This is topic 4.6 SOHC Vacuum leak (SOLVED) in forum Tech Talk at Northern California Ford Owners  .


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Posted by jg95z28 (Member # 3175) on :
 
My kid's 96 GT has a Vortech Supercharger. This morning he calls me and says his making a strange noice and it sounds like its coming from under the blower. (Not true... see below) He held up the cell phone and it is was a definite whistling noise.

My first guess was "vacuum leak" so I told him to look for a loose hose or something. However I'm at a loss with these modern day superchargers. It has been burning oil lately and the last mechanic that looked at it says there's a slight leak somewhere, but he couldn't find it.

Would low oil do this, or was I on track with the loose hose idea?

Does anyone know a could Ford mechanic that works on Supercharged cars near Walnut Creek? I don't trust Walnut Creek Ford, and Melrose Ford in Oakland said they couldn't do anything because it has a chip.

[ September 02, 2003, 10:13 AM: Message edited by: jg95z28 ]
 
Posted by cegan (Member # 3185) on :
 
Contact Apexmotorsports 408-562-1000, and speak with Bill or Vince, they are located in San Jose, they are the best in the Bayarea.
 
Posted by JohnB (Member # 969) on :
 
First, check to ensure the discharge tube (on the back of the head unit) hasn't come off. This is generally where the problem will lie if it's making alot of noise. Secondly, if it's burning (or losing) alot of oil, check both of the oil line fittings (supply and return). Normally, the feed line will come loose, and excessive oil consumption is the norm. The return line feeds into the oil pan (front of the oil pan, below the harmonic balancer). This is normally only a hose, they wear out and become brittle quite easily. If the hose is questionable, replace it and the clamps.
If you still want someone to look at it and don't want to drive to SJ, I'm in Fairfield. PM me if you're interested.
 
Posted by jg95z28 (Member # 3175) on :
 
Thanks, It sounds like the discharge tube is more than likely the problem. If he can't figure it out, is it safe to drive it home (about 2 miles) or should I leave work early and bail him out?

This kid is driving me nuts with his cars. He's 17, this is car #3 and he says he wants a hot rod he can work on, but he doesn't have time for me to teach him or a real desire to learn. (It's pissing me off because its taking time away from my own project car each time I work on it.)

I'm seriously considering buying him a Honda to teach him a lesson. [Razz]
 
Posted by JohnB (Member # 969) on :
 
It *should* be ok to drive, but have him at least look at it. That, and ensure the oil level in the engine is full.
 
Posted by jg95z28 (Member # 3175) on :
 
Thanks again.
 
Posted by 5LVENOM (Member # 2282) on :
 
Bypass valve maybe? I've blown mine off before. Just an easy check.
 
Posted by cheap (Member # 858) on :
 
17? shit.

Make him wait a week before you fix it for him, might help with the 'desire' to learn. The Honda might be a little drastic, though.

I wish my parents bought me a SC when I was a kid. [Frown]
 
Posted by section525 (Member # 2819) on :
 
Do you want another kid? I'm available. 24, in school, just need a SC for my 5.0, [Big Grin]
 
Posted by jg95z28 (Member # 3175) on :
 
Where's the bypass valve?

It definitely sounds like a vacuum leak. Its not coming from the blower but from around the throttle-body. Its stumbling like its a vacuum leak, but a can't seem to figure out where its coming from.
 
Posted by Cobra5.0Jeep (Member # 1482) on :
 
bypass valve is after the SC outlet. If its stumbling then i doubt thats is whats wrong. It must be a vacuum leak. He could have throw it in boost and it could have popped a vaccum line easily if it was a little loose.

Sorry that he won't learn sounds a lot like my brother except my brother doesn't wanna learn but we make him help fix his Bronco.

[ August 28, 2003, 05:23 PM: Message edited by: Cobra5.0Jeep ]
 
Posted by jg95z28 (Member # 3175) on :
 
Would the Idle Air Control Valve make that noise if it went out?

It sounds like its coming from near where the hose comes into the IAC Valve.
 
Posted by jg95z28 (Member # 3175) on :
 
All the hoses seem tight, with the exception of the hose going into the IAC valve which could stand to be a little tighter.

The "whistle" is definitely coming from that general area. I thought it might be the PCV valve on the passenger side or the line running from it to the intake, but that appears to be ok.

The inlet hose to the IAC valve runs through a black block near the IAC... that's just a filter, correct? (Sorry for all the questions... I'm just a dumb "Chevy" guy [Razz] )
 
Posted by jg95z28 (Member # 3175) on :
 
One more thing... it only stumbles at idle... WOT its fine... but it still whines like a SOB.

I think it might actually be a bad IAC Valve. Anyone have any experience with these.

He said it happened all of a sudden while he was driving. Based on where he was (City street traffic), I don't think he was WOT at the time.
 
Posted by JohnB (Member # 969) on :
 
Didn't the 96's have the cheap plastic intakes? Did it ever have the recall done? If it has the original one, it's possible it cracked...
 
Posted by Cobra5.0Jeep (Member # 1482) on :
 
quote:
Originally posted by JohnB:
Didn't the 96's have the cheap plastic intakes? Did it ever have the recall done? If it has the original one, it's possible it cracked...
Yes i believe the 96 and 97s had the cheap plastic intakes.

Did you check the hose for cuts maybe the hose just dried out and split.

Do the RPMs drop pretty low? I don't understand why the blower would be whining more with vacuum leak unless the intake is plastic and is broken.

[ August 28, 2003, 08:42 PM: Message edited by: Cobra5.0Jeep ]
 
Posted by jg95z28 (Member # 3175) on :
 
My kid thought the blower was whining. After my inspection its definitely coming from around the intake near the tb and near the IAC Valve.
 
Posted by Cobra5.0Jeep (Member # 1482) on :
 
Hmm i don't know, good luck. You know its gonna be something really obvious or not so check the obvious stuff first. Inspect everything i am sure you'll find it.
 
Posted by jg95z28 (Member # 3175) on :
 
Well I've inspected everything, and I'm stumped. If I use my hands to muffle the intake hose on the IAC Valve, the noise definitely subsides. I'm scared now about all this recalled intake talk, because it very well could be coming from below the throttlebody. One of my kid's friend's dad told my kid the engine is probably toast from abuse by the blower. That's horseshit! It only has about 78K mi on it, and I'm betting at most 35K are with the supercharger.

I'm still leaning towards IAC Valve; but I'm not ruling out cracked intake if the recall work was never done. (I've only had the car since Feb.)

It goes in to the local Ford dealer on Tuesday. Let's hope those jerks don't try to screw me this time. [Frown]
 
Posted by JohnB (Member # 969) on :
 
Call the dealership first, have them run the VIN of the car. They can tell you over the phone if the recall has been done.
 
Posted by jg95z28 (Member # 3175) on :
 
Its got to get fixed though. I just sold the other Mustang I had as a back-up car and my kid needs something to drive. He's petrified about driving my Z/28, so he's been using the wife's Tahoe. I just need to get this taken care of soon (hopefully by next weekend), so I can finally work on my project car. [Razz]
 
Posted by Cobra5.0Jeep (Member # 1482) on :
 
OK well let us know what it is when you figure it out, sorry i couldn't help you i am not farmilar with 4.6 GTs only Cobras
 
Posted by jg95z28 (Member # 3175) on :
 
Freeze plug on the bottom side of the throttlebody came out. The throttlebody needs to be replaced.

More expensive than a IAC valve, but cheaper than a new engine or blower.

This kid owes me big time! [Smile]

Thanks to everyone for helping troubleshoot the problem.
 
Posted by Teddy Tiger (Member # 2473) on :
 
Shit, I've had this hiss coming from my TB for the last couple of months...maybe it's the freeze plug? It idles pretty good, albeit a bit high...I was guessing my IAB too...

Nick
 




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