Odd engine noise
Thread Starter
|
New User
Joined: May 2006
Posts: 7
Likes: 0
Odd engine noise
My 99 super duty is on occasion making a hissing noise at partial throttle. Noise is coming from turbo region with a slight power reduction and sounds like a large vacuum leak. Give a little throttle and noise disappears. Back off throttle and noise disappears. RPM reduction with noise onset and RPM increase with very slight throttle change. Any ideas ?
Laughing Gas
Joined: Jul 2003
Posts: 1,157
Likes: 1
From: Littleton, Colorado
Since the search is having issues, here's a quick response.
That's normal. There is an exhaust back pressure valve (EBPV) that restricts the exaust in cold weather to aid warming the engine up.
Since it goes away under acceleration and coast, yours is working normally.
Austin
That's normal. There is an exhaust back pressure valve (EBPV) that restricts the exaust in cold weather to aid warming the engine up.
Since it goes away under acceleration and coast, yours is working normally.
Austin
Cargo Master
Joined: Aug 2003
Posts: 2,332
Likes: 442
From: Eastern Washington
actually, it should open when the throttle is applied. Most likely you EBP sensor tube is clogged up, they need to be cleaned out occasionally. The sensor is front passenger side and has a small metal tube running aft, it should be removed for cleaning.
Unfortuanatly I still need to do mine and can't give you better instructions...
Unfortuanatly I still need to do mine and can't give you better instructions...
Post Fiend
Joined: Jun 2006
Posts: 5,497
Likes: 7
From: Central, Al
You will find the tube at the front of the passenger side exhaust manifold it runs up around several bends to the EBP Sensor located kinda behind the idler pulley. A set of crowfoot wrenches makes it easy (Not alot of room). Once you get the tube off spray it down with BrakeKlean and let it soak a little. I found that 0.95 square weedeter line works good for a reamer (tried the 0.105 and it wont make it past the last bend). I repeated the Spray, Soak, Ream cycle about 4 times and then reinstalled. The sensor is somewhat delicate but the BrakeKlean works well here also you just want to make sure you dont stick the reamer in to far and damage the pressure surface. (you will see when you get if off and look)
Before I did this i was seeing a max of 14psi backpressure and was noticings a drop in power and efficientcy after finishing the backpressure shot right back to the normal range and power and mileage came back.
Before I did this i was seeing a max of 14psi backpressure and was noticings a drop in power and efficientcy after finishing the backpressure shot right back to the normal range and power and mileage came back.
