ok so im replacing the intake manifold gasket to try and eliminate the possibility for it being a source of vac leak, i have several questions

1. here is a picture of my gasket
http://static.summitracing.com/globa...el-ms93317.jpg

those blocked ports are in the very rear of the engine, look like coolant passages, I have TBI, and those ports are open on the manifold, so i was thinking "why are they blocked?" but the old gasket was open, and had restrictor plates with a little hole in them, this new gasket has them closed but there is also a hole in them like similar to the old restrictor plates... so im going to leave out the old gasket and restrictor plates and just put this gasket in, shouldnt be a problem if i dont put the old restrictor plates back in since this gasket will do the same thing right?

2. my set only came with the two head-manifold gaskets, and not a gasket for the china wall, just a tube of RTV... so i made a seal on the china walls with a bead of RTV.. my question is, can i get a vac leak from that RTV seal being bad? or is that just to keep junk out of the lifter valley?

i am hoping that i cant get a vac leak from the liftervalley being open... thanks guys!!!

 

You get a vacuum leak from the intake charge sucking air in anywhere other than through the throttle body. There's no intake port on the china walls. Just an oil leak.

Did you even hook up a vac gauge? I think you may be chasing your tail on this one.

 

ok good i dint think there was a leak possibility on teh china wall, just oil like you said. so the only way to get a vac leak under the intake manifold is if the gasket has a crack/hole in it right?

 

Or if its not torqued properly. Might want to check and see if the mating surfaces on the head and manifold are flat also. It does seem like your chasing your tail thou. If you arent sure theres a vacuum leak there i wouldnt mess with it.

 

yeah, well the deed has already been done, i was thinking that the high idle was either due to a vac leak or something to do with vac, so i was looking at the map sensor and any gaskets that i havent replaced that might be leaking vac, since sensors probably dont go out that easily, i figured maybe i should chck the intake manifold gasket, cause ive heard people mention that when diagnosing vac leaks...

i decided i might as well check it out, learn from taking it apart, and possibly fix a vac leak by replacing the 20$ gasket instead of buying a 45$ vac gauge just to tell me if i have vac issues or not... so thats why i replaced the intake manifold gasket... more of a learning experience.

so now im just going to put everything back together and reset the timing and get it to running condition, and see if the high idle is still there. if not ill assume that the intake manifold gasket was damaged, if the high idle is still there ill use a vac gauge to measure the vac at idle and report that number here for you guys.

 

ok so everything is back together.... i got a vac gauge and it gave me a reading of 19hg at the rear manifold port and the PCV valve port on the TBI so i guessi dont have a vac leak at all/anymore

the hissing noise is still there at startup, it seems to fade away after the engine warms up and the idle loweres down to 1100rpm

i pulled the vac line off of the back of the TBI that goes to the MAP sensor, the engine lurched and started gurgling or something then i look up and theres white smoke everywhere, pouring out from under the car, so i shut it off immediately and let the fan run and blow the smoke out of the garage... it started up fine afterwards no smoke with the hose connected...

is that normal? does that sounds like something th MAP would do if it lost vacuum?

the timing was set to 4* BTDC

i duno, im thinking about maybe setting my idle screw, ive run out of ideas of things it could be causing the high idle and hard start sometimes...

im going to let it sit overnight and try starting it tomarrow morning when its cold, see if it still has a hard starting problem. thanks guys..

 

i guess ill go home and fill up the coolant and see if it runs ok..

should the car react with bogging and smoke if you pull the MAP hose out?

car still idles high with vac of 19Hg... what else could cause the high idle?

EGR? MAP Sensor?