>> On my 1.9L, there is a strong suggestion that I have a leak in the >> intake manifold. This based on pinching the auxiliary air regulator hose >> when the engine is cold and not having the engine slow, as Bentley's >> says it should. Mike, I believe a good test of the air intake system is to measure the manifold vacuum you are generating. I combed the archives on this topic a while back it seems that anything over 18 in Hg is pretty good. Below 15 or so and you should really go searching for a vacuum leak. However, low manifold vacuum can also result from air bound or poorly adjusted lifters. This topic is covered in Boston Bobs article on hydraulic lifters that can be found on his website. Have you checked the bolts that secure the intake manifold to the head? Thse suckers do come loose sometimes and can cause a vacuum leak. There are also posts in the archives where folks have used rubber stoppers and compressed air to find vacuum leaks. The basic idea is that you plug up various openings with rubber stoppers, spary all potential leaks with soapy water, then pressureize the system. If you are leaking you will see bubbles forming. Of course, you can always start spraying stuff with carb cleaner and listen for a change in the rpm's indicating that the fluid got sucked into the intake system through a leak. I think you approach of completely refabbing the air plenum is a good one. I have a new gasket that goes between the throttle body and air plenum that I have been meaning to swap in. good luck, jake 82 AC Westy |
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