WSW Door Hyperactivity

[Tony H.]

A while ago (last year for about two years) the windshield wiper door would rise and settle back into place as I started up my 1970 Corvette. This year until now, it had not done that. Today I saw a hint of that hyperactivity again. Each time, the door settles to its normal closed position after briefly saying hello to me. It seems to be the onset of a leak in one of the several valves. I did order a vacuum troubleshooting guide from NCRS but would like to hear from others who have experienced this phenomenon or have some insight on solving this problem.

Thanks very much.

Tony

[Tom B.]

Re: WSW Door Hyperactivity

Tony,

I'm by no means a by-the-book expert but I just had the experience of re-wiring my main (dash) harness in my 68 this last winter and it included a tangle with the vacuum system.

You are on the right track with the Vacuum Troubleshooting Guide you ordered. It will detail the entire system to the point that you can take it apart and put it back together correctly.

I still have the original hoses on my vacuum system and at one place, the WSW door vacuum cannister (under the hood on the right), they don't grip their connection as tight as they should (age). What this causes for me, if they're not on just right, is some sporatic play or sometimes inactivity. While you're waiting for the troubleshooting guide and before you start replacing all the valves and components, make sure your hoses are leading to the right place (as best as you can), but most importantly, that they have a good connection. There are several places to check that include (but aren't limited to): the intake manifold (where the system draws it supply), the valves and cannisters, both over-ride valves, and even the headlight vacuum components since they draw from the same system.

If you have to get behind the dash, be extremely patient, it's a tight space. Be careful not to destroy something else in the process. You may know alot of this already, so just take it as a reminder. Hope this can help. If I can think of something else I did or came across then I'll let you know. Tom

[Tom B.]

Re: WSW Door Hyperactivity

Tony,

I'm by no means a by-the-book expert but I just had the experience of re-wiring my main (dash) harness in my 68 this last winter and it included a tangle with the vacuum system.

You are on the right track with the Vacuum Troubleshooting Guide you ordered. It will detail the entire system to the point that you can take it apart and put it back together correctly.

I still have the original hoses on my vacuum system and at one place, the WSW door vacuum cannister (under the hood on the right), they don't grip their connection as tight as they should (age). What this causes for me, if they're not on just right, is some sporatic play or sometimes inactivity. While you're waiting for the troubleshooting guide and before you start replacing all the valves and components, make sure your hoses are leading to the right place (as best as you can), but most importantly, that they have a good connection. There are several places to check that include (but aren't limited to): the intake manifold (where the system draws it supply), the valves and cannisters, both over-ride valves, and even the headlight vacuum components since they draw from the same system.

If you have to get behind the dash, be extremely patient, it's a tight space. Be careful not to destroy something else in the process. You may know alot of this already, so just take it as a reminder. Hope this can help. If I can think of something else I did or came across then I'll let you know. Tom

[Tony H.]

Re: WSW Door Hyperactivity

Thanks for your comments. I'll check the fittings and try some silicone to tighten the seal at the ends of the hoses before I do anything more drastic.

[Tony H.]

Re: WSW Door Hyperactivity

Thanks for your comments. I'll check the fittings and try some silicone to tighten the seal at the ends of the hoses before I do anything more drastic.

[Chuck G.]

Re: WSW Door Hyperactivity

I agree with Tom 100%. Check all of your vacuum connections. I had similar problems with my wiper door popping up when I started the car. It also popped up when I "stomped" on the gas pedal. I found that some of the rubber hoses had "mushroomed" over the years from being pushed over the various vacuum nipples. I'm sure that they were leaking somewhat. I took a straight razor blade and cut off about 1/4 inch from each vacuum hose end and pushed them back on again. This solved my problem, so far. Hope this helps. Chuck

[Chuck G.]

Re: WSW Door Hyperactivity

I agree with Tom 100%. Check all of your vacuum connections. I had similar problems with my wiper door popping up when I started the car. It also popped up when I "stomped" on the gas pedal. I found that some of the rubber hoses had "mushroomed" over the years from being pushed over the various vacuum nipples. I'm sure that they were leaking somewhat. I took a straight razor blade and cut off about 1/4 inch from each vacuum hose end and pushed them back on again. This solved my problem, so far. Hope this helps. Chuck

[Patrick H.]

Re: WSW Door Hyperactivity

Tony,

As mentioned by myself before, others now, and even by yourself, it points to a leak SOMEWHERE in the system. My door does the exact same thing, and after using Dr Rebuild's vacuum guide I found that my left headlight vacuum canister has a small leak in it. And yes, I have a new outer seal in it.

Anyway, at $100 for a new canister, I have put up with the "wink" for a while.

What is occurring is that the wiper door vacuum canister and switch don't see vacuum when you first start the car (as it has all "leaked" out, or is it leaked in?) so they believe you are telling the door to lift. When the vacuum system then "fills" (or empties) a minute or so later, the correct signal is reapplied, and the door closes as it should.

As previous, I do recommend getting both the Dr Rebuild AND MidAmerica/NCRS guides, as they complement each other.

Of course, all of this assumes, as the others have mentioned, that you have ruled out bad/leaky connections and/or hoses.

Patrick Hulst

[Patrick H.]

Re: WSW Door Hyperactivity

Tony,

As mentioned by myself before, others now, and even by yourself, it points to a leak SOMEWHERE in the system. My door does the exact same thing, and after using Dr Rebuild's vacuum guide I found that my left headlight vacuum canister has a small leak in it. And yes, I have a new outer seal in it.

Anyway, at $100 for a new canister, I have put up with the "wink" for a while.

What is occurring is that the wiper door vacuum canister and switch don't see vacuum when you first start the car (as it has all "leaked" out, or is it leaked in?) so they believe you are telling the door to lift. When the vacuum system then "fills" (or empties) a minute or so later, the correct signal is reapplied, and the door closes as it should.

As previous, I do recommend getting both the Dr Rebuild AND MidAmerica/NCRS guides, as they complement each other.

Of course, all of this assumes, as the others have mentioned, that you have ruled out bad/leaky connections and/or hoses.

Patrick Hulst

[Jack H.]

Re: WSW Door Hyperactivity

You're on the right track with the troubleshooting guide and others have given you solid advice. But, troubleshooting guides that I've seen only speak to potential energy considerations and sort of ignore kinetic vac energy issues. What the heck is he saying??

You normally look for leaks with the engine idling and the vac system has obtained steady state status. So, as you go here/there with your vac meter you're seeing potential engergy (pressures that don't change). When you first start the car, actuate a vac component, accel/decel, air moves throughout the system to do work (kinetic energy).

There are actuator paths and control paths in the 'plumbing'. When you first start the car, the engine draws vac that charges the storage tank. It's kept there by the check valve so things to 'dance' when system disturbances (kinetics) occur. With the system 'dry' and the engine starts, ALL branches see vac energy at the same time.

This initiates 'race' conditions (who'll get vac first) and the hose diameter/length characteristics were designed to guarantee a 'bias' along specific paths to prevent chatter/oscillation due to race conditions. If the system's been breached for any appreciable time you've sucked foreign material inside. It's on hose wall ID surfaces as well as in the system filter.

Once you've found and fixed the leak(s) (don't assume there's only one), go the extra distance to replace the check valve and in-line filter. Then replace the filter regularly because foreign 'crud' can be expected to migrate over time. Once the system is leak free AND clean, 'dancing' things go bye bye. So, my advice is to tackle both the potential and kinetic energy aspects of the vac system and not just dwell on the potential energy items. You can get the system leak free and STILL see sporadic funnies on initial start and under heavy accel/decel until she's clean inside and foreign gunk that traps in the filter and check valve is gone.

[Jack H.]

Re: WSW Door Hyperactivity

You're on the right track with the troubleshooting guide and others have given you solid advice. But, troubleshooting guides that I've seen only speak to potential energy considerations and sort of ignore kinetic vac energy issues. What the heck is he saying??

You normally look for leaks with the engine idling and the vac system has obtained steady state status. So, as you go here/there with your vac meter you're seeing potential engergy (pressures that don't change). When you first start the car, actuate a vac component, accel/decel, air moves throughout the system to do work (kinetic energy).

There are actuator paths and control paths in the 'plumbing'. When you first start the car, the engine draws vac that charges the storage tank. It's kept there by the check valve so things to 'dance' when system disturbances (kinetics) occur. With the system 'dry' and the engine starts, ALL branches see vac energy at the same time.

This initiates 'race' conditions (who'll get vac first) and the hose diameter/length characteristics were designed to guarantee a 'bias' along specific paths to prevent chatter/oscillation due to race conditions. If the system's been breached for any appreciable time you've sucked foreign material inside. It's on hose wall ID surfaces as well as in the system filter.

Once you've found and fixed the leak(s) (don't assume there's only one), go the extra distance to replace the check valve and in-line filter. Then replace the filter regularly because foreign 'crud' can be expected to migrate over time. Once the system is leak free AND clean, 'dancing' things go bye bye. So, my advice is to tackle both the potential and kinetic energy aspects of the vac system and not just dwell on the potential energy items. You can get the system leak free and STILL see sporadic funnies on initial start and under heavy accel/decel until she's clean inside and foreign gunk that traps in the filter and check valve is gone.