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My 3.0 swap is almost complete and back on the street. I have learned I would do the hybrid next time, it would be a lot less work, and no doubt make more power, but that is coulda woulda shoulda...my question concerns the vacuum line hook up. Last night I tried to get the car to start with no throttle application, like a normal start. The car won�t idle, and gives a pop back through the intake every now and then when cranking. I did a double check on vacuum line routings. I have the 2.5 valve covers on, each of them has a vent line that is connected up to the flex boot between the MAF and the throttle butterfly. On the 2.5 and 3.0 the evap system connected to the fitting just after the throttle, so my engine is connected up the same way. The 2.5 had what looked like a PCV valve on a tee that also connected up to the evap system. I took this off and plugged the line, because the 3.0 did not have one. The 3.0 IAC and EGR lines were connected to the intake on the back side, very near the throttle. I mixed and matched a few connectors from the 2.5 and 3.0 and have all the little lines connected up what looks right. It appears all lines are getting full manifold vacuum except the one that goes from the IAC to the EGR, it is switched by the IAC. That leaves me with the power brake line still not connected anywhere. Is there a third vacuum fitting on the intake I am missing? Any other ideas what could be keeping it from starting up at an idle setting? I don�t have linkage on yet, do I need to set the throttle position with the adjustment screw to compensate? Any and all ideas appreciated.


1999 Green Contour SVT 3.0 1999 Black Corvette 6 Speed (FOR SALE) 2000 GTP Pace Car 1993 Lumina Z-34 (SOLD!!!!) 2000 Blazer ZR/2 (FOR SALE) 1993 Eagle Talon (my baby) 1970 Camaro, since 1974 Yeah, I need more cars!
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You know what, I'm having a hard time concentrating. Next time use small paragraphs between each point or question.

As far as backfiring, make sure your plug wires are on correctly and firing order is correct.



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Wow, tech advice AND English!

Thanks!

I appreciate your help.

The plugs are connected properly.

It revs fine at higher RPM.

My basic question is where are the vacuum connections on the 3.0 intake manifold?

Specificaly, where does the power brake booster connect?

Hope this is easier for you to keep up with!


1999 Green Contour SVT 3.0 1999 Black Corvette 6 Speed (FOR SALE) 2000 GTP Pace Car 1993 Lumina Z-34 (SOLD!!!!) 2000 Blazer ZR/2 (FOR SALE) 1993 Eagle Talon (my baby) 1970 Camaro, since 1974 Yeah, I need more cars!
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Get some vac pressure on the evap system regardless.


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Originally posted by green1999csvt:
That leaves me with the power brake line still not connected anywhere.




Sticky
PIcs of modified vac

The brake booster goes to one of the intake manifold ports under the UIM. You cut the plastic at the brake booster and find the correct diameter rubber hose to clamp to that and run it to the UIM.


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Originally posted by green1999csvt:
The 2.5 had what looked like a PCV valve on a tee that also connected up to the evap system. I took this off and plugged the line, because the 3.0 did not have one.




3.0 have the PCV valve FIXED ON THE OUTLET of the oil seperator from the block. If you look on a Taurus system you will not see what appears to be a PCV. I don't know whay you plugged. Little comfused there. The 3L PCV tube should just clamp up to the largest hole under the 3L just as it does on the when it's in a Taurus.


Originally posted by green1999csvt:

do I need to set the throttle position with the adjustment screw to compensate? Any and all ideas appreciated.




Do NOT mess with any set screws.


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Originally posted by todras:
Originally posted by green1999csvt:

do I need to set the throttle position with the adjustment screw to compensate? Any and all ideas appreciated.



Do NOT mess with any set screws.



Exactly as Todd says those are "stop" screws and NOT "set" screws. This is not an old school carberutor. Everything is computer controlled and adjusted.

Why did you remove the PCV valve? The 3L and 2.5L have the PCV valve located in about the same spot. You DO NOT want to remove this.
If you "plugged" the PCV end is the tube in the UIM left open then???

It sounds like you did not do a thorough job at rehooking everything back up. There are no "huge" changes to any of these lines (vacuum, PCV, EGR, etc) so it should be setup like the 2.5L was. You should not be having any trouble at all?


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Originally posted by DemonSVT:
You should not be having any trouble at all?




No [censored] I should not be having any trouble at all!!!!!

I will take a pic of the PCV and fitting tonite and post it.

The 2.5 had 2 vacuum lines on the UIM, one for the small bore stuff (IAC, EGR, Fuel Reg, etc) and the other went to the brakes. A third, below the throttle, went to the evap system and had the PCV.

The 3.0 has a dedicated fitting for the IAC, EGR, etc that was easy to hook up to the rest of the littel stuff on the 2.5. I have the one below the throttle connected to the evap, I can easily reinstall the PCV.

I think last night I found the open port up under the intake. My problem is I did not document well enough to know where the last fitting goes. I may just pull the intake off and be done with it. Anybody have a 3.0 intake they can snap a pic of the underbelly of?

Thanks for all the help!



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Originally posted by DemonSVT:
Originally posted by todras:
Originally posted by green1999csvt:

do I need to set the throttle position with the adjustment screw to compensate? Any and all ideas appreciated.



Do NOT mess with any set screws.



Exactly as Todd says those are "stop" screws and NOT "set" screws. This is not an old school carberutor. Everything is computer controlled and adjusted.

Why did you remove the PCV valve? The 3L and 2.5L have the PCV valve located in about the same spot. You DO NOT want to remove this.
If you "plugged" the PCV end is the tube in the UIM left open then???

It sounds like you did not do a thorough job at rehooking everything back up. There are no "huge" changes to any of these lines (vacuum, PCV, EGR, etc) so it should be setup like the 2.5L was. You should not be having any trouble at all?




Not if he is running the plasic manifolds.


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Plastic manifold, what the hell are you talking about? It is a 3.0 swap, not a hybrid, so of course it is plastic! I did find my problem, I had an open vacuum port on the intake. I finally got a picture from the FCO board that helped me out. The PCV I was refering to, I now also understand is built in to the oil breather on the 3.0 and so this is not required on my engine. Throttle cables are all that is left until I hit the streets! Sorry for the lack of spaces, hope this doesn't bother the ADD boys out there!



1999 Green Contour SVT 3.0 1999 Black Corvette 6 Speed (FOR SALE) 2000 GTP Pace Car 1993 Lumina Z-34 (SOLD!!!!) 2000 Blazer ZR/2 (FOR SALE) 1993 Eagle Talon (my baby) 1970 Camaro, since 1974 Yeah, I need more cars!

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