7.3 running weird
Thread Starter
|
Senior User
Joined: Nov 2016
Posts: 140
Likes: 0
7.3 running weird
Hey guys. Ive only put about 6000 miles on my truck. My problem just started yesterday. When i start my truck ot idles great. Let it warm up a bit then hit the highway to work. When im shifting through the gears if i leave it a rpm for a few seconds the truck loses power bogs down. When i push the pedal to the floor it goes away. I sethe cruise at 70 and itll do it. Bog down and make a hissing sound. Fights with itself to stay at that speed. It doesn't blow black smoke. So i dont think its a boost leak. Did change the oil and fuel filter almost 2000 miles ago. Any advice would be great. Thanks fte.
Postmaster
Joined: Sep 2007
Posts: 4,195
Likes: 6
From: Medford Oregon
Exhaust Back Pressure valve (EBPV) is closing trying to warm up the truck quicker. This is normal but concerning if not expecting it. The hissing sound is the valve closing with exhaust rushing past it. Once engine oil temperature is up, 175 degrees on my 97 the PCM no longer commands the function. This usually only occurs on cold mornings probably around ~32 degrees or below.
Believe it or not the function does really help warm up the engine quicker but can be a bit of a pain. Most just disable the function by unplugging the two wire connector just in front and below the turbo. That will disable the valve and it doesn't hurt anything. I ran it disconnected for awhile but reconnected it because it didn't cause me any concern.
Hint: If you run the truck a bit until EOT is 135 degrees or above then turn the engine OFF then ON the function is disabled. PCM uses EOT, AIT and power demand to determine when to actuated - de-actuated the valve The temperatures posted vary by year of truck and are for my 97.
Believe it or not the function does really help warm up the engine quicker but can be a bit of a pain. Most just disable the function by unplugging the two wire connector just in front and below the turbo. That will disable the valve and it doesn't hurt anything. I ran it disconnected for awhile but reconnected it because it didn't cause me any concern.
Hint: If you run the truck a bit until EOT is 135 degrees or above then turn the engine OFF then ON the function is disabled. PCM uses EOT, AIT and power demand to determine when to actuated - de-actuated the valve The temperatures posted vary by year of truck and are for my 97.
Thread Starter
|
Senior User
Joined: Nov 2016
Posts: 140
Likes: 0
Trending Topics
Post Fiend
Joined: Dec 2009
Posts: 15,505
Likes: 18
From: Livoina,La
Also if you have a faulty thermostat (stuck open) it may never get to operating temperature in the winter.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Postmaster
Joined: Sep 2007
Posts: 4,195
Likes: 6
From: Medford Oregon
OP: Even with a good thermostat it is hard to get the temps up in cold winter mornings, unless working the truck. Guess that's why Ford developed the EBPV system. The problem with the design is if you need immediate power to get out of a situation and the valve is closed some % wise it may takes a few seconds to recover (open fully) because it's controlled by engine oil pressure hydraulically. A slow moving valve indeed.
Thread
Thread Starter
Forum
Replies
Last Post
sonofdixie
1999 - 2003 7.3L Power Stroke Diesel
18
Apr 11, 2015 06:37 AM
Highmark18
1994.5 - 1997 7.3L Power Stroke Diesel
11
Nov 29, 2006 11:43 PM