Hello... I hope someone can offer some suggestions to this problem. We have a 2000 Ford Escort that refused to start on Christmas day 2006. The battery was in bad shape with a great deal of corrosion and one post was loose. We replaced the battery after Christmas but the car still would not start. Because the battery was removed and replaced all of the diagnostic codes were wiped out. So far two mechanics have given up on it and it is now with a third mechanic.
According to our puzzled mechanic the car is not getting any spark or fuel. The problem is not the fuel pump. Also it is not in the modules or relays or fuses. The computer has also been replaced but still no luck. Any ideas what else should be checked?
Any suggestions are greatly appreciated. Thanks.

Basically, you want to follow a methodology similar to what's desribed in sections A and B below:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-honda-civics-46563.html

If you methodically run all of the tests, you will identify what's wrong.

. Test all under-hood and under-dash fuses with a test light or multimeter:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-honda-civics-46563-3.html#post252145

. Make sure main engine grounds are in good shape and clean.
. When you turn the ignition switch ON, does the CEL come on and then go off after 2 seconds? During this period, do you hear the fuel pump run?
. Crank the engine for no more than 20 seconds and see if you can make it throw a code. It could tell you what's wrong.
. Start testing for voltage at key junctures. Check the ignition switch and harness. Test for voltage from the under-dash fuse box to the fuel relay connector, when the ignition is turned ON. Find out what terminal to test. Test for voltage from the ECM to key sensors, such as the Throttle Position Sensor. Make sure the main ECM ground is good.
. Many Fords have a Constant Control Relay Module (CCRM), mounted near the battery. It controls power to the Electronic Engine Control (EEC) power relay and the fuel pump relay (under-hood fuse/relay box). If you are not getting spark or fuel, I suspect your problem could be in this area.