Join Date: Sep 2002
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Re: vacuum advance question
I am going to play a bit and see what happens. I am currently running ported vacuum for the vacuum advance and my theory is that when the throttle plate cracks open the vacuum advance get the signal to advance before the motor can even respond. I have been told to try playing with the vacuum on port and manifold and the engine will tell me what it wants.
I can move to the next topic of EGR and vacuum. The 1986 258 uses a EGR that needs vacuum signal and exhaust pressure
to open. I have installed too EGR valves and can make the valve open on the test bench by blowing into the EGR port and using a vacuum pump. I can wind the motor to the moon and use a vacuum pump as the source and the EGR will not open. I am not running a cat becuase it clogged and all the pulse air stuff rotted off. Can the lack of back pressure from the lack of a cat be causing the problem?