intermittent no start

[high desert stroke]

So, about once a month my 99.5, 7.3 decides it doesn't want to start. It will run fine all day. I'll shut her down, then get back in to fire her up and then NO WTS light and she'll just crank and crank and not start. I'll cycle the key a few times, nothing. Wait 5 minutes, then WTS light finally comes back on and it'll fire up. I did Stancor mod about a month ago and it still does it. Happened twice today and its getting longer and longer before it decides to start. Any suggestions? I'm a new owner of PSD's and searched for a solid hour but couldn't find this exact symptom.

 

[Arisley]

Check the PCM relay.
No WTS light usually means no power to the PCM.
Intermittant usually means relay.

 

[high desert stroke]

Is that the relay on the passenger side fender?

 

[Arisley]

No. Driver side under hood fuse box. One of the three little brick ones. If you have a owners manual, it will tell you. You can swap it with the blower motor fan relay to troubleshoot.

 

[high desert stroke]

Great thanks, off to check it!