Too much suction in motor?

[STUDBOYZ]

What would cause alot of suction in the motor? Ive been getting a wierd whistle and when i take off the oil fill cap it stops instantly. Ive checked all the vaccume lines, retorked the intake down, the only thing i haven't done is pull the intake and reseal it. The motor runs great, idles perfect just has this whine when the cap is on??? There's so much suction that it will hold the oil cap to the valve cover then it falls off when you turn her off.

No real big mods, cat delete, headers, comp coupe cam, ecm and a roe tb.

 

[Prof]

Strange...most of us have too much pressure in the drivers side valve cover...due to the rotation direction of the engine. Have you checked your pcv valve to see if it is clogged? Do you still have the pcv?

 

[STUDBOYZ]

I dont think I do where is it at?

 

[Prof]

Under the intake...not fun to get to...

Someone with more knowledge than me will chime in soon...you might want to contact Stinker...pm him with your issue...he is very happy to do diagnosis via the internet!

 

[eddie102870]

i was thinking same thing. call justin for a catch can.

 

[STUDBOYZ]

might have to do a catch can then or vent the oil cap...

 

[TNVIPER]

Many years ago i knew a girl that made a whistling sound..

 

[Ironhead]

What would cause alot of suction in the motor? Ive been getting a wierd whistle and when i take off the oil fill cap it stops instantly. Ive checked all the vaccume lines, retorked the intake down, the only thing i haven't done is pull the intake and reseal it. The motor runs great, idles perfect just has this whine when the cap is on??? There's so much suction that it will hold the oil cap to the valve cover then it falls off when you turn her off..

i knew a girl in high school that had the same problem

 

[FerrariTruck]

crank case valve (pcv) is faulty.

 

[STUDBOYZ]

I DONT EVEN THINK ITS ON THE TRUCK.. ISN'T IT RIGHT BEHIND THE T.B.???

 

[includemeout]

Disconect Mickey from the tailpipe Ol Stretch is known for sucking sounds:marchmellow: :marchmellow: :marchmellow:

 

[Prof]

Try a Roe Breather to replace your oil fill cap...most of us have gone to it for bling...but it is vented and should address your issue...still strange that you have vacuum rather than pressure...hmmm...

http://www.roeracing.com/ProductCart/pc/viewPrd.asp?idcategory=0&idproduct=244

 

[59caddyhog]

Sounds like a blown intake manifold gasket to me.

The exact same thing happened to me with a Ford Essex 3.0 V6 back in the 80's.
It was whistling through the oil cap too.

 

[Prof]

That is an interesting diagnosis...certainly could be!

 

[FerrariTruck]

Sounds like a blown intake manifold gasket to me.

The exact same thing happened to me with a Ford Essex 3.0 V6 back in the 80's.
It was whistling through the oil cap too.

I highly doubt it. That symptom would apply if the intake manifold were made of composite plastic with o-ring type gaskets. However you are on the right track.

At this point i am still leaning at a mechanically obsructed pcv valve or one that has ruptured the rubber diaphram. A small rupture combined with vacuum generated by the motor will cause a high fequency vibration that sounds like a whistle.

I do not have my truck at the moment so I cant even go out and look to see where it is.

 

[Prof]

But why a vacuum in the valve cover????

Could it be a valve stuck open some how?

 

[FerrariTruck]

but I guess you can check the integrity of the intake manifold gaskets.

I normally use a can of brake and spraydown around the base of the intake manifold. If there is a leak, the engine will suck the brakecleener in and you will hear a rise in engine speed.

Spray liberally but just dont get it on painted surfaces as it might discolor them.

the only type of brake cleener i would use is this one because it works very well for this type of diag but is very mild compared to the others and doesnt leave a residue

http://cgi.ebay.com/Generic-Brake-C...0?hash=item254ebf3c55&_trksid=p3286.m20.l1116

avail at all your local auto parts in red or green can

 

[Ironhead]

you can also user a can of fast start ,,,easier on painted surfaces

 

[JTS VENOM PERFORMANCE]

follow some of the advice given earlier, check for vaccum leaks, bu tcheck right at the throttle body where the breather tube comes off the side to the air box, alot of times the hose can crack comming from the idle solonoid.

but as far as catch cans? ehh, I like the cheap ol evacuation system , pulls a negative vaccum on the engine giveing it more hp, and keeping the oil and gases from going back in the engine, instead it gets sucked back out the tail pipe

 

[FerrariTruck]

But why a vacuum in the valve cover????

Could it be a valve stuck open some how?

The pcv valve is meant to place the crank case under a vacuum to recover unburnt gasses per emissions reasons. Crankcase breathers are not legal under todays pollution standards.

In perf applications though you dont want to induce these fumes as they will hinder performance so they are vented to atmosphere