Putting a 97 pcm into a 95 to test?

[wildstang]

Hi. My son has a 97 ranger 4.0 5sp 4x4 and Saturday he was about a mile from our road and he said the power dropped and just as he got onto our road and stalled. It started but stalled and he said there was some smoke maybe out the vents. Anyways towed it home. It cranks but there wasn't any fuel pressure, so I thought the pump crapped out. Unfortunately not that easy. At this point I have diagnosed that the pcm relay in the power distribution box is not getting the key on signal voltage to activate the relay, and neither is the fuel pump relay. Also not getting any spark to the plugs. I can put power to leg 65 of the pcm relay and it will kick on the pump but still no spark. I have a parts 97 mazda b4000 that is 4L 5sp 4x4 and the pcm is almost the same numbers. I put that into the 97 ranger but still no key on voltage to the pcm or fuel pump relays. I put the b4000 pcm back into the b4000 and hooked up a battery and I do get the key on voltage to the relays. I don't think it is pcm related, but can I put the 97 ranger pcm into my 95 ranger with 4L 5sp 4x4 to see if it will start the 95 to rule out pcm?

 

[19Walt93]

Nope. A 95 would be EEC IV and a 97 is EEC V/OBD II.

 

[wildstang]

Thank you 19Walt93. I was hoping that wouldn't be problem but is. I can put the ranger pcm into the mazda and see if the key on voltage is sent to the pcm relay. If it does, it would seem to me to be an issue from the switch to the power distribution box?

I am correct to assume that the key on power goes to the pcm relay, then that sends power to the pcm?
Thank you