help 1999 7.3 hissing under low acceleration
 

my 1999 is hissing under low acceleration,hot or cold,
i changed the EBV and tube
turbo pedastel / base new o rings,
muffler and pipes ,stock

its intermitent at low rpms,feels as though it looses power till hissing goes away
the turbo was inspected and is in good condition as far as the impelar and bearings.
changed oil,fuel filters,all intercooler hoses and turbo hoses seem to be tight no carbon,no carbon on down pipes donuts,new glow plugs,starts and runs great except for the hissing and power loss
HELP PLEASE

---AutoMerged DoublePost---

OH and there are no codes !!
on snap on scanner,comes up clean!

There should be no codes... Your truck is doing what it should under light accel and when idleing.

Your Exhaust Back Pressure Valve is closing, causing the noise and also putting your motor under more load to help it warm up. I'm betting you live somewhere that it does not get cold very often and now it is???

Completely normal.

im in nj
 

cold about three months a year,my tem only gets up about a third of the way,before half way mark,
WOULD A HOTTER THERMOSTADT HEL THE ENGINE RUN AT A NORMAL OP TEMP,IF SO WHAT DEGREE THERMO SHOULD I RUN,
THANK YOU FOR THE HELP

Most have been running a *203 that I've seen on here, mine is a *195. It was only 3 degrees this morning and mine was perfect ( temp third of the way up, and the heater blowin hot enough to cook a deer shoulder:tu:)

IM GOING TO UP THE THERMOS ON MY TRUCKS ALL 3 HAVE SIMILAR ISSUES,WITH THE EBV ,STAYING OPEN TO HEAT UP THE ENGINE,THANKS FOR YOUR INPUT,

dose it sound like its sucking air in the exahust, mines been doing that lately just wondering

Yes, thats it.

It closes to build back pressure, not opens. FYI

the sound is more like the pressure releasing somewere under the hood,like a prolonged blow off valve sound,long hiss until you remove your foot from the pedal,at low rpms,

Its your EBPV...