Ford Repair: self timing test, timing test, timing changes

Question
Hi Dennis, During the computer self test on my 1984 4.9 F150 6cyl it passes koeo but does not do timing check. Am I doing something wrong? Comes up code 18 in memory indicating a short. Hope you can help me.

Answer
Timing check is not done during KOEO, did you do the KOER? That test is where the timing check is done. The alternative is to disconnect the spout and check base timing. The KOER test verifies the computers ability to actually control timing. I don't use that one much, to the chagrin I'm sure of my Ford instructors of the past, however if the timing changes with the spout in or out, you can be pretty sure the computer is controlling timing, usually with a base of 10BTDC and a computed idle timing of 17-20BTDC (approximately, varies by model and engine).

Code 18 in memory indicates a lack of tach signal, or ignition diagnostic monitor, acutally the same thing. This is most commonly caused by a fault in the ignition module. If the connector on the ignition module is greenish, this could also be part of the problem due to corrosion. The connector should still be available from  Ford.