***Wooshing sound at low throttle?*** 97 F350 PS

[Gvilleracer]

Ok, so I go out this morning in the low 20's to drive to work. Now, I already know its going to take a few tries to start my truck and it does, about 5.
I give it a minuet to idle and it prolly needed more; but, I was running late. I backed out, put it in drive, and proceeded to leave the parking lot. This is when I first heard the sound coming from in front of the dash board, I beleive in the engine bay. It is easier to hear with the windows closed, throught the firewall. It was a wooshing sound like a vacume leak; but it sounded more like astrong blowing than sucking. It also does not pulse like its related to exhaust gasket or intake pulses. Its a smooth leak that comes on if I roll along at a low throttle.

It continued to do this for the rest of my 45 min trip. I can get it to stop by either letting off or adding more throotle. Anything above 50% throttle seems to shut whatever it is. Letting of does the smae thing. I cant hear the sound at idle and can't locate its source. It only happens when I was just giving it light throttle to coast along at a low speed or while in city traffic/parking lots.

Acceleration is fine, but, if I back out of the throttle a bit. Wait a second or 2 and I here the sound build up. The truck also seems to loose power and the exhaust note deepens a tiny bit. I dip the throttle and it stops immediatly. If I let off the throttle it also dies out in about a half second or so. I just can't accelerate slowly without getting the sound. I never heard the leak while the turbo was boosting.

If anyone could please tell me if I am going to be stranded on the way home; or, if there is some kind of idle/recerculation valve that could be malfunctioning due to the cold. This is definetly the coldest day yet for my truck to drive in. I have never had to drive the truck in anything below 40.

Thanks All.

[GiveMeFordOrGiveMeDeath]

I would say your EBPV is stuck shut, but then you'd have a huge loss of power and a wooshing sound. Hopefully a tech will jump on here soon, cause I don't think I've ever heard of this problem before.

[~CrazyDiesel~]

It's just the Warm-up valve (EBPV). It's a valve on the turbocharger which closes off the outlet of the turbo partially which stops the turbo from making boost and also puts a slight extra load on the engine. It's there to help the engine warm up and doesn't just look at the coolant temp, oil temp and ambient temp are also looked at to determine whether the valve needs to close. It's normal.

[GiveMeFordOrGiveMeDeath]

That's what I thought, but doesn't it usually bog it down at all throttle levels?

[Gvilleracer]

Thanks so much guys.
It did make the truck bog, but only slightly. And would quickly close when I laid into the accelerator.
This is the first time I have ever had to drive it in this cold of temps in 3years.

Oh, and I did notice it stopped the turbo from spooling at low throttle. As soon a sit shuts my boost snapped right in. Thanks.

I will wait for the weather to balance out and make sure it goes away.
It did get less noticeable after I had spent some time on the intersatate; but it never went away fully

[SIRed]

I wish I had seen this before I posted. I just posted in the general discussion board for the 99-03's. I've had what sounds like the same thing you are experiencing.

[MonsterEnergy37]

I have a 97 7.3 and my truck has been doing that same thing. but over the past few days it's been bad. I can sit in Park and bring the RPMs up to 1000 and then the engine will bog and the RPMs will drop to like 600, but then the RPMs jump back up to 1000 then it drops, and goes back and forth like that. If i roll my passenger window down i can hear the hissing noise from my exhaust. When i take off and listen out the window under light acceleration it hisses and almost growls. I wana know if its a normal cold operation or is my EBPV bad?? Please help, i'm real busy at school and have no garage where i'm staying in Illinois for school to look at much. Any help would be really appreciated

[Gvilleracer]

Well, Frome what I have learned from all these helpfull people is "its prolly not bad, its just not like everyone elses".
It seems that many people are having new issues with their warm-up valves (or their like me in Florida and are just learning they have one) but each story seems to have slightly different characteristics.

Mine was a lot like yours, but bringing the idle up in a parking lot prolly isnt a good test since there is no load on the motor the rpm will be greatly effected when the valve opens and closes as your noticing. Mine stayed this way for my entire 45 min drive to work. Then ran 100% normal later int he day when the air temps got above 40. Once your out driving is the real test. Some people are like me and it only opend at low throttle and will close as soon as I accelerate harder or let off the pedal completely, others say their stays open Full-Time untill the truck is at its desired temp. But, the thing they all seem to have in common is, the truck acceleration will suffer as boost will not produce with the valve open, and two, both of these are instances where the truck operating normaly and not a reliability issue.

But yes, it sure does freak us all out when something changes on our trucks, so I understand your alarm.



As for an update on my situation, we had our coldes night in Jacksonville last night. But, all was well with the truck this morning. It did not require any repeated cycling og the ignition and it fired up as soon as I hit the key and ran smooth and quite.

Why????....you ask...

Cause I had a freaking Block heater for the last 3 years and didn't know it!
I know, what a sad Ford owner. I never realized that plug above the oil filter was a heating element, always thought it was just a heavy duty temp/press sensore. It doest help that the previous owner seems to have purchased and extremely short aftermarket cord for it and tucked that into a nearby frame slot. When I decided to trace the line to see if it made its way up to the front of the truck, I gave it a tug and would you beleiv it there was a standard male plug. So I grabbed an extension cord, plugged it in, saw a tiny spark as I plugged it in that confirmed it was still working after all these years.

I got in this morning and saw that the "Wait to Start" went off much faster than normal even on a warm day, hit the key, fired right up, and I couldn't beleive it when I had warm air blowing as soon as I hit the control.

Thanks guys.

[MonsterEnergy37]

I've come to the conclusion that mine is opening and closing. It isn't consistant. It's like it doesn't realize when the coolant is at operating temp. But i'm just going to gut my EBPV, it wont hurt it and i don't need it, i plug my truck in every night seeing as it gets to the subzero temps. But Thanks.