Cougar

A little sparking is normal when you connect the battery. Normal current draw when the car is parked should be around 25 to 80 milliamps, that is used for memory power. How do you check the grounds? Did you just look them over or use a meter to check for voltage drop across them? The ECU grounds are under the dash I think.

Thanks for the clarification, I misunderstood your post. Check the voltage at the IAC solenoid and see what you have. If it is less than 12 volts then there is either a bad connection on the line or the relay may be bad, as you stated. Checking the voltage on the line will tell you where the problem is. If the voltage is ok at the solenoid then check the resistance of the solenoid coil with the unit disconnected from the circuit. It may be open circuited and need to be replaced.

I recommend you first find out why the voltage is not getting to the MIL light from fuse #15. Also check the grounds going to the ECU for any problem. A bad ground connection will cause this kind of thing to happen.

Nipper is correct. The test light should turn on when you are on the wire opposite the ECU connection since that wire should be tied directly to power. If you have proved that power is available after the fuse using your test light, then the wire connection between the fuse panel and the light is broken. Since you state that the light is turning on at the ECU connection, and I assume that the test probe you are using is being clipped to ground while doing this, it means the ECU is not switching to ground. If you are testing the connection when the light is supposed to be ON then it seems something is wrong with the ECU also. In the past, I have replaced damaged IC's in the ECU that control that circuit.

The main output wire tied to the battery should also run through a fusible link to protect that wire since it is tied directly to the battery.

It appears you have a bad connection to the purge solenoid somewhere. I would suspect the connection at the solenoid first.

I can't think of anthing with the wiring that would do this unless the supply voltage is too high. Have you checked that? If that isn't more than 14.8 volts then you might try another brand of bulbs.

From what I have seen in the past, the CEL light is grounded through the ECU. My info shows that the light is provided power through fuse #15 and ties to the light. The return for the light goes to pin 58 of the ECU. Check your fuse panel for a bad fuse. The same fuse also provides power to pin 7 of the check connector in the center of the instrument panel.

To measure the voltage of the sensor place your probes across the sensor connections while it is connected normally and cranking the engine. Also check the connections to it for a bad connection. It may be that this problem is due to just a bad connection contact. You may be able find a used sensor from some of the members here. Check the Market Place forum.

You should hear the the pump turn on briefly when you turn the key to the RUN position. If not, then try starting the engine, turn the key to OFF, and repeat the step. To see if you have a fuel problem try spraying a small shot of starter fluid into the intake and see if the engine trys to run then. If that doesn't work and you have good spark then it would seem there is a timing problem or one of the timing belts is broken. Check the compression of at least one cylinder on each side of the engine. IIRC you stated earlier that the disty is turning and so that would mean that one (driver's side??, not sure which one ties to the disty) belt at least is ok.

I would check the crank sensor and cam sensor AC voltages while trying to start the engine, at a time when the engine is working ok. Write down the results and hopefully you can get a baseline to compare to when the engine won't start. The problem very well be one of the sensors. I doubt the ECU is bad but it isn't out of the question.

Along with the others I too would suggest you get the battery and the alternator checked out for a problem. Like Skip mentioned, it does sound like some of the diodes are bad in the alternator. Along with that make sure the battery connections have been cleaned using a battery brush. There may also be a problem with the accessory power wire that feeds power to the fuse panel. This is the smaller lead tied to the positive terminal. The voltage gauge in the dash will normally read about 1 volt lower than the battery voltage due to wiring losses. If the voltage drop is more than that then you need to check the wiring between the battery and the fuse panel for a problem. The fusible links connections are the first spot to check.

First check the fusible links and the fuses for a problem. If those are fine then check to see if the charge warning light comes on when the key is turned to the 'RUN' position. If the light doesn't turn on then make sure the bulb is good. If the bulb is ok then start the engine and check the voltages on the wires tied to the alternator. They all should be near the battery voltage. If a line is low then that lead needs to be checked as to why it is. If you have a white/red wire, I think that one leads to the warning light. One thing to note. It is not a good idea to run the alternator without it being tied to the battery. The battery helps reduce noise pulses from the alternator which can possibly damage electronic circuits. A lot of folks do this though and get away with it.

For the injector problem I would check the wiring to the #2 injector and see if there is a problem with it. You should be able to get a pin number from your print that it ties to the ECU at. It sounds like there is a break in the circuit to the injector somewhere.

Try spraying a small amount of starter fluid into the intake and see if that will make the engine fire briefly. If the engine fires up and then dies, check the injector pulses.

Look for a device that is about 1 inch in dimensions and plugged into a socket. The socket may be blue.

The info for a '88 model shows it to be near the steering column, connected to a blue connector.

The voltage is low alright. You need to back track the line to see where the problem is. It may be the fuel pump relay that is causing the voltage drop.

You stated that the bulbs are dark and that would mean they are probably blown out. I would guess that they are replaced by pushing in on the bulb and turning it but I really don't know for sure. If the base is round then that is what I would try to do. If the base is flat they may just slip out.

Yes, code 27 is saying that there is a problem with the wiring going to the sensor. It could be a short but more likely it is due to a bad connection somewhere.

Using a test light probe or meter and the ignition ON, check to see if you have voltage on both sides of the coil when this trouble happens again.

The cigar and mirror circuits are shown in my service data to be on the same fuse, #14. If you also found #5 blown you most likely found your trouble. If the fuse doesn't just blow again at least.

If the problem wasn't due to a bad connection on the top side of the fuse holder then the trouble may be on the bottom side.

Good job Rysbrnr. You used one of my favorite tricks to find intermittent trouble. It's amazing what you can find using a screwdriver handle. Thanks for the update.

The problem is most likely in these areas, assuming the battery connections have been checked already. 1. Check the fusible links for a bad connection. 2. The ignition switch is flakey. 3. The main accessory power buss has a problem. 4. The battery has a internal connection problem.