I've developed a vacuum leak and checked the "Vacuum and Vapor Hose Diagrams" document for routing. This doesn't show the large hose that comes off the intake plenum at the center-rear. I got under my car and traced this hose to the firewall. Can anyone tell me where this is supposed to go and what its function is?

Thanks.

Eric

On the donor car this hose was for the power brakes. Depending on the install, it might be connected to the brake booster or it could be connected to any number of other things.

Can you trace it any further than the fire wall? With the engine running disconnect the vacuum hose at the brake booster to make sure you have vacuum there. Then with it still disconnected disconnect the line at the intake. If it is going to the brake booster you will lose suction when you disconnect it from the intake.

Thanks FieroRenke. I can't run the car right now because I have the plenum off to re-route some of the wiring. When I've got it back together I'll block off that tap on the plenum and see if that cures the vacuum leak.

Eric

quote Originally posted by eajohnso: I've developed a vacuum leak and checked the "Vacuum and Vapor Hose Diagrams" document for routing. This doesn't show the large hose that comes off the intake plenum at the center-rear. I got under my car and traced this hose to the firewall. Can anyone tell me where this is supposed to go and what its function is? Thanks. Eric

That goes to your brake booster up front .its a steel line inside the car and terminates at a rubber hose up front by the brake booster

It runs under the center console, but I doubt the leak is inside the cabin. You could replace the rubber hoses on the ends for insurance though. Also remember that the LQ1's are natorious for having a lower to middle intake leak. Might want to freshen up those gaskets if you can.