Varioram not getting vacuum
06-10-2011, 01:01 AM
#1
Burning Brakes
Thread Starter
Varioram not getting vacuum
I'm coming to the brain trust before I rip all kinds of stuff off my engine. My vram is not working...noticed it at the last track day. Then I started thinking...when was the last time it WAS working...I can't remember. I went back to the last track video I had and it wasn't working then either. I say this only because the previous video was before I did a recent engine drop for LWF clutch so something was wrong beforehand.
What I've done to test so far:
- Per the manual I turned the car on...built up vacuum pressure...turned off. Then turned back on and watched for vram diaphram actuation when throttle is applied. Nothing moving.
- Tested several of the vacuum lines and all good vacuum except the three lines that go directly into the back of the vram diaphrams...no vacuum there at all.
- I pulled the "T" vram connector (which is less than a year old) and there is good vacuum comin from the white barbed connection.
- No sign of any audible leakes with engine on or off.
I've read a bunch of old posts but nothing has helped. Anyone have any obvious solutions/experience?
Thanks!
What I've done to test so far:
- Per the manual I turned the car on...built up vacuum pressure...turned off. Then turned back on and watched for vram diaphram actuation when throttle is applied. Nothing moving.
- Tested several of the vacuum lines and all good vacuum except the three lines that go directly into the back of the vram diaphrams...no vacuum there at all.
- I pulled the "T" vram connector (which is less than a year old) and there is good vacuum comin from the white barbed connection.
- No sign of any audible leakes with engine on or off.
I've read a bunch of old posts but nothing has helped. Anyone have any obvious solutions/experience?
Thanks!
06-10-2011, 01:32 AM
#2
Drifting
There is a vacuum diaphragm for each side of the intake manifold and also one down underneath the manifold, and it is not uncommon for them to fail. There is also a rubber "T" up by the firewall on the driver's side that has several vacuum lines attached that can get a kink in it. The cure for that one is to insert a thin wired spring inside it to hold the rubber to its shape. Maybe someone can come up with some pics from pcar.com before me. I'll see what I can find.
06-10-2011, 01:53 AM
#3
Burning Brakes
Thread Starter
There is a vacuum diaphragm for each side of the intake manifold and also one down underneath the manifold, and it is not uncommon for them to fail. There is also a rubber "T" up by the firewall on the driver's side that has several vacuum lines attached that can get a kink in it. The cure for that one is to insert a thin wired spring inside it to hold the rubber to its shape. Maybe someone can come up with some pics from pcar.com before me. I'll see what I can find.
06-10-2011, 02:15 AM
#4
Rennlist Member
Well, I'm not much help here (ask me a 3.2 question!), but can you work backwards? Can you rig a vaccum pump (A/C related-Harbor Freight?) to test? Seems like the process of elimination is in order, working down the line.
06-10-2011, 11:26 AM
#5
Hi Adam,
when you've carried out your vaccum checks, is this with the engine running or off? If you're checking with the engine running then the pipes will show a vaccum but the actuators will not cycle except when the ignition is first turned on.
You first need to establish whether the system holds vacuum with the engine off. It is not clear whether you removed the elbow at the back of the engine with it running or not. If there is a strong vacuum in the system with the engine off try the solenoids first. They are mounted at the bottom of the air intakes, one for bot the upper two actuators and one for the resonance flap. Ensure that vaccum is available here and after these when the varioram cycles.
If there is no vacuum with the engine off the diaphram in the vacuum unit at the back of the engine has failed. Common(ish) fault.
There is a vacuum tank is the left rear wheel well that has only one pipe running to it, this allows the system to cycle a few times before the vacuum is depleted (engine off). Make sure this is holding well when you get the actuators going by turning the ignition on and off. They should cycle multiple times before depletion.
Hope that helps
Regards
GR
when you've carried out your vaccum checks, is this with the engine running or off? If you're checking with the engine running then the pipes will show a vaccum but the actuators will not cycle except when the ignition is first turned on.
You first need to establish whether the system holds vacuum with the engine off. It is not clear whether you removed the elbow at the back of the engine with it running or not. If there is a strong vacuum in the system with the engine off try the solenoids first. They are mounted at the bottom of the air intakes, one for bot the upper two actuators and one for the resonance flap. Ensure that vaccum is available here and after these when the varioram cycles.
If there is no vacuum with the engine off the diaphram in the vacuum unit at the back of the engine has failed. Common(ish) fault.
There is a vacuum tank is the left rear wheel well that has only one pipe running to it, this allows the system to cycle a few times before the vacuum is depleted (engine off). Make sure this is holding well when you get the actuators going by turning the ignition on and off. They should cycle multiple times before depletion.
Hope that helps
Regards
GR
06-10-2011, 12:02 PM
#6
Nordschleife Master
All I can add, is test the AC with the car on. If you do have a vacuum leak, the AC will not work, it will sound like the fans are running a closed box.
The line to the AC is on the drivers side comes out near the shock mount.
The line to the AC is on the drivers side comes out near the shock mount.
06-10-2011, 12:27 PM
#7
Hi Adam,
when you've carried out your vaccum checks, is this with the engine running or off? If you're checking with the engine running then the pipes will show a vaccum but the actuators will not cycle except when the ignition is first turned on.
You first need to establish whether the system holds vacuum with the engine off. It is not clear whether you removed the elbow at the back of the engine with it running or not. If there is a strong vacuum in the system with the engine off try the solenoids first. They are mounted at the bottom of the air intakes, one for bot the upper two actuators and one for the resonance flap. Ensure that vaccum is available here and after these when the varioram cycles.
If there is no vacuum with the engine off the diaphram in the vacuum unit at the back of the engine has failed. Common(ish) fault.
There is a vacuum tank is the left rear wheel well that has only one pipe running to it, this allows the system to cycle a few times before the vacuum is depleted (engine off). Make sure this is holding well when you get the actuators going by turning the ignition on and off. They should cycle multiple times before depletion.
Hope that helps
Regards
GR
when you've carried out your vaccum checks, is this with the engine running or off? If you're checking with the engine running then the pipes will show a vaccum but the actuators will not cycle except when the ignition is first turned on.
You first need to establish whether the system holds vacuum with the engine off. It is not clear whether you removed the elbow at the back of the engine with it running or not. If there is a strong vacuum in the system with the engine off try the solenoids first. They are mounted at the bottom of the air intakes, one for bot the upper two actuators and one for the resonance flap. Ensure that vaccum is available here and after these when the varioram cycles.
If there is no vacuum with the engine off the diaphram in the vacuum unit at the back of the engine has failed. Common(ish) fault.
There is a vacuum tank is the left rear wheel well that has only one pipe running to it, this allows the system to cycle a few times before the vacuum is depleted (engine off). Make sure this is holding well when you get the actuators going by turning the ignition on and off. They should cycle multiple times before depletion.
Hope that helps
Regards
GR
Hope you are doing well.
To add to Tal's advice, if you determine there could be a vacuum leak block off each line one by one at the TT and check to see if the car holds vacuum when you turn the car off. When I was converting my varioram, I found that I had a vacuum leak near the front firewall (a vacuum line near the pollen filters was disconnected). The vacuum system in the 993 is interconnected.
Cheers,
Joe
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06-10-2011, 01:39 PM
#8
Burning Brakes
Thread Starter
Thanks very much all for the suggestions.
Guards Red, I think my process for checking the system might have been wrong after reading your post. After running the engine the first time to build up vacuum, I then turned it off and then restarted...I guess I need to not actually start it and see if it cycles.
Is the reason I get no vacuum at the vram actuators when the engine is running becuase the bottom actuator near the fan shrowd needs to open at certain rpm to allow the vacuum pressure to reach the top two diaphrams? If this is the case I would have expected this to have vacuum which it didn't. I guess I don't have a good understanding of the inner workings of the system which is not helping my ability to troubleshoot!
I didn't check to see if the system holds vacuum but will do that as well...easy enough. I did locate the reservior and will check that.
I'll report back once I have some more findings.
Guards Red, I think my process for checking the system might have been wrong after reading your post. After running the engine the first time to build up vacuum, I then turned it off and then restarted...I guess I need to not actually start it and see if it cycles.
Is the reason I get no vacuum at the vram actuators when the engine is running becuase the bottom actuator near the fan shrowd needs to open at certain rpm to allow the vacuum pressure to reach the top two diaphrams? If this is the case I would have expected this to have vacuum which it didn't. I guess I don't have a good understanding of the inner workings of the system which is not helping my ability to troubleshoot!
I didn't check to see if the system holds vacuum but will do that as well...easy enough. I did locate the reservior and will check that.
I'll report back once I have some more findings.
06-11-2011, 06:45 PM
#9
Burning Brakes
Thread Starter
Update...I did the proper test to check the system and found that the top driver side actuator and the lower bottom actuator cycled properly; however, the passenger top one did not. Also, I noticed that when the actuators cycled they did not hold...just went in and then came out pretty quickly. So, I pulled the vacuum line from the offending actuator and hooked the vacuum gauge up to it...cycled the system again and there it was! I had vacuum and the rest of the actuators stayed actuated. So, my problem is a faulty diaphram thingy. I'll be ordering a new one and hopefully problem solved!
Thanks for the suggestions.
Thanks for the suggestions.
06-21-2011, 12:48 AM
#12
Burning Brakes
Thread Starter
Okay, I wanted to updated this thread so it is finalized in case someone runs into this in the future. I ordered a new diaphram actuator from FD...got it today and put it on...took 10 minutes. I did the diagnostic test to cycle the system and this time when it cycled the actuators stayed open...it's fixed! Took it for a test drive and all was right in the world again, vram kicked in just as it should. 
Case closed!
Case closed!
