I hope I'm in the right section because this is my first post.
I have a 97 4.2 that started having hard starting problems a few months back and recently refused to start at all. When the hard starting began it would only start if I turned the key to the on position and waited about ten seconds then the engine would start. I never experienced other problems. Once the truck started it ran great. I figured it was a fuel problem but like an idiot I didn't mess with it due to lack of time. That went on for about two months and one day it wouldn't start at all. When we started trying to diagnose the problem here is what we found: all fuses and relays are good but I'm getting no fuel and no spark. I am also only getting 7 volts at the inertia switch (which has not been tripped) and the fuel pump. The fuel pump runs fine when we hook it to 12 volts. We have tried to read codes but the code reader says cannot connect to vehicle when it's connected to the port. My friend who is helping me says he is willing to bet it is a PCM problem. Sorry for the novel guys but I am trying to give as much info up front as possible. To summarize: no fuel, no spark, 7 volts to inertia switch and fuel pump, cannot read codes. Thanks so much and any advice is very much appreciated.

 

First check is to hear the pump run at key on no crank.
If yes cycle the key to run several times then attempt to start.
If start is now ok suspect the pump.
Check the fuel pressure in any event.
If all found ok there is some other issue.
If a Scanner cannot connect, suspect a blown fuse #12 on dash panel, bent or pushed pin in the DATA LINK connector.
Good luck.

 

Thank you for the reply. I just double checked the fuses and they are fine. The fuel pump does not run when the key is cycled. I will check fuel pressure tomorrow.

 

Is it possible that I could have had one or more damaged injectors and that eventually ruined the PCM?

 

Does the cigarette lighter/power point work?

 

Yes it it does

 

For fuel pump operation be sure to check fuse 19 and swap relay 4 in the engine bay box for retest.
Good luck.

 

We have tried this with the same results. Pump not running and only getting 7 volts. Again, thanks for all the tips.

 

You need to figure out where the other 5+ V is getting used at. Start working your way upstream on the wire/circuit

 

Ill try a few more things and let you guys know what I come up with. We have tried running down where the voltage drops to 7 volts but it seems like it just drops off to 7 at the inertia switch.

 

you should be able to unplug the inertia switch, wire around it (connect both wires on the connector) and see if you get good power on the pump

 

We tried to bypass the switch with no luck. Ill definitely try it again just to make sure it was done correctly.

 

I put a new battery and pcm in today and it fired right up with no hesitation. Thanks guys.