99 7.3 Engine cutting off and on while driving

My7.3IsAZombie · Oct 14, 2011

I have an early 99 7.3 and when I'm driving at my engine will cut off and immediately come back on. RPMs drop to zero then rise right back up to where they were. It causes a pretty bad shutter in the truck and on some occasions the SES will come on. It seems to only do this when it is raining outside. Any ideas? I'll be scanning for codes and will post them. Thanks for the help!

BigAlsPSD · Oct 14, 2011

Couple of things I would look for would be CPS connection seal, maybe use some dielectric grease around the seal, possibly leaking windshield or cab lights.

PowerstrokeJunkie · Oct 14, 2011

Instead of checking the seal at the cam position sensor, just unplug it, and replace it. It is going bad. It is located right off the crankshaft pulley at 10 o'clock if you were looking through the front of the radiator at it

Mtack · Oct 16, 2011

That is exactly what my truck did when the cam positioning sensor was going out.

My7.3IsAZombie · Oct 16, 2011

I just installed a new one not too long ago...but it was from auto zone maybe I got a lemon. I'll try getting one from ford or international. Thanks for the suggestions. BIGALSPSD what do you mean when you say a leaking windshield/cab lights?

JLDickmon · Oct 16, 2011

My7.3IsAZombie said:
I just installed a new one not too long ago...but it was from auto zone maybe I got a lemon. I'll try getting one from ford or international. Thanks for the suggestions. BIGALSPSD what do you mean when you say a leaking windshield/cab lights?

water can get on/in the GEM & PCM and raise all kinds of hell

Clem1226 · Oct 16, 2011

need a new CPS...it is actually feedback on the ground from the wiper motor that is causing the issue but a good CPS wont care. If it rains again before you get a new CPS just don't use your wipers.

TrailerHauler · Oct 16, 2011

Sounds like its most likely going to be the CPS, but it wouldn't hurt to check for moisture on or around the GEM module. Water getting near the GEM module causes some weird problems.

Arisley · Oct 17, 2011

TrailerHauler said:
Sounds like its most likely going to be the CPS, but it wouldn't hurt to check for moisture on or around the GEM module. Water getting near the GEM module causes some weird problems.

:whs:

And if you are running a CPS from Autozone, you are lucky to have it last a couple of months. They are famous for being bad out of the box.

BigAlsPSD · Oct 18, 2011

My7.3IsAZombie said:
BIGALSPSD what do you mean when you say a leaking windshield/cab lights?

As others stated, water can get into the GEM or Fuse Box or PCM even, from a leaking windshield or Cab lights. I'm with the others too, definitely get the autozone CPS out of there first. They are known to cause issues, and you might be able to get one free from ford if you haven't had the recall done.

Curtis@Vision Diesel · Oct 18, 2011

Arisley said:
:whs:

And if you are running a CPS from Autozone, you are lucky to have it last a couple of months. They are famous for being bad out of the box.

I have even gotten bad ones from ford out of the box.