition system is set to the ON or RUN mode.

Is it possible the hose lines to canister got connected up wrong when the engine was put back in?

If it is a bad MAF sensor causing the trouble shouldn't disconnecting the electrical connection to it allow the engine to start up? I seem to recall others using that trick in the past.

The main wire of the alternator tieing to the battery is the output wire, not the exciter wire. The wire tied to the warning lamp in the dash should tie to the exciter. The lead supplies power to the exciter through the warning lamp and then when the engine starts the exciter builds a charge up in the field windings of the alternator. When field builds up the alternator starts working and also backfeeds a voltage on the lamp wire. That causes the warning light to turn off when the alternator is working correctly. If there is a problem then that voltage drops and the warning light turns on. That circuit is also tied to the warning lights and is how they are tested when the key is turned to ON and the engine OFF. Another lead on the back side should tie to the regulator so it can monitor the charge state of the battery.

Try spraying some starter fluid into the intake to see if that will help the engine fire up. If it does then you know you have a fuel delivery problem. If that doesn't work then check the ignition system for a problem.

A reed switch is usually used with in conjuntion with a magnet that controls the switch action.

If I remember correctly I seem to recall reading about a warning on doing a resistance test on O2 sensors as it will damage them. They are a voltage generator basically, though it is a small voltage. The best way I know of to test them is to check the voltage of the device under working conditions. A meter works but a scope is the best thing to use. I know not many folks have one though.

As others have stated already a alternator can have excessive ripple voltage that will cause crazy things to happen with the electrical systems. The DC voltage can still appear to be fine, it is the AC voltage component that is messing with things. A simple way to prove the trouble is coming from the charging system is to disable the alternator by shutting the engine off and then remove the plug on the rear side of the alternator.That will kill the exciter and the charging action. Restart the engine and if things now return to normal by just running off the battery you know what to do to fix it.

You could try starting the engine using starter fluid and keep it running with short bursts for about 15 seconds. Hopefully the engine will be able to run on its own by then.

See if you can locate the relay since you can hear it. Also see what color the power wire is going to the horn and see if you can find a matching wire on the relay socket. The relay may be bad so try swapping it before chasing wire trouble.

Try pin 37 and 42 to see if that does it.

You're welcome Rich. Glen

My info shows pin 31 of the ECU for the green connector and that ties to pin 42 (GND) to go into the test mode. To clear the memory connect 39 and 42.

Check the fusible links if you haven't done that already. If they are ok then make sure voltage is getting to all the fuses. Does the engine start if you don't apply power to the areas you mentioned? If not, the Ignition Relay may be at fault.

It would help to know what the year is and what model car you have.

They should have a relay. Also check the fuse for that area and make sure it is okay. Since the trouble was intermittent the relay is the best bet.