Scanner in and out of communication

quadracer219 · Mar 22, 2016

Hey guys got a 99.5 7.3. Earlier today it started runnin like crap. Misfiring and pouring white smoke, almost a complete loss of power. Friend of mine was able to come over and hook up his snap on Verus edge scanner and we could not get it to communicate. Then randomly the truck started running fine. Drove it around and it acted fine. And we had communication with the scanner. Now anytime we would go to do a contribution test or a injector buzz test it will loose communication with the scanner and the truck dies out. When running the truck randomly die and loose communication with the scanner. And then it won't start and if we let it sit for say 5-10 minutes it will start up fine. Checked idm relay, checked all fuses and they were good. Checked pins on obd2 port and all are good. Checked connections at pcm and idm, no corrosion. Cps is good (gray one). Throws a bad IAT code. Tried unplugging IAT and made no difference in comminucation and it also keeps throwin a p1670 code continuously (Ef feedback signal not detected)

6.0 Tech · Mar 23, 2016

I have found that many aftermarket scan tools.do this to some 7.3s. I have even had the ids not work, and had to dig the ngs out of whatever corner of the shop it was buried in to finally get it to diag.

With the intermittent concern though, you may want to check the uvchs. Good luck...

quadracer219 · Mar 23, 2016

Would a ucvh cause a intermittent no start though? I can see the ucvh causing the rough runnin part. I did the passenger side already I need to do driver side still. This Mornin I fired it up, not really cold, maybe 50 degrees and if I brought it up off idle it had a slight misfire I could here. And a lot of white smoke on start up also. I'm hopin the misfire is comin from a bad ucvh, but once it warmed up misfire went away. And we still have the no communication thing and the random no start