Ok going full Dr house on this *****

lotzagoodstuff

Supporting Member
Supporting Member
Joined
May 19, 2007
Posts
2,726
Reaction score
668
Location
Carmel, IN
“Shut can” the fuel bowl heater. Nothing good comes from it. The last two different 7.3s I did a fuel filter change on I saw the heater laying unattached at the bottom of the bowl, just waiting to short out. Blank it out and it will be one more thing not to worry about :)
 

greenskeeper

Full Access Member
Joined
Mar 16, 2013
Posts
995
Reaction score
202
Location
PA
Yes the fuel bowl heater is still plugged in and intact and ignition switch feels tight no extra slop no more than usual
Disconnect the fuel bowl heater. It serves practically no purpose. As long as you treat your fuel in extreme cold you won't even miss it. Unplugging the heater is one of the first mods done to both my trucks. ZERO issues starting down to -20F without it (properly treated fuel, fully functioning glow plug system).

It's quite possible the heater is intermittently shorting out enough to "restart" the PCM, while at the same time not completely blowing the fuse (both the fuel bowl heater and PCM are on the same fuse).
 

Oledirtypearl86

Full Access Member
Joined
Sep 17, 2018
Posts
1,673
Reaction score
949
Location
Whitehall MT
Ok so update unplugged fuel heater and it seems better so I have been chasing wiring and looking for breaks and shorts then someone told the owner it sounds like a as the owner calls it the wired thing under the valve cover so now he wants new under valve cover harnesses good thing ihave a new dorman set on the shelf and the harness plugs so that's good
 

greenskeeper

Full Access Member
Joined
Mar 16, 2013
Posts
995
Reaction score
202
Location
PA
Ok so update unplugged fuel heater and it seems better so I have been chasing wiring and looking for breaks and shorts then someone told the owner it sounds like a as the owner calls it the wired thing under the valve cover so now he wants new under valve cover harnesses good thing ihave a new dorman set on the shelf and the harness plugs so that's good
UVCH won't cause the engine to quit. It will run rough on 4 cylinders, possibly won't start but definitely wouldn't be an intermittent failure. You'd also have a CEL and a code tripped due to the IDM shutting down that bank of cylinders.

BTW dorman is junk, go with OEM if possible.
 

aggiediesel01

Full Access Member
Joined
Dec 29, 2016
Posts
531
Reaction score
417
Location
Houston, TX
When mine was behaving similarly it turned out to be an internal issue with the power circuit inside the PCM. The main processor was losing power intermitantly. Mine would randomly, occasionally blip off and then come back until it finally got really bad and would stumble and restart and then shut off and then sometimes restart and sometimes not. I never got the WTS light when mine would blip or die. It also had other inconsistant acceleration issues and weird phantom things that have completely gone away since getting the PCM rebuilt.

Diesel Technology of Chattanooga has a test bench they can load test the PCMs and IDMs on to find failures and other than down time the testing is not too expensive.

 

Black dawg

Registered User
Joined
Jan 9, 2006
Posts
3,995
Reaction score
703
Location
sw mt
THe dorman stuff is pretty hit and miss........all of it, not just these vc harnesses.

I would get rid of the napa cps also, have seen all kinds of intermittent hiccups and different bs with those.
 
Top