Vacuum leak

[JimBobTX]

I have just purchased my 1990 ZR1 last month, which has just over 26,000 miles and I have a couple of problems to try to resolve. The first is a vacuum leak. I can hear the vacuum pump running from the time I turn the key until I start the car and don't know where to start to resolve the problem. I am not a mechanic but can do some basic repair work. Does anyone know where to get a diagram of the vacuum system on the LT5? I have noticed that there is a vacuum line off of one of the parts to the car that is located in the front right side of the car below the headlight. I can see where the vacuum line should be but I cannot find the line, nor do I know where it would go. The part that the vacuum line attaches too is made in Germany and has two numbers on it. One is 10098414 (near the top) and 003-953-06 near the bottom. This part also has an electrical connection going to it.
Thanks

[32valvZ]

Post some pics of your car in the general section! :cheers:

[Ccmano]

Can you post a picture?
H
:cheers:

[JimBobTX]

I have uploaded a picture of the part referenced above. It is located below the right head light. It can be see that there is no vacuum line attached to the lower, white, connector on the left side of the part. I have looked and cannot find any vacuum lines on that side of the engine that are not connected. My problem is that I don't know where the lines should go. The connection that is above the white one does have a line that goes behind the oil filter.

[S.hafsmo]

I believe that white connector is the outlet of the pump. The hose with the 90° elbow on the left in the photo is the hose that goes to below the plenum.

[Ccmano]

That’s the vacuum pump. Does it stop running when you start the engine?
H

[JimBobTX]

I am out of town today but will check tomorrow to see if it shuts off when the engine is running. Thanks

[JimBobTX]

When I turn the ignition switch the pump cycles about 1 second on and one second off but once I start the car it goes off. Does anyone have a picture of their vacuum pump so I can see what is connected to the lower, white, connection on mine? Thanks

[S.hafsmo]

By outlet, I mean that is where the air is vented to atmosphere. You should feel a small amount of air coming out there when the pump is running. More if you pull off the elbow next to it.

[S.hafsmo]

1s cycle indicates leakage. Probably the check valve between secondary system and plenum.
You can check this by removing the vacuum line connected to the driver side of the plenum, between the runners, and plug the hose. If the pump stops cycling, or extends the interval, at least you've isolated one fault.

[A26B]

..................….what is connected to the lower, white, connection...………...

Nothing