Engine or Tranny?
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New User
Joined: Feb 2008
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Engine or Tranny?
Hey guys,
My truck a 97 f-250 PSD 4x4 supercab has recently been showing some unusual behavior intermittenly. I have been noticing some times when driving around town with very light throttle I get a wooshing noise and the trucks feels like it is holding back little. The sound and the hold back disapears if I tip into the throttle more or the tranny shifts out to the next gear. It sounds just like a vacuum leak or the blower fan on high. I checked the blower fan and I just had my scheduled tranny fluid change which had no effect on this noise. I am having a hard time deteriming where this could be coming from, any thoughts?
My truck a 97 f-250 PSD 4x4 supercab has recently been showing some unusual behavior intermittenly. I have been noticing some times when driving around town with very light throttle I get a wooshing noise and the trucks feels like it is holding back little. The sound and the hold back disapears if I tip into the throttle more or the tranny shifts out to the next gear. It sounds just like a vacuum leak or the blower fan on high. I checked the blower fan and I just had my scheduled tranny fluid change which had no effect on this noise. I am having a hard time deteriming where this could be coming from, any thoughts?
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New User
Joined: Feb 2008
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Thanks for the advise.Sorry guys I am still a little new to diesels, but plug the backpressure valve and leave it unplugged? How does the back pressure valve opperate? Why does it do it only intermittenly(if you can answer that)?
Lead Driver
Joined: May 2007
Posts: 8,608
Likes: 13
From: Belair md
its design is to restrict the exhaust exiting the turbo to make the engine work harder, this is supposed to help the engine warm up faster in cold temperatures. it will only engage when the throttle is under 1\4 and the engine oil temps are low enough to constitute operation.
it works by using oil pressure from the turbo pedastool to close a butterfly valve on the outlet of the turbobetween the housing and the downpipe, you cant miss it, its got a rod coming out of the aluminum housing going to a clip on the pipe
it works by using oil pressure from the turbo pedastool to close a butterfly valve on the outlet of the turbobetween the housing and the downpipe, you cant miss it, its got a rod coming out of the aluminum housing going to a clip on the pipe
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That makes sense, so it is similar to the old thermal spring activated butterfly valve at the end ot the exhaust manifolds used on old chevy V8s to aid warm-up by restricting exhaust flow.
Thanks for the info I will unplug it before I leave my office.
Thanks for the info I will unplug it before I leave my office.
Cargo Master
Joined: Jul 2006
Posts: 2,756
Likes: 38
From: Nampa, ID
He said the "C"-word...LOL.
Welcome to
I was having the same issue and received the same advice. Popped the hood, found the plug, unplugged it, and no problem since. These guys are great.
Welcome to
I was having the same issue and received the same advice. Popped the hood, found the plug, unplugged it, and no problem since. These guys are great.
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Yeah I said the "C" word, and the reason I knew that was because all I ever did was work on those pieces of junk. I have been blue oval loyal for 17 years and counting!
That great to know it solved your problem and should solve mine, yeah the guys on this board are great!
IDMooseMan I saw your accident pics, made me cry I hope you get her fixed up back to original glory.
That great to know it solved your problem and should solve mine, yeah the guys on this board are great!
IDMooseMan I saw your accident pics, made me cry I hope you get her fixed up back to original glory.
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