Question : Lumina z34 3.4 vacuum leaks?

[skeletatious]

Hey guys, first time poster here. I bought a 92 Lumina Z34 about a year ago and I noticed that it revs high (2500RPM and up) for a while, until it warms up (epically when it's cold out) I also get a SES light that tells me to replace the IAC valve.

I don't know too much about cars, but it seems to me that the problem might not be the IAC valve because once the car warms up, everything is good and I never get a problem with the revs being too low. I did some research and thought that it could be the intake gasket, so I tried checking for leaks by spraying the gasket seal with quick start. But, I didn't find any. Then I saw a missing bolt under my fuel rail.


I have no idea what this bolt is for or why it's missing or if it would even make a difference. Any insight to my problem would be greatly appreciated. Thanks.

[skeletatious]

sorry about the huge resolution of the pictures. But, there's 3 different ones there from different angles.

[Weatheralls Auto]

Pics are too big to see correctly, I think the bolt holes you are seeing are the ones to install and line up the Lower Intake Manifold correctly.

Your description of problem sounds like the Lower Intake (LIM) leaking.

[skeletatious]

Yeah, sorry about the pics. Here's the link to them in a smaller res.

http://img192.imageshack.us/gal.php?g=0000640.jpg

Yeah, I think you're right though. They are just to line up the LIM correctly. Oh well, just thought it might be contributing to the problem. Tried putting fix-a-leak engine sealant in the oil. It helped for about a week. Now the car is going back to shit. Guess I might have to bite the bullet and bring the car to a mechanic, unless someone knows of a tutorial for testing and changing the UIM and LIM gaskets.

[pocket-rocket]

+1 on the LIM gaskets. Don't take it to a mechanic if you have a set of tools. It's a cake fix. Look up the timing belt walkthrough to find out how to get the UIM off, from there it's just a few more bolts. The fuel rail doesn't even have to be unhooked from the fuel lines, just unbolt the hold downs for it, pop the injectors out of the LIM and swing the fuel rail with the injectors still in it out of the way. Then its what, something like 10-12 bolts to get the LIM out? Simple job and can be done in a couple hours easy at a really relaxed rate. I did mine before I really got into turning wrenches. The most I did before that was simple stuff like brakes, alternators and water pumps.

[skeletatious]

Cool, thanks guys. Just have one more question. What else should I change while I'm doing this?

[pocket-rocket]

The distributor O ring. You can pick up a new one at the stealership for around $3. You won't be able to get the plug all the way out without removing the rear head, but many people have had success with doing it this way:

http://60degreev6.com/forum/f100/did-sparkplugs-and-oil-leak-t43995/post396593

[Weatheralls Auto]

I have done the distributor Oring many times and have NEVER had a comeback.
Lift it up and use Anerobic sealer, not RTV, squeeze some under the cap, then turn cap to spread.
It will never leak again.

Even with out an oring at all it will not leak.

[RedZMonte]

i agree, lower intake gasket leak... once it heats up the metal expands and the leak seals itself up... not hard to do, just take your time, get some felpro gaskets form the parts store and double check everything while putting back together.. the bitch part in my opinion is the coolant hose connecting the upper intake where ever that connects to. Also do a new T-stat. while apart i would also shoot the upper and lower intakes with some brake clean and clean any gunk out of the intakes. the lower intake has 2 alignment holes on it, clean the heads and intake surfaces before the new gaskets go in. once the gaskets are on, align the lower intake and use some bolts to tighten down the lower intake so that all the bolt holes line up, don't try putting the lower intake bolts in untill you have the other 2 alignment bolts in or you can cross thread the other bolts into the head.

If you can do the O-ring described above i would do it, its most likely leaking... It is a PITA. if the oil is covering your trans bolts where the grounds connect on the front top side of the trans, shoot some brake clean on them to clean the grounds...

I would do a new set of plugs, PCV valve while apart if they havnt been done recently. I would recommend running some BG MOA oil treatment (cleans out sludge in the motor). i would also do a fuel filter (5 bux) and run a can of BG 44K Fuel Inj cleaner.

I would also replace the Brake Booster hose that connects to the back of the upper intake and the brake booster. it gets squishy from the oil in the intake and you lose your brake boost. Probably the best CHEAP mod you can do.. you will be supprised how much better your brakes feel. the hose is like 5 bux from the dealer.

Have fun

S

[skeletatious]

Thanks guys, you've all been a big help.