Intermittent no start, intermittent WTS??

[highdesertstroke]

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.

[NoRalPh]

You must have an intermittent electrical issue connected with the PCM. Anytime you roll-on the key and Don't see a WTS, don't even bother cranking it over. The lack of a WTS is an indication the PCM isn't running and, without it running, you're just wasting the batteries

First thing I would think is, do you have a chip of some sort? If so, remove it as a test. Next, and I have no idea why this only happens on a restart, would be the fuses. Go over the ones related to the PCM (30-19-22 and probably others) when you have no WTS. The fuse most problematic is #30 because it also supplies power to the fuel heater and when shorted blows the fuse and prevents the PCM from powering-up (but if that fuse was blown it wouldn't run at all). Maybe unplug the Fuel heater now anyway...

Maybe the PCMs firewall connector? But, again, I'm thinking of a bad chip or chip connection being likely if you have one.

[highdesertstroke]

Originally Posted by NoRalPh

You must have an intermittent electrical issue connected with the PCM. Anytime you roll-on the key and Don't see a WTS, don't even bother cranking it over. The lack of a WTS is an indication the PCM isn't running and, without it running, you're just wasting the batteries

First thing I would think is, do you have a chip of some sort? If so, remove it as a test. Next, and I have no idea why this only happens on a restart, would be the fuses. Go over the ones related to the PCM (30-19-22 and probably others) when you have no WTS. The fuse most problematic is #30 because it also supplies power to the fuel heater and when shorted blows the fuse and prevents the PCM from powering-up (but if that fuse was blown it wouldn't run at all). Maybe unplug the Fuel heater now anyway...

Maybe the PCMs firewall connector? But, again, I'm thinking of a bad chip or chip connection being likely if you have one.

Yes the truck is chipped (TS 4 position) I swapped the PCM relay yesterday and so far so good. I will check the rest of the fuses tonite and maybe check my chip connection too and will see how it runs the rest of the week. Thanks!

[milwaukeeshaker]

Had this same problem for better part of a year. Never knew when the darn truck would leave me stranded. Finally started happening whenever the engine was warm. Pulled all of the relays and fuses found in fusebox under the hood, cleaned the contact points on all of them, used compressed air to blow out dust and crud in the box itself, then reinstalled the fuses and relays. This made a huge difference, but still had the no wait to start light problem, though not as bad as before. Changed the relay for the PCM in this same box, and viola! No more problems since.