Code problems

[Dirk611]

New to forum and diesel trucks.
Have 1999 f350 7.3 240K miles
Service engine light on
Threw codes for ICP sensor and old code for cam sensor and exhaust sensor malfunction.
Replaced ICP sensor and cam sensor.
Erased codes.
No codes for 100 miles, then P0470 came up again.
What do you guys think.
Hooked vacuum tester to turbo - flap moves.
Do you think ex. pressure tube might be clogged??
Do you think plug under valve cover loose??
Possible ex. sensor bad??

Thanks:
Dirk611

[mrgrimm]

Hey I had that code show up when my CPS was giving me problems and I took off the tube and cleaned it and haven't had that P0470 code again. It's a free easy attempt that worked for me...BTW the tube and sensor at the end was packed full of soot.

[Dirk611]

Thanks for the reply !!
Cleaned tube and replaced sensor- Drove no code !!
I think I have found my problem- I have a short in the wiring junction plug. When I shake the wire coming from fuse area over the valve cover the truck will die.
Have separated the plug and cleaned - now truck will not start. Turns over but acts like no fire. Getting voltage to starter, inj. solenoid , ac comp. so plug is making contact.
Question-- Will truck run with no boot between air filter and turbo.(what is sensor in air box??)I have removed boots to get at wiring.
Thanks
Dirk611

[Dirk611]

Answered one of my own questions.
Yes truck will run with no boot !!
Truck has been sitting for about two hours - meaning me not working on it !
When out to turn engine over to see if tach was moving (check crank sensor) and it started right up. Maybe a relay overheated? Wires are still untaped (where I was searching for broken wire) moved wires around engine did not die.
Any guesses ??

[mrgrimm]

The sensor you asked about is the air intake temp. sensor. If unplugged I think the truck will still run, but goes into a mode that is not as effecient as with it plugged in. I believe the sensor calculates air temp and gives the PCM that info. so it can determine proper fuel ratio and so on...but I may be wrong.