WizardBlack Posted October 28, 2007 Share Posted October 28, 2007 I have been looking at eliminating my BCDD and running a vac line from the intake manifold to the dizzy but it won't idle down. It runs about 1400+ rpm at idle and the idle screw on the throttle body is fully closed. As soon as I route that vac line through the BCDD it drops down. Any ideas? I capped both vac ports on the BCDD when I bypassed it. Am I missing something? I would expect it to not work right. Additionally, I have the valve cover and crankcase vents open to air with K&N filters and plugged the respective ports on the intake pipe and intake manifold. It now seems to let the revs hang really bad when driving between shifts. I have used brake parts cleaner on different areas and it seems to have no leaks I could detect. Quote Link to comment Share on other sites More sharing options...
aarang Posted October 30, 2007 Share Posted October 30, 2007 If you are using a ZX dizzy, you can't put it to manifold vacuum. It needs a ported vacuum source. Plug the vacuum line into one of the ports on the bottom of the T/B and see if that helps. Quote Link to comment Share on other sites More sharing options...
spacecase70 Posted October 30, 2007 Share Posted October 30, 2007 another idea is to check that your throttle body is closing all the way, and also check your idle screw on the top of the t/b Quote Link to comment Share on other sites More sharing options...
kastmaster Posted October 31, 2007 Share Posted October 31, 2007 i am agreeing with spacecase. I had a subtle idle problem that was cleared by spraying carb cleaner and brushing off small excess carbon that was accumlating on the butterfly valve of the throttle body. It was preventing the car from dropping to the proper idle. Just my two pennies. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted November 1, 2007 Author Share Posted November 1, 2007 OK. I don't know if this has a ZX dizzy or not. I will look into a few things and dig up some comparo pics. I am hoping that the BCDD can be deleted and that that will require a blockoff plate where it bolts to the TB. Maybe there are some issues with that. The air temp related idle circuit could be stuck too, I suppose. Quote Link to comment Share on other sites More sharing options...
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