Help!!!!!
03-11-2011, 01:07 PM
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Help!!!!! My wife decided she wanted a new toy. We now have a 1996 Camaro Z28 convertible with an LT1. It has a couple of issues. The most major of them being some blue smoke and a stumble during light throttle application. Once the engine is at temp and you get stuck in traffic, upon taking off there is a large cloud of light blue smoke coming from the exhaust. It also hesitates or stumbles if you are cruising at low speeds braely touching the throttle. I have read alot of post on other sites and some indicated that the intake gaskets could be suspect. Just curious if anyone else has heard of this or has any ideas. I did spray the intake down with carb cleaner and it indicated a leak. Plan on replacing the intake gaskets this weekend. Also noticed that the inside of the intake is very dirty and appears to be coated in oil.
03-18-2011, 09:06 PM
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sucking extra air = lean condition= high idle, hesitation, add in computer tring to compensate, and its probably sucking oil so yea sounds like intake is a good place to start.
03-19-2011, 06:32 PM
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i'm not that familiar with LT1's,
but with a 10+ year old motor if it has EGR I would look into that.
And you said you found an intake air leak, a.k.a. vacuum leak, so definitely start there. You simply can't have any vacuum leaks. One other source of idle problems is the idle control air valve (IAC), as they get old they quit functioning and cause low rpm low load and idle problems.
The blue smoke out the exhaust is from oil into the combustion chamber, causes can be pcv valve, and intake valve stem seals especially on a high mileage motor along with intake gaskets.
Aside from those, the only other source of oil into the combustion chamber is past the piston rings which you can kinda check by a compression test, low compression is either rings or valve seats. If you got good compression across all 8, better than 130psi, then I think chances are the oil intrusion is an easy fix, worst case is you pull the heads and get valve stem seals replaced.
the light load miss would be caused by misfire because of oil into the combustion chamber, and you should see evidence of that on the spark plugs. But the infamous optispark ignition on the LT1 can also cause that (not the blue smoke though) and will also cause the engine not to start. google or search here for optispark problems & fixes.
but with a 10+ year old motor if it has EGR I would look into that.
And you said you found an intake air leak, a.k.a. vacuum leak, so definitely start there. You simply can't have any vacuum leaks. One other source of idle problems is the idle control air valve (IAC), as they get old they quit functioning and cause low rpm low load and idle problems.
The blue smoke out the exhaust is from oil into the combustion chamber, causes can be pcv valve, and intake valve stem seals especially on a high mileage motor along with intake gaskets.
Aside from those, the only other source of oil into the combustion chamber is past the piston rings which you can kinda check by a compression test, low compression is either rings or valve seats. If you got good compression across all 8, better than 130psi, then I think chances are the oil intrusion is an easy fix, worst case is you pull the heads and get valve stem seals replaced.
the light load miss would be caused by misfire because of oil into the combustion chamber, and you should see evidence of that on the spark plugs. But the infamous optispark ignition on the LT1 can also cause that (not the blue smoke though) and will also cause the engine not to start. google or search here for optispark problems & fixes.
