It sounds like you have a vacuum leak somewhere. I don't think cleaning the idle screw will since you screwed it all the way in with no change. Have you tried spraying carb cleaner around the intake with the engine idling? this is the easiest way to get a general idea of where its leaking from. Just listen for the idle to change once the cleaner is sprayed towards the leak. Once you have an idea of where it is, the pressure test with soapy water will find it in no time.

 

Thanks for your reply, Dude! Yes, I agree it's a vacuum leak. I thought it might be something in the AAS passage blocking the screw from going fully closed... don't know yet. Everything in the vacuum volume of the intake path has been checked downstream of the throttle butterflies, to and including the UIM-to-LIM manifold gasket. New gaskets between throttle body and UIM, UIM-to-LIM, under IAC valve, and under the block-off plate for the AWS valve, as well as all hose connections to the UIM leading to the solenoid rack, the PCV valve, and others. So if it isn't that the screw was faking me out when I thought it was closed, the leak has to be the LIM-to-housing gasket, which was replaced by a Mazda dealer long ago. I realize I'm looking under the street lamp for a problem that is probably in the dark; I'm just reporting as I go along.

 

It's not aways gaskets that leak, the injectors can have leaks around them too. Or vacuum hoses. Thats why its best to pinpoint at least the area of the leak. Saves time and money. Its no fun going in and replacing random gaskets just to find your problem is still there. The method i listed below should give you a general area of the leak in 3 mins or less, and pinpoint the leak in about 20 mins time. There is really no reason to do things the hard way unless working on the car is more fun then fixing it. Thanks for keeping us posted. I Hope cleaning the screw worked, sucks you have no keys to test it.

 

Yep, I know... don't even want to think about fuel injector O-ring leaks; I replaced those when I had to replace the FPD; used silicone grease on them to keep from damaging them when installing. I have no reason to think they are leaking, and with the UIM and solenoid rack on, no way to spray anything near them. Vacuum lines I have already tested, as I indicated above. I'll test/adjust the idle tomorrow, then I'll know if that was a problem.

 

Sounds like your BIGGEST problem is that it is somehow possible for your wife to take ALL of your FD keys!!! How can that happen??? Good luck finding the problem.

 

LOL! Um, it's her car... and one of the keys got tweaked somehow, so she had the spare in her purse and forgot to leave it with me.

BTW, the AAS was not the problem... idle is still at 1300 - 1400 rpm warm with screw fully CW. And now I know it is really fully closed.

 

I told you a year ago to pressure test for air/vacuum leaks and you still haven't listened. Why are people so stubborn about this?

 

The recommendations involved equipment that I do not have and have no idea how to make or buy. I have a tire air compressor and a MityVac, period. I have no idea how to pressurize the entire volume of the throttle body, UIM, LIM, turbo compressors, and rotor chambers simultaneously. If you have a link to a step-by-step for a DIY'er, or can recommend a shop in the So. CA. area where I can have that done, I will do that.

 

Hi wstrohm,

Did you figure out this issue yet? Any ideas? I have a similar problem and am wondering what I should be looking for. I'll go by all of the suggestions posted in this thread in the meantime.

 

daem0n,

Nope, haven't had time to do anything yet... still living with the high idle. My best guess at this point is that my LIM-to-housing manifold gasket is leaking air into the rotor chamber(s). Changing that gasket requires more than what I am willing to do at the moment. If I finally decide to bite that bullet and tear into the engine, I will update this thread.

 

Stop just arbitrarily replacing parts, it's a waste of time. The required equipment is so easy to make, and cheap to purchase if you're either retarded or don't own a drill. It drives me nuts watching people struggle with something for no good reason! If your idle is high it's not some major mystery of the universe! You're getting air in somewhere other then your throttle body! or the throttle body is adjusted to let too much air in! It's that simple. 2 very simple ways of pinpointing exactly where the air is getting in is (1) go buy a $1 can of carb cleaner and spray around until you find an area where the idle changes. And (2) pressure test the intake manifold and get some soapy water handy. Here are some links to make your life even simpler. It took me 20 secs to find these. (google search "boost pipe pressure tester") The next post I want to see in this thread is "I followed that simple advice and found the leak in less then a minute!"

Make your own: http://www.stealth316.com/2-pressuretester.htm
http://www.audizine.com/forum/showthread.php?t=190404

BUY your own :

http://cgi.ebay.com/ebaymotors/TURBO...61210004r26724

 

I have never done that in my entire life. Does not appear so to me; none of the referenced links refer to anything made for an FD, and all seem to require a tank-type air compressor to generate enough volume to pressurize the FD's entire intake system.I guess you really meant "unless you're either retarded or don't own a drill." Anyway, the e-bay link is irrelevant to my issue.No kidding! Well, the throttle body is completely closed to all normal entry paths for intake air. Butterflies, IAC valve, AWS valve (blocked off) and AAS are all closed. All solenoid hoses into manifold and the PCV valve hose have been checked with the vacuum mode of my MityVac.Unneccesary above the engine since I have done all the mentioned checks, and not possible on the passenger side of the engine below the level of the UIM, due to all the stuff in the way of the intake manifold. Plus, I'm not enthusiastic about spraying a flammable substance in the area of the turbos and the exhaust manifold while the engine is running, and removing anything in those areas prohibits the engine from running at all. This is NOT a simple problem, or I would have found it already and fixed it.

 

It IS a simple problem you just haven't followed the advice of others. I had a vac leak at my secondary injectors. Guess how I found it? With the advice I and others have posted many times. I also fixed one at my boost pipe about a week ago using the pressure testing method. Took about a minute.

You do NOT need a specific tester for an FD, the concept is exactly the same. Since the problem is after the throttle body all you need is something, ANYTHING to plug the end of the throttle body elbow with a fitting to put air in there. I prefer a tire valve. If you don't have an air compressor maybe you have a friend or gas station with one.

The equipment is very, very basic and common sense. Take a plastic or metal fitting, shove it into a coupler, drill a hole, put a tire valve in and stick the thing on the end of the plastic elbow and tighten it down like an intercooler pipe. Fill up with air, and listen.

And I meant it how I wrote it, basically if your retarded maybe making the thing isn't for you, or if you don't own a drill. because you will need one of those, and a drill bit. So there is the option of purchasing one. The one on ebay will work, but you will have to push the 2.5" coupling over the 2.75" elbow. I'm sure if you spend 5 mins you could find a 2.75" one with a tire valve fitting instead of the direct air coupler.

I'm sorry but there is no reason to go a year with the same simple problem and still not know the source of the air leak, especially after the solution is repeated to you. The time it spent you to get the idle adjustment screw out and cleaned you could have made 10 of those testers and figured out where the real leak is.

Use a straw that's taped to the carb cleaner can, and don't spray the exhaust. Do it when it's first started when everything is cool. A little common sense goes a long way when working on cars.

EDIT: oh wait, what does it say on that ebay link?? "* I now have ALL sizes available for any turbo inlet: 2.0", 2.25", 2.5", 2.75" & 3.0" !!"
Holly sh*T he has one that fits, now there is no need for a 5 min search.

 

You need to pressure check the motor. I just made a quick and easy setup for less than $10. You need qty 2 2" pvc plugs from Home Depot and one press in rubber valve stem from your favorite parts store.
Drill a hole small enough in one of the caps so the valve stem presses in. Remove airbox and leave the top relief valve hooked up to the y-pipe. Put one 2" cap in each turbo inlet tube and use existing clamps to hold them in. Supply air from some sort of compressor, doesnt need to be really big but if it's loud find some way to quiet it down so you can hear the air.
I almost guarantee it's a lower intake gasket. Have someone pressurize the fitting and stick your hand right underneath the airpump and you'll feel air blowing out at you. You shouldnt hear or feel any air and your boost gauge should rise and hold if you have no leaks. I just took delivery of my first FD yesterday. It had a high idle when I bought it. I have never touched an FD before today but it took all of 2hrs to find the problem. No brag just trying to give you an idea how easy the process really is. Post back with questions or problems.
I'm starting my LIM replacement today.

 

Please tell me exactly how you found it. OK, you had a spray can of carb cleaner. What, you started the engine, and somehow managed to isolate the secondary injector with the engine running? On MY FD, the secondary, and primary, injectors, are completely buried behind wire harnesses, which are buried behind the rat's nest, which is buried underneath the UIM. Not only would I NOT be able to thread a long tube from a spray can under all that mess, even if I did, I would never know what was leaking, even if I heard the engine begin running differently.Fine, but as you know, my problem is not before the throttle body, so no point in testing anything prior to it.When it's first started, it runs on its fast idle cam, and is already idling at or above the too-fast warm idle speed. That test condition will not allow detecting anything. Plus, you must be kidding about "don't spray the exhaust." It's not just the exhaust, it's the entire lower section of the passenger side of the engine that is VERY hot. The LIM and turbo/exhaust manifolds are intimately intertwined... impossible to spray selectively in that area. I would think the pressure system would be the way to go to detect a leak, IF I had access to an air compressor other than my wimpy tire compressor and MityVac, neither of which would do the job.Well written, but I don't have an air compressorl I also, at this point in my troubleshooting, would "almost guarantee it's a lower intake gasket." What that means is that no matter where air would blow out from the passenger side of the engine during a pressure test, whether under the air pump or anywhere else, I would have to tear out all the components on the passenger side of the engine, including the turbos, to get to it. And that is the same thing I would have to do if I did NOT pressure test. In short, I do not think that a pressure test would alter anything I would need to do from this point forward. So far (for the past three years) we have been living with the issue, since it is not damaging to the engine. Maybe one of these days I will decide that reducing the idle speed when warm is worth the misery, cost, and risk of doing the work.

 

You act like it's this huge struggle but its not. And if it's not the lower gasket then you end up doing all that work for nothing. And will still be no closer to fixing your problem. You apparently want it fixed or you wouldn't have gone to that waste of time pulling the air screw. I really don't care if you fix it or not, but for the benefit of others i'm saying it is not difficult to find your problem, your just making it harder then it should be.

 

If the LIM is leaking it is damaging to the engine. Pulling unfiltered air into the engine less than 6" from the apex seal is a bad thing. Anytime your engine is under vacuum that's whats happening. If you check it before you tear into it you might find it's something simple and save yourself some trouble. Good luck.

 

n2o4fun,

Good point; I hadn't thought of the air leak as a possible source of damage. Don't know how to "check it," though. Will consider doing the job to prevent further damage... in the near future.

 

"check it" = pressure test. Sorry, but that's the only way to find it that I know of.