Air Grabber Actuator Function Question

[SixBarrelBill]

I'm just really curious as to how the air grabber actuator is supposed to function.

I'm currently checking the function on my car.

With the car off, I undo the hose on the nipple closest to the rod (which pushes the rod out and lifts the scoop) and put a vacuum pump on it. The rod will extend but constant vacuum must be applied, or the rod will no longer lift the door. Is this correct? Constant vacuum must be applied?

With the car off, I undo the hose on the nipple furthest away from the rod (which pulls the rod in and closes the scoop) and put a vacuum pump on it. The rod will pull back but once I stop pumping with the vacuum pump, the vacuum from the actuator slowly bleeds off. Is this correct?

As far as I can tell, at least on my car, no vacuum is actually held by the actuator itself.

@72ls5fla

 

[Beekeeper]

That is correct it needs constant vacuum to stay open but if using a vacuum pump once vacuum is pulled it should hold it unless there’s a leak in the hoses or diaphragm.

 

[Sinitro]

The air grabber system should have an in-line solenoid valve... When the engine is OFF the door can be held open..

Just my $0.02...

 

[RJRENTON]

The air grabber system should have an in-line solenoid valve... When the engine is OFF the door can be held open..

Just my $0.02...

NOT CORRECT.....The inline solenoid valve, allows the air grabber door to AUTOMATICALLY close, by bleeding off the vacuum to the actuator EVEN THOUGH the dash mounted air grabber VALVE (its NOT A SWITCH) is set to open. Conversely, with the air grabber VALVE set to the close position, the air grabber door will not open, regardless if the engine is running or not. My '70 GTX RS23V0A****** N-96 origional and totally functional system operates perfectly.
BOB RENTON

 

[Sinitro]

NOT CORRECT.....The inline solenoid valve, allows the air grabber door to AUTOMATICALLY close, by bleeding off the vacuum to the actuator EVEN THOUGH the dash mounted air grabber VALVE (its NOT A SWITCH) is set to open. Conversely, with the air grabber VALVE set to the close position, the air grabber door will not open, regardless if the engine is running or not. My '70 GTX RS23V0A****** N-96 origional and totally functional system operates perfectly.
BOB RENTON

Hmm..
Thanx for the info but my air grabber must be hooked up differently..
Originally didn't have any in-line solenoid connected, and the door would open/close with the dash switch. But if the door was open it would always close when the engine was OFF. Later I did install the in-line solenoid but now the door will remain open and/or closed depending upon the dash switch position when the engine is off. I do have the OE factory hose hookup schematic I will recheck it.

Just my $0.02...

 

[RJRENTON]

Hmm..
Thanx for the info but my air grabber must be hooked up differently..
Originally didn't have any in-line solenoid connected, and the door would open/close with the dash switch. But if the door was open it would always close when the engine was OFF. Later I did install the in-line solenoid but now the door will remain open and/or closed depending upon the dash switch position when the engine is off. I do have the OE factory hose hookup schematic I will recheck it.

Just my $0.02...

The "secret" to the correct operation is the under dash solenoid valve AND the correct orientation and connection of the dash mounted air grabber VALVE.

• Do you have the vacuum resivoire mounted on the firewall and plumbed correctly?
• Do you have the vacuum hoses connected to the actuator correctly? Rod end vacuuum connection of the actuator is the OPEN connection. The opposite end vacuum connection is the CLOSE connection.
• Air grabber valve set to open, engine OFF, under dash solenoid DE ENERGIZED, results in air grabber door is closed.
• Air grabber valve set to open, engine running, under dash solenoid is ENERGIZED, results in air grabber door is open.
  
• Air grabber valve set to CLOSE, engine running, under dash solenoid is ENERGIZED, results in air grabber door is closed. (Air grabber door closed to keep rain water out of air cleaner element). Vacuum is applied to opposite rod end connection of the actuator, resulting in the keeping the air grabber closed.
  
• Air grabber valve set to open, engine was running, ignition switch OFF, but just shut down , under dash solenoid is DE ENERGIZED by venting vacuum, results in air grabber door CLOSING AUTOMATICALLY by spring tension on actuator mechanism.
  
• Air grabber valve set to open, engine OFF ignition switch ON, under dash solenoid is ENERGIZED, results in air grabber door is open, AND IS HELD OPEN by residual vacuum in the resivoire.
  
• Many viewers will comment this system is just like GM's COWL INDUCTION SYSTEM. ANSWER: Absolutely not....vacuum operates the system to open and hold it open conversely, the GM system holds the actuator closed and a spring opens it......just the opposite of Mopar

Check your wiring and hose connections, and valve connection and if the vscuum resivoire is holding vacuum and plumbed corectly and if the under dash solenoid is plumbed correctly and is connected correctly and GROUNDED.
BOB RENTON

 

[72RoadrunnerGTX]

Originally didn't have any in-line solenoid connected, and the door would open/close with the dash switch. But if the door was open it would always close when the engine was OFF.

Your description of how it worked originally indicates there was a solenoid in place and functioning as designed. As mentioned, the sole purpose of the solenoid valve is to close the A/G if the switch is in the open position and the key is turned off. If your door remains up with the key off, something is amiss.

 

[RJRENTON]

Your description of how it worked originally indicates there was a solenoid in place and functioning as designed. As mentioned, the sole purpose of the solenoid valve is to close the A/G if the switch is in the open position and the key is turned off. If your door remains up with the key off, something is amiss.

IF the OP has gone to the trouble and expense of retrofitting an air grabber system WHY would you NOT WANT it to functional correctly? There are NOS and repro solenoid valves available as well as the correct air grabber VALVE as well as people that repair actuators. To me something that doesn't operate as intended is worthless, other wise, why do it in the first place? Just asking.....
BOB RENTON

 

[Sinitro]

Wow...
Thanks guys for the air grabber operation info. I must have something different, but 1 thing I do like the way my air grabber operates is that @car show/cruise, engine off, hood down the door remains open.. I will recheck the hookup both for the vacuum lines and in-line solenoid 12V lead...

Just my $0.02..

 

[RJRENTON]

Your description of how it worked originally indicates there was a solenoid in place and functioning as designed. As mentioned, the sole purpose of the solenoid valve is to close the A/G if the switch is in the open position and the key is turned off. If your door remains up with the key off, something is amiss.

YES.....you are correct....if the system does not operate as outlined, something as installed or plumbed incorrectly. On the 1970 Plymouth models (and probably Dodge as well), the N-96 system uses a 3 port dash mounted toggle VALVE (not a switch as it has no wires attached only hoses) that ports the vacuum supply to the electrically operated solenoid valve and air grabber door's vacuum actuator. The prior cold air induction systems were cable operated

Im not sure how the dash mounted air grabber vacuum VALVE became known as a switch?? or why. I suppose, perhaps out of ignorance or lack of understanding....which is understandable. Many people call the engine a motor....but a motor operates on electricity not ihternal combustion....but....with the onslaught of the pending EV revolution, perhaps, we old timers (me), should "adjust" our thinking to a broader, more generalized mind set (not) .... an engine is not a motor and a valve is not a switch.....although nomenclature and parlance will likely change to suit the audience and time..... Just my opinion of course....
BOB RENTON

 

[Sinitro]

As I posted previously I greatly appreciate the input provided for the proper hookup and operation for the vacuum air grabber system. However a strange thing has happened... I have received 5 PMs requesting more info & specifics on my hookup system. As they would like to revise their air grabber system to be able to keep the door to stay open, when the engine and ignition is switched OFF. This coming weekend, I will check out my system hose/electrical hookup method and post the schematic. It is not in my interest to debate how the air grabber system should function but rather provide further info for an alternate hookup method and operation....

Just my $0.02...

 

[Photon440]

Well, to be fair, the engineers who developed the air grabber system called the switching device a ... switch.

https://bestride.com/news/entertainment/grammar-nerd-should-you-call-it-a-motor-or-an-engine

 

[RJRENTON]

As I posted previously I greatly appreciate the input provided for the proper hookup and operation for the vacuum air grabber system. However a strange thing has happened... I have received 5 PMs requesting more info & specifics on my hookup system. As they would like to revise their air grabber system to be able to keep the door to stay open, when the engine and ignition is switched OFF. This coming weekend, I will check out my system hose/electrical hookup method and post the schematic. It is not in my interest to debate how the air grabber system should function but rather provide further info for an alternate hookup method and operation....

Just my $0.02...

I understand your position....but....out of curiosity WHY do you want the air grabber door to stay open with the hood closed and the engine OFF?? If that is your desire, the vacuum system must be in top notch condition, especially the one way check valve on the vacuum resivoire that connects to the intake manifold vscuum source and there are zero leaks in the system. You should also REMOVE the closing spring on the actuator linkage. However there is a link and a write up on this site, to install a ELECTRICAL LINEAR ACTUATOR using a toggle SWITCH to open and close the air grabber door, which must be powered open or closed and it remains in last position either open or closed.....perhaps this is the information you seek. I prefer the origional methodology...... just my opinion of course...
BOB RENTON

 

[RJRENTON]

Well, to be fair, the engineers who developed the air grabber system called the switching device a ... switch.
View attachment 1276478

https://bestride.com/news/entertainment/grammar-nerd-should-you-call-it-a-motor-or-an-engine

Thanks for the insight.....when I learned mechanical engineering and electrical engineering equipment, switches conttolled things electrical and valves conttolled things pneumatic or fluids.....sort of like talking about tomatoe or tomoto and potatoe or pototo.....its what was learned way back in time.....which is correct??? In the grand plan of life, it doesn't really matter......the same could be true of the engine vs motor nomenclature.....
BOB RENTON

 

[mopar jack]

I have 71 road runner with air grabber and the first thing I wanted to do at car shows was keep the air grabber door open when parked for display. The simple solution was to remove the spring at the vacuum diaphragm valve.

 

[Sinitro]

I go to more cruises than shows, and I prefer to keep my hood closed. But always get many questions about the air grabber system. With the scoop/door open the RR shows off well.

Just my preference…