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Discussion Starter · #1 ·
Hey guys, I'm pretty sure my intake manifold has a bad leak to the point where the care is undriveable; barely idles and ends up dying. I have replaced the block to lower intake and lower intake to upper intake gaskets 3 times now. Each time when I start her she runs great and I let her warm up and everything is fine but once I give her any throttle something goes wrong and I start experiencing the same problem (bad idle and dies). After that it doesn't matter whether the car is cold or not. I can come out to the car the next day and start her cold and get bad idle immediately.

So it seems to me there is a spot where the gasket seal is barely being made if at all and this spot is breached very easily. I was wondering if anyone else has experienced this situation and how a "shadetree mechanic" might care for the problem. Also would it be a bad idea to just run a thin strip of one of the liquid gasket sealers along the gasket to take care of any "weak spots"? Any info would be appreciated. :scratch:

Thanks

Robert
 

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are you removing all of the old gasket when you replace it? if there is some left over it could pose a problem. also has you car ever had a problem overheating? it is possible (not real likely) that one of your manifolds is slightly out of true.
 

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Discussion Starter · #3 ·
The engine has never seriously overheated but the intake has never caused me this problem until recently. I always try to make sure the intake is free of old gasket and have tried to be especially thorough because of the trouble I'm having. There are a few pit marks and scratches on the intake but they were there before and didnt cause any problems. Would it be okay to use a thin strip of liquid gasket on the regular gasket to make sure it seals all the way around?
 

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Discussion Starter · #7 ·
Ok guys, I got a compressor and built the leak tester. I pressurized the engine at about 17psi with the compressor (engine not running of course) and I found air leaking out of the engine from two of my injectors (actually the holes the injectors fit into I guess). I can press on them lightly and the leak does stop.

Now, I am sure this is a dumb question but...could this be what is causing my problems as described above? I know that air should not be leaking from the injectors but I dont know if the same physics are in place when I am forcing air into the system with an air compressor as opposed to when the engine is running. I'm guessing with the engine running if air is still being forced out past the injectors then this screws up the air/fuel mixture? Or maybe the piston chamber doesn't achieve the proper pressure for combustion because of the leak?
Bottom line; is this the what has been causing my car to sit in the garage for the last 8 months? Thanks in advance for any info.

Robert B
 

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if there is air leaking from your injectors, this is the "intake manifold leak" you described.

Can you move your injectors up and down freely? Your fuel rail is potentially not bolted down completely or else you just need new injector seals. The injector leak is basically the same as any other leak in the intake track, so fix it and you should be golden.

adam
 

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Discussion Starter · #9 ·
Well, I cannot move them up and down, but they do rotate side to side pretty easily so I'm gonna pull the fuel rail and replace the seals. Thanks. And a big time THANKS for whomever came up with the Home Depot leak tester! :rockon:

Robert B
 
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make sure your injector seals are installed correctly, if the insulator at the tip of the injector is sticking out at all, you will have a vacuum leak
 
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