First off, thanks in advance for any help I get and YES I did use the search forum but had no luck.
Just completed a total engine rebuild on my 89GT and having a weird vacuum problem. Here is what all I did to the motor; rebuilt the short block (kept everything stock), put on GT40 heads, TFS Stage 1 cam, 24# injectors and put on a ported GT40 intake. I have a 70mm TB with a 73mm C&L mass air calibrated for 24's. I also removed the air pump, p/s and a/c. Am running a electric fan, under-drive pulleys, swapped to a 130 amp alt (which isn't charging) and did a five lug/rear disk upgrade.
Here is my problem; I only have 10in of vacuum @ idle. I have adjusted the valves 3 times, checked for vacuum leaks (don't have any that I can find), checked my timing, made sure my firing order was correct, reset the computer and all that other fun stuff. The car idles fine and seems to be responsive when I snap the throttle. Now here is the weird part, when the engine is cold and I pull a vacuum lime off it runs like crap and loses vacuum. If I do the same thing when the engine is warm the vacuum goes from 10 to 15in and the idle raises to about 1500 rpm. I have never seen anything like this before and am totally frustrated by it.
I hope I haven't confused anyone, if so let me know and I will try and explain better. Thanks....-J-
Just completed a total engine rebuild on my 89GT and having a weird vacuum problem. Here is what all I did to the motor; rebuilt the short block (kept everything stock), put on GT40 heads, TFS Stage 1 cam, 24# injectors and put on a ported GT40 intake. I have a 70mm TB with a 73mm C&L mass air calibrated for 24's. I also removed the air pump, p/s and a/c. Am running a electric fan, under-drive pulleys, swapped to a 130 amp alt (which isn't charging) and did a five lug/rear disk upgrade.
Here is my problem; I only have 10in of vacuum @ idle. I have adjusted the valves 3 times, checked for vacuum leaks (don't have any that I can find), checked my timing, made sure my firing order was correct, reset the computer and all that other fun stuff. The car idles fine and seems to be responsive when I snap the throttle. Now here is the weird part, when the engine is cold and I pull a vacuum lime off it runs like crap and loses vacuum. If I do the same thing when the engine is warm the vacuum goes from 10 to 15in and the idle raises to about 1500 rpm. I have never seen anything like this before and am totally frustrated by it.
I hope I haven't confused anyone, if so let me know and I will try and explain better. Thanks....-J-