Hey, I have been getting bad gas mileage recently and I decided to pressure my intake to see if I had any boost/vacum leaks. I used my friends tester which is a plate that goes into the intake passed the maf sensor (lindsey stage 2). Well I tried to pressurise it to 5 psi and I can't even get it to go over 2psi. It is leaking under the manifold near where the two vacum lines go into the coolant switch between runners 3 and 4. Any ideas or should I bite the bullet and buy lindsey racings vacum line kit. Thanks for any help. Oh and on idle when the car is warm it is showing around 17 in hg. on my boost gauge.

 

17 is pretty good.

Have you cleaned you air filter for the bad mileage?

 

It is clean, but I can tell you that there is some type of major leak under the manifold. When it is pressurised I can feel the air coming out under the manifold.

 

Sounds like you're pressurizing the crank case via the hose that comes off the top of the air/oil separator. Unless you want to blow out all of your oil seals, be sure you have this disconnected and the port on th j-pipe capped.

 

5 psi will do that? Sorry but I am not sure how else to check this. Can I just cap off the pip coming off my maf and off the maf tube itself? Thanks.

 

I say go ahead an buy the vac line kit . I did mine this weekend all the vac lines lindsey breather tank an new intake manifold gaskets.The car runs much crisper.An the AFR gauge reads leaner so I know I fixed some leaks.

 

Thanks, that is what I think I will do.

 

You should pm MySwiss about getting one of his vaccuum line kits.They are good kits. Though that may not be your entire problem, it is bound to help if you haven't had any lines cahnged since new.

 

Just so you know it took me about 2 hours to remove the old gaskets an clean all the surfaces(not fun).I used my wet dry vac an brake clean to suck up all the mess.

 

My manifold was off not to long ago, and ehall all of my lines are original. I may pm him and see what he has. Thanks for the info. Do you think that may be my problem?

 

I used to have a leak coming from the rear of the intake, just where that valve is located.

You need to spary some soapy water to pin point the leak, mine turned out to be the gasket on #4 runner.

If that valve turned to be faulty, you can run a straight line from the fuel purge system directly to the throttle body.

 

It's very common for the plastic vac lines and t fitting to have leaks, if they have never been replaced. Did you have this problem BEFORE you took the manifold off? If not, start there first. The soapy water trick is a good one. I would replace the lines while I'm in there.

 

I am not to sure if the problem has always been there or not. This is the first time I have tried pressurizing the system and there is deffinetely a problem. I will check again this morning and then order lines or report back.

 

Ok well I got it under control a little. The car is leaking at the coolant switch with the two vacum lines running to it (its the unit not the lines). Anyway to fix that or just leave it alone? It is leaking at the idle air screw (mine does not have a cap on it). Where can I get a cap? It also seems to be leaking at the throttle body shaft a bit and the fuel purge valve up on the driver side fire wall. I don't think any of these would cause my rich condition. Is there anyway to check my fpr for sticking? Thanks.