vacuum issues,....

[rush91]

So I went to start up this Beast this morning, and it started but immediately died. I cranked her again and fired right up.......I have been getting a flashing climate control button. Which I diagnosed was a freon leak. I talked to Marc H and he said he converted the A/C for the previous owner. He said it probably is a vacuum leak. I tried to run the A/C and it just blew hot air, awesome!!! After letting it the car run for a few minutes, I shut it off and was going to start it again. but noticed as I turned the key I couldn't hear the vacuum pumps do there thing.......major issue? Or is it just tracking down the leak and simple fix??

[mgbrv8]

If you have to pull the plenum here are the pics of my pull I hope they help

https://www.facebook.com/media/set/?set=a.10201021415884459.2217036.1439230280&type=1&l=8f46fa4533

Dave

[Dynomite]

I turned the key I couldn't hear the vacuum pumps do there thing.......major issue? Or is it just tracking down the leak and simple fix??

One vacuum pump under passenger headlight. When you turn the key on (do not start) the vacuum pump should pump for about 3-5 seconds. Then stay off for minutes if you have no leaks. If you have vacuum leaks, the vacuum pump will cycle on and off. If the vacuum pump does cycle off for even a few seconds the secondaries will function normally.

If I understand your situation correctly :p

It sounds like you have an inoperable vacuum pump.

And you are mixing AC issues (you say you have R134a after the Marc Conversion) with Vacuum issues ....which the two issues have no association ;)

Add some R134a (you might have to jumper the AC low pressure switch during the replenishment of R134a).
If you have adequate AC pressure you will hear and can see the AC compressor Clutch engage. If the AC compressor Clutch does not engage, you most likely have lost AC pressure (the reason you have to jumper the AC low pressure switch during refilling of R134a).

[rush91]

One vacuum pump under passenger headlight. When you turn the key on (do not start) the vacuum pump should pump for about 3-5 seconds. Then stay off for minutes if you have no leaks. If you have vacuum leaks, the vacuum pump will cycle on and off. If the vacuum pump does cycle off for even a few seconds the secondaries will function normally.

If I understand your situation correctly :p

It sounds like you have an inoperable vacuum pump.

And you are mixing AC issues (you say you have R134a after the Marc Conversion) with Vacuum issues ....which the two issues have no association ;)

Add some R134a (you might have to jumper the AC pressure switch during the replenishment of R134a).
If you have adequate AC pressure you will hear and can see the AC compressor Clutch engage. If the AC compressor Clutch does not engage, you most likely have lost AC pressure (the reason you have to jumper the AC pressure switch during refilling of R134a).

My bad. You are right I am mixing two issues. I could always hear the pump under the headlight turn on when the ignition would be turned on, but not started. It then would buzz about every 10-15 seconds. Now I hear nothing except the fuel pump....... should I start to see if the vacuum fuse has blown? And would the secondaries be working if the vacuum pump wasn't working? The car seemed to run just fine, the secondaries opened up under throttle.

[Dynomite]

My bad. You are right I am mixing two issues. I could always hear the pump under the headlight turn on when the ignition would be turned on, but not started. It then would buzz about every 10-15 seconds. Now I hear nothing except the fuel pump....... should I start to see if the vacuum fuse has blown?

You could start with ignition key on and check for 12 v at the Vacuum Pump. If no 12 volts...then fuse or wiring....if 12 volts...then vacuum pump.
If vacuum pump....pressure sensing circuit or pump circuit.

Vacuum pump is a 10AMP IN-LINE fuse over near the grounds etc in the vicinity of the battery on the LH rear wheel-house panel? If you have a FSM it's in the image at 8A-201-8 in book 2.

Is that the same location of the Vacuum Pump Fuse for the 1990?

Thanks for the information......:thumbsup:

There it is, thanks a lot! It was blown so I changed it. Vacuum pump is now working.

Just inside and to the rear of the Drivers Side Front
Wheel House Panel almost directly below the Brake Cylinders
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite13/436dfdaf-f73f-4453-8bce-8c8ae7c219fc.jpg

Vacuum pump is now working.
However, it turns on every 2 seconds or so when key is on. Vacuum leak?


Yes...you have a vacuum leak ;)

Finding A Vacuum Leak (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-7.html#post1584987830)

[rush91]

You could start with ignition key on and check for 12 v at the Vacuum Pump. If no 12 volts...then fuse or wiring....if 12 volts...then vacuum pump.
If vacuum pump....pressure sensing circuit or pump circuit.

Thanks Dynomite!! Will try and see..... And on the A/C issue, it just blew hot air back to my face. Marc said the most common location for a refrigerant leak is at the high pressure side service port. Any way to check that, to see if it is leaking?

[Dynomite]

Thanks Dynomite!! Will try and see..... And on the A/C issue, it just blew hot air back to my face. Marc said the most common location for a refrigerant leak is at the high pressure side service port. Any way to check that, to see if it is leaking?

You are lucky you have R134a which is a lot cheaper to deal with :D

Google ac 134a leak detector and you will see all sorts of leak detectors.

I am assuming you have R134a??

[rush91]

You are lucky you have R134a which is a lot cheaper to deal with :D

Google ac 134a leak detector and you will see all sorts of leak detectors.

I am assuming you have R134a??

Yes I do, whew! Marc said he converted it over to R134a for previous owner....

[Dynomite]

This is an example of how bad the Vacuum Pump Condition can get Vacuum Pump Issues (http://www.zr1.net/forum/showthread.php?p=234500) :D

[rush91]

Well I disconnected the battery for a minute.....got back in car turn ignition on but didn't start the car. The vacuum pump was loud and working, and the code 09 reset. Can't be THAT easy of fix......rechecking all I can.

[rush91]

Sorry to throw this off topic, but as I was looking at vacuum pump, I saw this.....I didn't have my manuals and it was getting dark at storage unit. What is it and shouldnt it be plugged in??

[Dynomite]

Sorry to throw this off topic, but as I was looking at vacuum pump, I saw this.....I didn't have my manuals and it was getting dark at storage unit. What is it and shouldnt it be plugged in??

I have to look but that could be the under hood lights which most guys disconnect. If it was getting dark at storage unit with ignition on and hood up you prolly have those under hood lights disconnected :D

Did the Vacuum Pump run for a few seconds and then shut off for how many seconds?
If it ran and then shut off and ran again you are good to go and any vacuum leaks (depending on how long the vacuum pump rests) can be fixed at a later date with no loss in secondary function.

[rush91]

Well I disconnected the battery for a minute.....got back in car turn ignition on but didn't start the car. The vacuum pump was loud and working, and the code 09 reset. Can't be THAT easy of fix......rechecking all I can.


Well got WAY ahead of myself.......I let the car sit and idle, after about 10/minutes backed her back into storage unit. Went to restart and turned ignition and no vacuum pump. It buzzed for about 1 second and that's all. The 09 code reset, and remains so.

[Johnny5]

i have a vacuum pump I am selling if you are interested. PM if soi

[rush91]

I have to look but that could be the under hood lights which most guys disconnect. If it was getting dark at storage unit with ignition on and hood up you prolly have those under hood lights disconnected :D

Did the Vacuum Pump run for a few seconds and then shut off for how many seconds?
If it ran and then shut off and ran again you are good to go and any vacuum leaks (depending on how long the vacuum pump rests) can be fixed at a later date with no loss in secondary function.

After disconnecting the battery, and reconnecting it, turned ignition on. The pump ran as always for about 3-5 seconds and shut off. Car ran for about 10-15 minutes, then I shut it off. Went back to turn ignition on, and nothing.......No 3-5 second priming. The vacuum pump buzzed faintly for a second if that. I will go tonight with a flashlight, test all fittings without plenum pull. I'm just confused with what is going on. How can the pump run perfect after disconnecting the battery, then 15 minutes later nothing??

[rush91]

i have a vacuum pump I am selling if you are interested. PM if soi

I might be interested, going back tonight to run some tests.

[Dynomite]

After disconnecting the battery, and reconnecting it, turned ignition on. The pump ran as always for about 3-5 seconds and shut off. Car ran for about 10-15 minutes, then I shut it off. Went back to turn ignition on, and nothing.......No 3-5 second priming. The vacuum pump buzzed faintly for a second if that. I will go tonight with a flashlight, test all fittings without plenum pull. I'm just confused with what is going on. How can the pump run perfect after disconnecting the battery, then 15 minutes later nothing??

One of those anomilies that is hard to diagnose. If the Vacuum Pump ran perfectly and next time buzzed faintly....that sounds like a Pump issue. The easiest is to stick in a good pump to see if that runs. Nice to have a spare pump anyway. Sometimes the "stick in a good part" works easiest to isolate Anomilies.

I would first check voltage at the pump to make sure you have 12 volts and to make sure that voltage is not varying. The car will run fine without vacuum pump unless you have the power key on and you are in a mode where the secondaries will function. Then you will notice not as much power as you are prolly used to (when Plenum Vacuum is low and Power Key ON).

Check voltage at the Vacuum Pump Electrical Connector and if you have 12 volts, plug connector into the Vacuum pump. Now disconnect the Vacuum line from the pump ....which the pump should run continuously with vacuum line disconnected. (Key ON)

[rush91]

One of those anomilies that is hard to diagnose. If the Vacuum Pump ran perfectly and next time buzzed faintly....that sounds like a Pump issue. The easiest is to stick in a good pump to see if that runs. Nice to have a spare pump anyway. Sometimes the "stick in a good part" works easiest to isolate Anomilies.

I would first check voltage at the pump to make sure you have 12 volts and to make sure that voltage is not varying. The car will run fine without vacuum pump unless you have the power key on and you are in a mode where the secondaries will function. Then you will notice not as much power as you are prolly used to (when Plenum Vacuum is low and Power Key ON).

Check voltage at the Vacuum Pump Electrical Connector and if you have 12 volts, plug connector into the Vacuum pump. Now disconnect the Vacuum line from the pump ....which the pump should run continuously with vacuum line disconnected. (Key ON)

I will check the voltage, need to get autometer first. But I haven't noticed any lag in power or stumbling with the power key on. I get the same kick in the pants at 3000RPM as always. The car runs/ idles smooth as silk with power key on.

[Tripler]

Hey guys . Our newly purchased 1995 ZR-1 definitely has a vacuum leak as the pump keeps clicking every 3 to 5 secs . There are no fault codes on the dash and the car runs quite well . Will this leak be an issue for our drive to BG ?

Thanks

Mike

PS just read through the vacuum leak tech section . Thanks Dynomite . I will do the leak test prior to a removal of the plenum to at least confirm if the leak is not under the LT5's monster intake plenum ,,,

;) ;) ;)

[Dynomite]

Hey guys . Our newly purchased 1995 ZR-1 definitely has a vacuum leak as the pump keeps clicking every 3 to 5 secs . There are no fault codes on the dash and the car runs quite well . Will this leak be an issue for our drive to BG ?

Thanks

Mike

PS just read through the vacuum leak tech section . Thanks Dynomite . I will do the leak test prior to a removal of the plenum to at least confirm if the leak is not under the LT5's monster intake plenum ,,,

;) ;) ;)

Your 95' will drive fine as long as the vacuum pump DOES stop for a few seconds. Actually you could drive the Z without power switch on (like power switch was NOT on) for a long time with no issues. With FULL POWER The vacuum pump will just be working a lot harder which it prolly has for a long time.

For my 95' I installed Jerry's Secondary Vacuum System (http://www.jerrysgaskets.com/hose-secondary-port-throttle-vacuum-new-93-95-9b3) and now have zero vacuum leaks. It is amazing when you inspect original vacuum systems how many of the connectors actually leak.

Same goes with Jerry's PVC System new rubber components (one tube with dual PVC inlets, two Injector Housing Ls, and one Dual Connector on top of the Dual PVCs). NO MORE Nylon Ties, and NO MORE Hose clamps.

1995 LT5 SPECIFIC TOP END REBUILD TRICKS
A 1995 Top End was rebuilt and best tricks linked here
Post 230 - 1995 LT5 SPECIFIC TOP END REBUILD TRICKS (http://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-12.html#post1590759172)

[Tripler]

Your 95' will drive fine as long as the vacuum pump DOES stop for a few seconds. Actually you could drive the Z without power switch on (like power switch was NOT on) for a long time with no issues. With FULL POWER The vacuum pump will just be working a lot harder which it prolly has for a long time.

For my 95' I installed Jerry's Secondary Vacuum System (http://www.jerrysgaskets.com/hose-secondary-port-throttle-vacuum-new-93-95-9b3) and now have zero vacuum leaks. It is amazing when you inspect original vacuum systems how many of the connectors actually leak.

Same goes with Jerry's PVC System new rubber components (one tube with dual PVC inlets, two Injector Housing Ls, and one Dual Connector on top of the Dual PVCs). NO MORE Nylon Ties, and NO MORE Hose clamps.

1995 LT5 SPECIFIC TOP END REBUILD TRICKS
A 1995 Top End was rebuilt and best tricks linked here
Post 230 - 1995 LT5 SPECIFIC TOP END REBUILD TRICKS (http://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-12.html#post1590759172)

Awesome . Great to know . Yes with a 21 year old car , the rubber connections will have deteriorated indeed ...

I think I will definitely look into Jerry's PVC system . Sounds like a win win win ...

Thanks DY NO MITE !!! for the fast reply . :handshak::handshak::handshak:

[rush91]

Awesome . Great to know . Yes with a 21 year old car , the rubber connections will have deteriorated indeed ...

I think I will definitely look into Jerry's PVC system . Sounds like a win win win ...

Thanks DY NO MITE !!! for the fast reply . :handshak::handshak::handshak:

Dynomite is the man! I'd highly recommend his ALDL tester, a tool every Z owner should have. And it looks like a piece of art, highly recommend......

Well I finally got to my Beast, and ran a voltage test. Had between 11-12 volts. The pump ran for the 3-5 second priming when ignition turned on, then didn't buzz or run until 75 seconds later. Every 75-80 seconds it would buzz. Secondaries seem to be working as well......... Just curious, does heat have anything to do with vacuum pump not working or shutting off?? My Z seems to run hot after driving around awhile....