as i asked, one if the bolts that holds header on the head is stripped. will this cause a major vacum leak??? I am having very bad idel problems and car runs like **** like its rich or something. it boggs. I just had it dyno tuned 2 weeks ago so I know fuel mixture is correct. what do you guys think?? is it just a vacum leak????
thanks in advance

 

possible. it may trick your o2 sensor in thinking/reading lean and forcing the ecu to richen the mixture. idle it should not effect much at all. that may be an entire different problem.

 

all the header does is collect the the exhaust gases it has nothing to do with vacuum.

 

also, you have like 9 other bolts or studs/nuts hold the header on so worst thing i could do is cause an exhaust leak.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by airborne84000 &raquo;</TD></TR><TR><TD CLASS="quote">as i asked, one if the bolts that holds header on the head is stripped. will this cause a major vacum leak??? I am having very bad idel problems and car runs like **** like its rich or something. it boggs. I just had it dyno tuned 2 weeks ago so I know fuel mixture is correct. what do you guys think?? is it just a vacum leak????
thanks in advance</TD></TR></TABLE>
If it has an exhaust leak there, it can also let air in which will screw up your o2 sensor voltage. (It would make it run rich.)

 

no the exhaust will leak OUT constant pressure coming out won't let air go in.

besides the other bolts on the manifold would hold it tight enough to the head you shouldn't even get the leak.

 

ok thanks guys, I just took it over to the shop today to be looked at. I'll let you know what happens

 

no it wont. Unless you only have like 3 bolts holding it on, maybe. But that is why you have a Exhaust Manifold Gasket. Also it wouldnt be a vaccum leak if it was in the exhaust. It would be an exhaust leak, and prolly would blow out instead of suck fresh air in. Check the intake side for vacuum leaks and all wiring to sensors, eg O2, map,

 

You can take out that stripped bolt, vice grips it and it will come out. I had one that was messed up too so I just replaced it, only about $1.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by foozball-26 &raquo;</TD></TR><TR><TD CLASS="quote">no the exhaust will leak OUT constant pressure coming out won't let air go in.

</TD></TR></TABLE>
Wrong. A leak in the exaust system will let air in also. If the leak is upstream of the o2 sensor, it will throw off the reading.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca &raquo;</TD></TR><TR><TD CLASS="quote">
Wrong. A leak in the exaust system will let air in also. If the leak is upstream of the o2 sensor, it will throw off the reading. </TD></TR></TABLE>

dude its common sense try blowing in a straw constantly, air is not going to be let in while you are blowing out of the straw, same goes for the exhaust manifold b/c of the constant pressure comming out of the head.

use your noodle

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by foozball-26 &raquo;</TD></TR><TR><TD CLASS="quote">

dude its common sense try blowing in a straw constantly, air is not going to be let in while you are blowing out of the straw, same goes for the exhaust manifold b/c of the constant pressure comming out of the head.

use your noodle</TD></TR></TABLE>

makes a lot more sense to me....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Foozball26 &raquo;</TD></TR><TR><TD CLASS="quote">

dude its common sense try blowing in a straw constantly, air is not going to be let in while you are blowing out of the straw, same goes for the exhaust manifold b/c of the constant pressure comming out of the head.

use your noodle</TD></TR></TABLE>
That would make sense, if it were true. but there isn't constant presure coming out of the head. It comes out in pulses. Think about it.

 

As air flows over a hole that is perpendicular to the flow, vacuum is created.

A simple example: Drag racers using the exhaust to DRAW out crankcase fumes.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca &raquo;</TD></TR><TR><TD CLASS="quote">
That would make sense, if it were true. but there isn't constant presure coming out of the head. It comes out in pulses. Think about it. </TD></TR></TABLE>

This is right..

It's the same idea with why a lot of cars use AIR systems to inject fresh air into the exhaust manifold, to prevent exhaust reversion, getting exhaust gas sucked back into the head... it confuses the O2 sensor when this happens. Injecting air with an AIR system prevents this reversion.

 

Is the new thing to run no exhaust manifold gasket??????????????

 

right it pulses look at the firing order 1-3-4-2 so there would always be a cyl. ejecting gases so it fills up the spaces in between each cyl. pulses

that theory would be true if all the cyl fired at the same time

theres still no way for air to get in though b/c he is only missing one bolt.