Please Help With Vac Leak

JerryDaugherty · Dec 13, 2005

Please Help With Vac Leak UPDATE Here R the Codes!

mods in sig. for some reason i have an intense vac leak comming from wut sounds olike the upper plenum.. on the rpm where you have the allen screws for the side that comes off you know wut im talking about? but i soaked the entire motor with every kind of fluid to try and find the leak and nothing... all hoses are brand new.. my prob was (i thought) was that on my prev intake i had 2 of the back feet broken off. (aluminum ) so i contibuted to that but when i put the new intake on that same exact sound same pitch same loaction? wtf has anyone had this problem before?

carbed87 · Dec 13, 2005

how long has the intake been on?

try re-tourquing the bolts,
mabye a bad rtv job?

ttt as well

JerryDaugherty · Dec 13, 2005

intake has been pulled on and off about 3-4 tims now looking for it... i followed the torque sequences and stages ...rtv in the front and back of intake was solid evertime. if anything i used to much.

vristang · Dec 13, 2005

The BBK tb is notorious for being loud. It does sound just like an air leak. I have a BBK and the noise has always been there.

Are you having other problems that make you think that you have a vac leak? Most likely it is just the noise from the throttle body.

DMAN302 · Dec 13, 2005

vristang said:
The BBK tb is notorious for being loud. It does sound just like an air leak. I have a BBK and the noise has always been there.

Are you having other problems that make you think that you have a vac leak? Most likely it is just the noise from the throttle body.

Many brands of aftermarket TB's will create a vac leak sound hiss..I chased one for DAYS with my PP TB...the BBK version I had created a much less confussing sound, a whistle, however much more annoying.

jrichker · Dec 13, 2005

Occasionally the vacuum plumbing on Explorer/GT40 upper manifolds conflict with the rocker covers. This makes a vacuum leak that you can't get rid of. The vacuum lines are large enough that they sit on top of the stock rocker covers and bind. Some guys have busted the ears off the upper manifold trying to tighten them down because of the binding.

I do not know if the vacuum plumbing on the Edelbrock manifold is anything like the Explorer/GT40, but check the vacuum plubing and fittings for clearance and leaks. You may have to remove the upper manifold to get a good look at things.

HISSIN50 · Dec 13, 2005

One can try:

remove and carefully plug all vac lines going to the intake (I mean them all). Get the TB butterfly closed all the way. Put a vac gauge on one of the intake fittings/bungs. Disable the ignition and fuel system. Crank the motor. You should read some vac on your gauge (maybe 2-8" hg). If you dont see any reading, that suggests a leak.

JerryDaugherty · Dec 13, 2005

the sound im hearing is an intense whistle almost like a screama tea pot lets out... not quite that loud but almost. the leak is noticable while driving in my car with windows rolled up... and my car is NOT quiet. wuts more is that for about 15-30 seconds after start up... it idles fine and there is no sound... then all the sudden it starts to whistle and then the idle goes irratic and the car dies.

JerryDaugherty · Dec 13, 2005

also i have had this TB for about a year now and it never made this type of noise.

JerryDaugherty · Dec 14, 2005

vristang · Dec 14, 2005

JerryDaugherty said:
the sound im hearing is an intense whistle almost like a screama tea pot lets out... not quite that loud but almost. the leak is noticable while driving in my car with windows rolled up... and my car is NOT quiet. wuts more is that for about 15-30 seconds after start up... it idles fine and there is no sound... then all the sudden it starts to whistle and then the idle goes irratic and the car dies.

Sounds like you have a problem when coming out of open loop. The next step would be to pull the codes. Once you get the trouble codes from the computer others will be better able to help you than I can. I can look them up easy enough, but don't have much experience with trouble shooting.

Good luck dude.
:Word:

JerryDaugherty · Dec 16, 2005

i dont have a code reader... im starting to think that it may not even be a vac leak considering i have replaced EVERYTHING : PCV, all hoses to and from intake, gaskets fron the the heads up. Is that all? Also like I was saying the car comes up and starts very good and idles for about 15-20 seconds ( you can time it precisely witha stop watch everytime) and then it starts to whistle and then tries to die. Say I let it run till it starts whining.... drive down the block... then come back and shut it off while its whining. Start it back up and then it idles perfectly again for another 15-20 seconds. Because I am all out of ideas I have one more theory... I have a non H.O motor with crane 2030 cam... but I have a 1992 H.O gt computer and injector harness. Could this have any relevance? Is there any function the computer has that would after 20 sec. throw it into this type of condition? Also if this helps I have no EGR completely removed (I think) and a block plate installed. When removing the EGR equipment... Wut all is there? Im asking alot of questions because I dont have a computer right now so I can only check this like 2-3 times a day if Im lucky. And some of these questions may be totally irrelevant to wuts going on but IM COMPLETELY OUTA IDEAS HERE. Besides renting any diagnostic tools I refuse to put anymore money into the car... So if it doesnt get figured out in the next week or so the cars gotta go. Tired of riding the damned bus!

jrichker · Dec 16, 2005

You don't need a code reader, all you need is a paper clip...

Dump the codes and see what the computer says is wrong…

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Walmart.

Or for a nicer scanner see http://www.midwayautosupply.com/detailedproductdescription.asp?3829 – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $35.

JerryDaugherty · Dec 18, 2005

well when i put my white face cobra gauges on my 92 i just pasted them on over the regular ones so you cant see any lights other than the tach and speedo and such the chk engine light is barely noticable in the dark. but off the top of anyones head is there anyhting the comnputer can controll comming outa open loop that would send my motor into this mess? I will be picking up a code reader after work tommarrow. when it gives me a code is there a site i can translate them on?

jrichker · Dec 18, 2005

Post you codes here and you will get some help.

JerryDaugherty · Dec 18, 2005

aight man thanks i will prolly go get one tonight

BlackGT89 · Dec 19, 2005

A lot of good suggestions above. Since you aren't sure of the source of the sound, I would suggest using a stethoscope (I use a spare heater hose) to pin point where the sound is coming from (be sure and check under the intake). If you are not sure if it is a vacuum leak, you might try removing the belt and start the car without any pulleys / accesories turning and see if the eliminates the sound (without overheating the engine of course). While you have the belt off turn each pulley by hand to see if any of them are dragging. Check the water pump shaft for wobble and excessive wear. Might even suspect the alternator. Just throwing out some suggestions, good luck.

JerryDaugherty · Dec 19, 2005

ive pin pointed the sound to the side cover of the upper intake manifold but i have taken it off and put new gasket and rtv the **** outa it to no avail... i can almost swear it is comming outa the side cover but i have sprayed it with every fluid and doesnt change the idle. how many vac lines come off the intake and where do they go to? I have one to the FPR one to the VAC tree and one to the PCV and then one is just blocked off.. is there anyone im missing?

jrichker · Dec 19, 2005

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring and lots more…
http://www.veryuseful.com/mustang/tech/engine/

Diagram courtesy of Tmoss and Stang&2birds.

HISSIN50 · Dec 19, 2005

If you think the leak is coming from the manifold, try my above-suggestion if you feel like it.

Good luck.

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