Secondary Port Throttle Vacuum motor - ZR-1 Net Registry Forums

DennisD · 03-19-2020

This is my first post and I am glad to be a member and owner of a 94 ZR1
I noticed I was having slightly higher than spec'd idle rpm. 900-1000.
display noted some issue.
I looked at the post by Marc Haibeck and I checked to see if my vacuum motor turned on immed after keyed to ON position.
No sound at all. It was gettin 12vdc.
I took the motor out and bench tested it and it didn't work.
Took it apart (see 2nd image) and it was fried. looks like water got into it from the white inlet inlet nipple.
I ordered a replacement but I need some advise as I think I have a better way of routing the inlet air via a hose higher up in the area with a modified protector so water cant get in.
Your suggestions are welcome

Ccmano · 03-19-2020

The reason it’s fried is more likely you have a vacuum leak in the secondary system which allowed the pump to run continuously and burn out. When you install the new one make sure it cycles on a off as it should with just the key on and off when the engine is idling. The motor on these is sealed and shouldn’t be affected by water, only the connections are susceptible to corrosion.
H

jss06c6 · 03-19-2020

Hans is on it. The hint is that your idle is high, suggesting a vacuum leak..

Sent from my SM-G950U using ZR-1 Net Registry mobile app

DennisD · 03-20-2020

Quote:

Originally Posted by Ccmano

The reason it’s fried is more likely you have a vacuum leak in the secondary system which allowed the pump to run continuously and burn out. When you install the new one make sure it cycles on a off as it should with just the key on and off when the engine is idling. The motor on these is sealed and shouldn’t be affected by water, only the connections are susceptible to corrosion.
H

Thanks. I ll check with a hand vacuum pump.

DennisD · 03-20-2020

Quote:

Originally Posted by DennisD

This is my first post and I am glad to be a member and owner of a 94 ZR1
I noticed I was having slightly higher than spec'd idle rpm. 900-1000.
display noted some issue.
I looked at the post by Marc Haibeck and I checked to see if my vacuum motor turned on immed after keyed to ON position.
No sound at all. It was gettin 12vdc.
I took the motor out and bench tested it and it didn't work.
Took it apart (see 2nd image) and it was fried. looks like water got into it from the white inlet inlet nipple.
I ordered a replacement but I need some advise as I think I have a better way of routing the inlet air via a hose higher up in the area with a modified protector so water cant get in.
Your suggestions are welcome

I attached the vacuum pump. pumped to 15. it took about 2 minutes to go to 10. Do you thin k this is ok?

Ccmano · 03-20-2020

Now go over to the driver side of the plenum and pull the vacuum line from the center and plug the line with a small bolt, golf tee or some such. Then go back and do your vacuum test again in the same place as before. If vacuum holds your check valve (under the plenum) is bad, if it still drops you have a leak elsewhere in the secondary system. If you can stand there and watch the vacuum gage go down the leak is substantial enough.
H

90zr1blknred · 03-25-2020

So I just looked at my 93 zr1 and I don’t have anything coming off my white tube either. It looks just like yours in the picture. Should something be connected to the white tube on the vacuum pump and if so where should it go. I don’t think mine shuts off either but my idle and secondaries work fine. Thanks for any input here as well.

DennisD · 03-25-2020

Quote:

Originally Posted by 90zr1blknred

So I just looked at my 93 zr1 and I don’t have anything coming off my white tube either. It looks just like yours in the picture. Should something be connected to the white tube on the vacuum pump and if so where should it go. I don’t think mine shuts off either but my idle and secondaries work fine. Thanks for any input here as well.

Mine did not turn on at all. When I took it apart it was fried. I just received my new one.
My thought although I may be wrong is because this white port sits low in the engine compartment it might suck in rain water. I am going to attach some black hose, to it, about a foot or so, shaped in an S configuration , secure it higher up. I am going to check some additional vacuum connections as suggested by CCmano

03-19-2020	#2
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,852	Re: Secondary Port Throttle Vacuum motor The reason it’s fried is more likely you have a vacuum leak in the secondary system which allowed the pump to run continuously and burn out. When you install the new one make sure it cycles on a off as it should with just the key on and off when the engine is idling. The motor on these is sealed and shouldn’t be affected by water, only the connections are susceptible to corrosion. H __________________ 90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold. Last edited by Ccmano; 03-19-2020 at 07:35 PM.

03-19-2020	#3
jss06c6 Join Date: Aug 2015 Location: Magnolia, Texas Posts: 884	Re: Secondary Port Throttle Vacuum motor Hans is on it. The hint is that your idle is high, suggesting a vacuum leak.. Sent from my SM-G950U using ZR-1 Net Registry mobile app

03-20-2020	#6
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,852	Re: Secondary Port Throttle Vacuum motor Now go over to the driver side of the plenum and pull the vacuum line from the center and plug the line with a small bolt, golf tee or some such. Then go back and do your vacuum test again in the same place as before. If vacuum holds your check valve (under the plenum) is bad, if it still drops you have a leak elsewhere in the secondary system. If you can stand there and watch the vacuum gage go down the leak is substantial enough. H __________________ 90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold.

03-25-2020	#7
90zr1blknred Join Date: Mar 2019 Location: Colorado - Denver Posts: 22	Re: Secondary Port Throttle Vacuum motor So I just looked at my 93 zr1 and I don’t have anything coming off my white tube either. It looks just like yours in the picture. Should something be connected to the white tube on the vacuum pump and if so where should it go. I don’t think mine shuts off either but my idle and secondaries work fine. Thanks for any input here as well.

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