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Originally Posted by larry4888
Terry, I probably should have mentioned that it is a 4.0 V6. Last night I used a test light to check the injectors. I had power at both wires on the injector. When I cranked it over the light dimmed on both wires and I could see what appeared to be a faint pulse in the light. I am assuming that this means that they are getting a crank signal. Also, that is correct as far as the fuel pump goes. When I turn the igntion to the on position the pump does not come on at all to pressure up the system. Is the PCM relay the same as the EEC relay? The EEC relay sits next to the pump relay in the fuse box under the hood. I will check it tonight, however I do remember unplugging it with the key on and hearing the relay click on.
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Yes, the EEC relay is the same as the PCM relay. This was the name given to it in the diagram which was for the 2.3L engine. I'll take a look at the 4.0L diagram and see if there is anything different between the two. Also, when the engine is not cranked, there would be +12V on both sides of the injector since the transistor(s) in the PCM is not being turned on to pull the return side low. However, there shouldn't be any pulsing on the +12V side to ground. Take your light and put it on the return side to the PCM (tan and white wires depending on the injector you check) and to ground. You should see the light pulsing while the engine is being cranked. I think it's strange that you're getting a pulsing light indicating the injectors should be opening and closing which should start the vehicle. Since you're not getting the fuel pump relay to pull in when you turn the switch to the on position, it's irrelevant about the ignition system working or not since the relay should pull in for a moment.
I had another thought...Go to the PCM, pull the connector, inspect the terminals and see if there is any obvious damage. Put the connector back on the PCM, pull it back off and repeat this several times in an attempt to clean the terminals. Then give it another try and see if the fuel pump will come on when the switch is turned on. If so, congratulations! Go and get some contact cleaner and clean the terminals. If that doesn't work, check those voltages and gnds at the PCM. If all that looks good...go get another PCM. Keep us posted with your results.