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The engine computer in the passenger compartment powers the injectors on most modern cars. Many Fords have this behind the glove box liner, or under the passenger seat. I haven't worked on a 9x Thunderbird. First remove the injector connector, put two probes of a high input impedence multimeter (digital ones are high impedance), put it on the 200vAC scale, and run the engine. If your reading is zero, you probably have a bad connection somewhere or a blown computer. Make sure you do not cross the probes and short the computer output with the engine running, as this will destroy the computer board. Rigging up the probes with electrical tape before starting the test is a good idea. While you have the meter out, measure the ohms on the #1 injector, and then measure the ohms on another (good) injector and make sure they are the same. Also measure the ohms on the bad cylinder injector and make sure it is not 0 to 2 ohms to ground (exposed metal on the injector). If the injector on the bad cylinder measures different than the others, replace it. If your injector plug AC voltage reading was zero with the engine running, then you have a corroded connector or a blown computer. Most cars have both an edge connector at the edge of the computer board in the passenger compartment, and another master connector in the engine compartment. Corrosion is more likely in the engine compartment. Look for a bundle of wires about 1" in diameter running from engine towards the dash. If it runs through an under hood connector, it will be in a plastic housing attached to the fender wall or firewall. You may have a bad (corroded) connector due to salt spray or rain spray. Buy a spray can of contact cleaner. If you buy the kind that is labled "hexane" (or any other -ane), be sure to do not smoke or run the engine or a heater or appliance or trouble light while you are using it. "Hexane" is old fashioned gasoline in a spray can. I bought some at a famous lumberyard chain once- it is very dangerously inflammable, but effective. Contact cleaners that contain chemicals with names like chlor- or brom- are safer for you the user, but more dangerous for the ozone layer. If your 13 or under,and your Mom has a good lawyer, don't inhale any spray can. If you feel brave, remove the latches on the engine compartment connector, pry it back enough that you can see the pins, spray them with the contact cleaner, then reseat the connector. If you break the plastic connector, or a pin, you will have to buy a new $400 (?) wire harness, as junk yards typically chop this harness at the connector when removing the engine. So be careful, and understand the risk. If this solves the problem and gets you ac voltage at the injector, great. If not, spraying the edge connector at the computer board may help. Before pulling the connector off the computer board, be sure to disconnect the battery, and also ground yourself to some metal that shows zero ohms to the battery negative- winter is the time when static electricity on your body and clothes is most likely to blow up the computer. Hope this helps. If not, a new computer board may be required. A word on computer boards: "repaired" boards often contain the same problem that they were sent to the shop for, as the testing the shop does is limited, and probably does not include a function test at all temperatures that you car is likely to experience. The best computer board is one that you pull yourself (grounded at the time, and put it in a static proof baggie to transport home), from a car that was recently mangled in a high speed collision.
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