Check Engine Light Ford OBD I Code 18

The computer sends out a timing advance correction to the ICM over the SPOUT wire and then looks for the change on the IDM wire.

IDM - Ignition Diagnostic Monitor
SPOUT - Spark Output Signal from EEC/PCM
ICM - Ignition Control Module

You might check the ECT or the IAT sensor for your problem.
Also check the SPOUT/IDM wire going to ground.

ECT - Engine Coolant Temperature sensor and it has two wires on it.
IAT - Intake Air Temp

IDM (feedback) is a Dark Green with a Yellow stripe wire on the distributor connector.

IDM is pin 4 on the 60 pin ECM connector.

Generally all vehicles from 1996 and up have an OBD II computer. The Major problem when it comes to OBD II is that you can no longer acquire the trouble codes by counting the flashes of the Check Engine light like you could on earlier OBD I vehicles. You can take your car into a local high-tech service shop, where the minimum charge for computer diagnostics and engine diagnostics might cost you somewhere into three digits. Or you may want to learn about OBD II systems. in order to do so you will need an OBD II scan tool. I have already done the research for you and located several different scan tools for you to choose from. If you already have the code and need to know what it means check out our complete list of OBD II Codes Here.

 

OBD II scan tools connect to the vehicle's computer through a connector under the dash by the steering wheel.

 

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