Idle surge & cracked exhaust manifold

[LoTekGuru]

I've only had my Talon for about a month and it has pretty bad idle surge. I read somewhere on this forum that a cracked exhaust manifold can cause idle surge. My question is, is the crack I'm seeing cosmetic or is the manifold a solid piece of metal so the crack I'm seeing is most likely all the way through, and could be causing a small leak which in turn could be causing my idle surge?

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[LoTekGuru]

Well dang I wish I had thought to check on this post earlier! When I originally did a search on idle surge, none of the posts I read mentioned anything about the BISS.. I adjusted it and BAM! one constant idle again! Thanks for the info everyone, and thanks to femmeDSM for posting that link showing where the BISS is located, and the other one for proper adjustment technique. Now to find a good deal on a 2G exhaust manifold!

 

[BK85]

well i tighten it all the way then it wanted to die on me then i adjusted it till it idles at about 750-800rpm it sounds a better like it not choking as much as it was. but i tried to back the screw all the way out and it just wouldnt come out so i cant tell if the o-ring is bad or not any suggestions on how to get the screw all the way out, it just seems like there is more thread but it doesnt come out anymore

It screws out only so far, than you have to pick it out with a spring hook or a paper clip. be careful it will want to fall just as it clears the hole. Mine did and it took hours to find it. If you are still having idle problems it could be a vacuum leak somewhere. my mechanic takes carb cleaner and sprays it all over the intake system. the stuff is so flammable that if you spray it on a vacuum leak the engine will speed up. good way to check for gasket leaks.

BK85

 

[jepherz]

you screw it snug, sometimes they back out and fall out. Yours may not even be in

The purpose of the BISS screw is to adjust the base idle for your car. To do this, you have to ground a few pins and then adjust the screw to set the idle. You never just screw it all in, otherwise what would be the point in having it?

The cracks in the problem are not the cause of your idle surge. If you start the car, chances are you won't even feel anything coming out of them. This is nothing you need to WORRY about, just be on the lookout for either a 2g or evo3 manifold, as their casting materials are much better than the 1g and won't crack as easily.

Nothing to worry about.