so the last two days my '86 GT has been high idleing at 2000rpm in park and neutral. and in gear it would take off on its own without me pushing on the pedal, so i knew something was wrong. well after checking the iac and tps and with no visual leaks from the egr i had my local mech take a look and half a can of carb cleaner later he tells me that the lower intake gasket was bad and letting it suck air in. my question is do i just replace the lower gasket or just buy a set and have my mech replace all the intake gaskets? and do you guys suggest driving it other than to his shop till then?

thanks

I would also check youe EGR tube that goes from the
EGR valve to the upper plenum for cracks. A very common
vacume leak that will cause high idle.

If you have a lower intake gasket leak, you will need to
replace it and is the same as rebuilding the top end of the
engine. Gasket set for TB, Intake manifolds, O rings for
fuel injectors and other things. If you need to do this, also
consider that it's a good time to repaint the plenum, valve
covers, replace sensors / connectors, check other vacume
lines, etc.

You'll be fine getting it to his shop. Do them all, what have you got lose? I ran for 2 months as a daily driver with an intake gasket leak at the head and I didn't burn a valve.

[This message has been edited by Sidecar 2M6 SE (edited 06-08-2010).]

The EGR tube is right there where the lower intake is. 95% of the time what you are having is caused by a leaking EGR tube. Where your mechanic sprayed the fluid ALSO happens to be where the EGR tube is. The tube is covered with a cloth cover so it is very hard to SEE the cracks in it.

Want a 'free' fix? It's kinda difficult to get your fingers in there however its not that hard AND most likely this is the cause of your trouble. Take off the EGR tube. The bolts that hold it to the bottom of the intake are hard to get your fingers to but you can get them. After you have the tube off take a razor blade and cut the threads that hold the cloth insulation on. Peal it back and see if you have cracks. One of the fixes many do is to just disable the EGR by making a block off gasket from an aluminum can and sandwitching it inbetween the EGR tube and the bottom of the INTAKE MANIFOLD. (DON'T try to do it at the easy end of the tube instead, it's on the wrong side of the leak) (Trust me I work for BP)

Most likely this will fix your problem. You can even consider it a permant fix if you don't have to worry about emission testing. Fixing the leaks in the tube are a better fix. They CAN be braized shut and that WILL hold. There are also other ideas for the tube fix on here if you wish to look for them.

Perhaps your mechanic is right. I will say with Fiero experence it is much more likely to be an EGR tube instead of a intake gasket leak. It's also easy to mistake one for the other since they are right in the same area. The EGR tube fix is MUCH easier. If nothing else at least tell your mechanic before he pulls the intake off so HE can cut back the insulation and check to see if the tube is leaking.

ok and when my mech sprayed the carb cleaner nothing happened when he sprayed around the egr or the tube. the leak he found was over by the t stat housing and all that stuff. if that helps any. you guys have any ideas to test if it is the egr tube along with the intake gasket before i get the intake gasket replaced? besides of course checking it for leaks and or sealing it off at the manifold? all the local mech shops around where i live cant get my car in till next week.

Just to let you know, the full intake gasket set costs about $22. How much are they going to charge you to change it?

Here is a pic with the lower intake removed. Notice the bottom part of the gasket goes over the pushrods and top part goes behind them? Make sure your mechanic does not cut the gasket to accomplish this. Make sure he removes the pushrods, places the gaskets, and then replaces the pushrods (in their original order) and sets the lash correctly. It's very easy to cut corners if the owner doesn't know any better.

[This message has been edited by Hudini (edited 06-08-2010).]

If it is leaking over by the thermostat housing, then that is where it is leaking. Seems like you do need the intake gasket.

You could take the EGR tube off and inspect if if you wished. Not sure how much easier you are looking to make it beyond that. 4 bolts.

Just a quick question on the EGR for you all, what will you lose or gain by blocking it? i've had 2 of these with cracks around the flanges that hold it onto the intake and keep thinking, should I just make a blockoff for it and call it a day? Sorry I did not mean to jack the thread just wanted an idea while people were thinking about it.

Well instead of hijacking this thread why don't you just start a new one. It's quite easy you know!

all the mechs i asked about doing it want to charge $400 - $425 to do it, meaning buying the whole gasket set and replacing them all...and i was unaware of the cutting gasket shortcut. thanks for the heads up on it. the two mechs i trust with working on my car both have worked on fieros in the past, just hate them cause of working on them. but they have done the majority of the work to mine. since i dont have the time or place to work in-depth on mine. but with the gasket shortcutting the mech sounded like he wouldnt do it when i talked to him cause he said he'd have to pull off the whole top of the engine to place it so.

i had another question. i know that with the engine running if you push up on the diaphram of the egr valve it should stall out the eninge right? well i tried at as an option for the leak.. well when i tried it it didnt stall out... could that just be because of the intake gasket leak? i've done it before when the code for the egr came up and it did stall out. any comments?

leaking by the t-stat housing? this sounds like the gasket between the lower plenum & the intake manifold.

one of the tough parts when discussing the intake is what to call the parts. there are 3 mains one: the upper plenum, lower plenum & intake manifold.

Unfortunately I've had my intakes off far too many times. A couple leaks plus an experiment with a home made intake. It's not hard at all. You need some basic tools like metric sockets and wrenches. A small torque wrench is very helpful too as the intake bolts are 19 lb/ft which can be easily over-torqued.

The top chrome intake bolts are 12 point 10mm bolts. Most sockets are 6 point so that one is a little weird.

I use a 5/8" flare wrench and 17mm open end wrench on the fuel lines after soaking with PB Blaster. Not sure why the inches and millimeters are mixed here, might be I'm using the wrong sizes but it works for me.

Take pictures in case you forget where hoses are routed. Don't leave anything to chance. Go slow and use the right tool. I'd recommend a Haynes or Chiltons manual too.

yes the leak is from the lower manifold gasket. and i do have the haynes manual. do i just follow the part the covers tearing the engine apart and about the pushrods does it cover how to remove them?

Yes the manual covers on how to do it.

Page 77 - Chapter 2 Part B Section 5 - Intake Manifold - Removal and Installation

You will have to remove the rockers also since they go through the gasket.

Page 79 - Chapter 2 Part B Section 7 - Valve Lash - Adjustment - to re-install them

[This message has been edited by phonedawgz (edited 06-10-2010).]

Just a word of caution. I have found that in used engines the 1.5 turns of the rocker nut after zero lash is too much which ends up not allowing the valves to close completely. I go 3/4 turn after zero lash as many experienced Fiero mechanics go. It is a pain to have to redo the lash adjustment after you put it all together as there is alot to take apart. After valve adjustment, I do a compression check just to make sure the valves are seating.
Jim

quote Originally posted by phonedawgz: Yes the manual covers on how to do it. Page 77 - Chapter 2 Part B Section 5 - Intake Manifold - Removal and Installation You will have to remove the rockers also since they go through the gasket. Page 79 - Chapter 2 Part B Section 7 - Valve Lash - Adjustment - to re-install them

You don't need to remove the rockers. Get this tool: http://www.buy.com/prod/lis...66357/212937997.html

You may have to rotate the engine to get them all free, but you don't have to mess with the valve lash. I also used this tool when removing the heads and everything came back together perfectly.

J.

so just an update. took my fiero to my mech and after he had it back together from replacing the intake gasket. sure enough the egr tube was leaking also. doesnt it really matter it i just block it off or replace the tube?

The first reply here hit it on the head. Next time your machanic tells you something is going to cost hundreds of dollars to fix wait a lil longer and read more replies! Lower intakes gaskets seldom go bad. I've for one have never heard of it happening.

There are lot people here that know way more about these cars most 'local machanics' you'll talk to. Your local guy's diag was aweful -or he was just looking to run the bill up- I hope you didn't pay $400. There were lots of other more common reasons for vacuum leaks than the one picked: EGR, dry injector O rings, cracked plastic vacuum lines etc etc. FInd a new shop.

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I hope it wasn't the EGR tube leaking in the first place. Ouch.

Blocking the EGR is easily accomplished. If your only concern is driveability then it won't matter. Your state have smog checks?

Here is a description of one fix: https://www.fiero.nl/forum/Forum2/HTML/106052.html

my mech only charged me $160 to replace the seal and block the egr tube. anyone have any ideas on where to get a egr tube, besides the fierostore im not fond of needing $100 for a new tube.

How cracked is the EGR tube? If it's not too
bad, then some people just have it welded to
fix it. If you are going to replace it then the
braided EGR tube is the way to go. I know
the $100 from FS is alot, but this tube should
have been this way stock as the exhaust and
engine can movement independent from each other
and is why it cracks in the first place. Not sure
if there is another source/option for cheaper.

I braised mine and the fix works. I don't think it's weldable - It's too thin.