odxr

I am replacing the heater core in the bosses 99.While removing the intake manifold I noticed the vacuum line for the fuel pressure regulator connected to the duct that runs between the throttle body and the maf.Is this correct?Usually a fuel pressure regulator gets manifold vacuum.

Fast one

That line is there to vent any gas fumes to the intake, not for regulating fuel pressure.

Bill Curlee

97 & 98 C5s have a pressre regulator between the fuel rails and yes, the vacuum reference line connects to the air bridge
Its a reference source for the regulator. There is an aftermarket kit that connects it to a vacuum source on the manifold.

IT isnt a 99 if you hve a manifold mounted regulator and TWO fuel lines (SUPPLY & RETURN) OR someone made a major conversion

BC

markknorton

Wow, I'm so glad to find a resource on this. I have a California 98 vert and the previous owner put a blackwing on it and said, No problem it will pass SMOG. but No!. blackwing not cali compliant. OK off to Ebay to find parts. original airbox. so I put the factory airbox back on but left the smooth orange connection tube in place that came with the blackwing, that replaced the original air bridge bellow . Nope. SMOG dude said " not original" fail.
So back to the drawing board. I have a original Air bellow. but don't see a place to connect the fuel pressure regulator vacuum line.
Sorry about the long background to the real question. Where do I connect the vacuum line? my air bridge is 97-08 but the bellow I got off ebay is not. do I just drill and insert? does anyone have a picture of the insertion point. the bellow has a flat spot that looks like a likely place to drill and insert. pictures anyone. I looked at 8 vettes at used car lots today but all were 2000 or newer without the vacuum line pressure regulator. I'm desperate to pass smog visual inspection so want to get it right.
thanks

markknorton

any one have pictures of the insertion point of the vacuum line into air bridge or bellows?

markknorton

98 vert vacuum line upgrade kit??? mentioned above for my fuel pressure regulator
I need one. but can not find on the net.
any help appreciated

lionelhutz

The connection is just a small plastic nipple plugged into the side of the air bridge probably 1" or 2" in front of the flexible part that connects to the throttle body. But, the connection is not required because it is before the throttle body so it's not a vacuum reference - the fuel pressure on the LS1 doesn't change with vacuum like earlier vacuum referenced setups do. You could just run a hose from the regulator under the engine cover so it looks to connect somewhere instead of the port being left open.

My best guess for that connection was so that if the regulator diaphragm failed and started to leak it didn't dump fuel over the engine. But, I'm not sure that dumping it into the intake is the best choice either.

markknorton

Thanks for the reply.
there is a lot of discussion treads in forums about it being referenced on a 98. ultimately I want it to run as clean as possible. but for now I would like to see exactly how and where the stock setup is connected so I can duplicate bone stock for California SMOG inspector purposes. they have become rabid about any deviation from stock and seem to know what stock looks like. do you have a picture of a stock insertion/connection point on the air bridge for this vacuum line? and any knowledge about how it may affect the fuel mixture and in turn SMOG test outcome if it is just capped off?
thanks

markknorton

what year is your c5?

lionelhutz

It took all of about 10 seconds searching Google Images to turn up this link....

https://www.corvetteforum.com/forums...uum-lines.html