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When initially starting my '69, the wiper door immediately raises and then lowers with the wiper switch off. The entire vacuum system is new and the wipers and door function properly when the car is running. It seems that the primary vacuum circuit from the vacuum can to the relay to the wiper door actuator is getting vacuum before the secondary circuit from the solenoid behind the tach can tell the relay that the door should be closed. Is this a standard process when the car is initially started or am I overlooking something?
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Re: 69 Wiper Door Vacuum
It is not a standard reaction. You have a leak in your vacuum system somewhere. I had a similar problem and it ended up being the hose from the wiper selinoid to the override switch. It was not seated properly and lost vacuum. Check all your connections twice. These vacuum systems can be a real PITA. -
Re: 69 Wiper Door Vacuum
It is not a standard reaction. You have a leak in your vacuum system somewhere. I had a similar problem and it ended up being the hose from the wiper selinoid to the override switch. It was not seated properly and lost vacuum. Check all your connections twice. These vacuum systems can be a real PITA.Comment
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Also....
Wiper door's servo vac supply tees off the RH headlamp servo line (the two systems are in parallel), so leaks/faults in the related HL area can feedback or 'reflect' in the wiper door's operation. Understanding how the system is 'plumbed' and how it works helps a BUNCH in tracking and killing the typical 'funnies' that are encountered. There are MANY threads on this in the archives!
First a little theory, then two 'tips' follow. When car is started and vac begins to pull, there's a 'race condition' potential. The car has two independent vac systems (servo and control). The control system is what tells individual vac actuated devices to open/close. The servo system is path that actually does the physical work of opening/closing devices. System is designed to 'bias' against race condition transients on start-up/shut-down by way of hose diameter, length of individual hoses, Etc.
What's meant by a 'race' condition, is who sees/gets vac engergy first-the servo side or the control side? Obviously, we want the control side to see vac first, otherwise 'switches' may be left in random states and servo vac getting there first will cause 'dancing' HL buckets, wiper door etc, until the control side comes up and sets the switches accordingly....
In addition to gross leaks (don't expect to find just a SINGLE leak!), other considerations can/do perpetuate improper vac bias and 'dancing' components. Consider the servo side of the system is 'buffered' with a vac storage tank so there's vac energy set aside to do work when intake vac is inconsistent (heavy accel/decel). The storage tank can bias the system improperly is other system items are faulty.....
Tip one: Is your check valve operating properly? If not, EXPECT to see 'dancing' funnies. Pull it and test it (suck/blow) to see that this component is working crisp and true as it should be.
Tip two: The system has an in-line vac filter to prevent in-line airborne 'junk' from propagating into the intake manifold. This $4 part was intended to be replaced at least once a year and most owners NEVER service it! If the filter's plugged (pull it, hold it to the light and look through; you ought to see clean white gause), you've essentially changed the bias of the whole vac system by reducing air flow. Worse, eventually the filter element is going to plug so badly it'll be sucked/ripped through and wend its way into your intake manifold!!!!!Comment
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Also....
Wiper door's servo vac supply tees off the RH headlamp servo line (the two systems are in parallel), so leaks/faults in the related HL area can feedback or 'reflect' in the wiper door's operation. Understanding how the system is 'plumbed' and how it works helps a BUNCH in tracking and killing the typical 'funnies' that are encountered. There are MANY threads on this in the archives!
First a little theory, then two 'tips' follow. When car is started and vac begins to pull, there's a 'race condition' potential. The car has two independent vac systems (servo and control). The control system is what tells individual vac actuated devices to open/close. The servo system is path that actually does the physical work of opening/closing devices. System is designed to 'bias' against race condition transients on start-up/shut-down by way of hose diameter, length of individual hoses, Etc.
What's meant by a 'race' condition, is who sees/gets vac engergy first-the servo side or the control side? Obviously, we want the control side to see vac first, otherwise 'switches' may be left in random states and servo vac getting there first will cause 'dancing' HL buckets, wiper door etc, until the control side comes up and sets the switches accordingly....
In addition to gross leaks (don't expect to find just a SINGLE leak!), other considerations can/do perpetuate improper vac bias and 'dancing' components. Consider the servo side of the system is 'buffered' with a vac storage tank so there's vac energy set aside to do work when intake vac is inconsistent (heavy accel/decel). The storage tank can bias the system improperly is other system items are faulty.....
Tip one: Is your check valve operating properly? If not, EXPECT to see 'dancing' funnies. Pull it and test it (suck/blow) to see that this component is working crisp and true as it should be.
Tip two: The system has an in-line vac filter to prevent in-line airborne 'junk' from propagating into the intake manifold. This $4 part was intended to be replaced at least once a year and most owners NEVER service it! If the filter's plugged (pull it, hold it to the light and look through; you ought to see clean white gause), you've essentially changed the bias of the whole vac system by reducing air flow. Worse, eventually the filter element is going to plug so badly it'll be sucked/ripped through and wend its way into your intake manifold!!!!!Comment
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