Vacuum Pump Problem

[petervankleeck]

1990 #659

Gentlemen,

If I disconnect the first vacuum line connector near the alternator, and put my thumb over the line from the pump closing it off, shouldn't the pump stop running? This pump keeps running when the line is closed with my finger. It does draw some vacuum but not enough to stop the pump?

Any help would be appreciated. My first thought was to purchase another pump but I wanted to check here to see if there was something I was missing.

Thanks!

Peter

[TX '90 ZR1]

1990 #659

Gentlemen,

If I disconnect the first vacuum line connector near the alternator, and put my thumb over the line from the pump closing it off, shouldn't the pump stop running? This pump keeps running when the line is closed with my finger. It does draw some vacuum but not enough to stop the pump?

Any help would be appreciated. My first thought was to purchase another pump but I wanted to check here to see if there was something I was missing.

Thanks!

Peter

Peter,
You are correct that it should cut off in this situation.
I'd check the line to the pump and make sure it is not leaking. If not I would assume it is an issue with the cutoff in the pump or the pump itself.
I am not sure if these are repairable. Maybe a greater mind than mine will chime in with more thoughts.
:cheers:

[petervankleeck]

Thanks Ken for your reply.

I did check the line after I initiated the thread and the line looks good. I plugged the outlet port on the pump and could not get it to stop.

It would be great to know if it can be repaired or to hear from someone who has done the work.

Thanks again.
Peter

[dredgeguy]

Peter,
If you can wait until Jim gets back from his Utah trip in a couple of weeks you can bring your car up to our Wazoo maintenance day in Westminster, MD. If you want to get this taken care of sooner, contact Dempsey at his shop in Fredericksburg, VA
http://www.evolution-motorsport.com/locations.html.
Keep us posted.

[petervankleeck]

Thanks Charlie,

When is your next WAZOO maintenance day?

Peter

[dredgeguy]

When Jim gets back from his cross country trip. He will be back around June 15 so likely the following weekend.

[petervankleeck]

Resolution: I purchased a used 1990 ZR1 vacuum pump I found on Ebay, identical to mine. Plugged everything in and the pump works as designed. Turn the key on, it runs for a few seconds (good vacuum), cuts off and we're on our way.