ACD Shifter Lost CO2 Instantaneously

nhramnl · 09-09-2019, 03:18 PM

Was at Earlville this weekend, and in the first round of Super Stock, my car air-shifted 1-2 perfectly, but then wouldn't air-shift 2-3. I quickly manually shifted it, and when I got back to the trailer, the pressure gauges on top of the bottle were both at zero. I KNOW that earlier that morning, I had like 800 psi on the main (pre-regulator) gauge. It appears as though between the 1-2 and 2-3 shifts, the system emptied itself. Has anybody ever experienced this, and what did you find was the cause? I've refilled the bottle, but don't want to reinstall it until I understand what went wrong. Thanks for any response.

Mike Pearson · 09-09-2019, 03:47 PM

Most likely something blew out. Maybe a line, shift solenoid or the regulator diaphragm. Just hook it to your air compressor and test with soap water to see if you can locate the leak. On my car I have a Schrader valve on my cylinder and no regulator I just use air from the compressor and fill it each day if needed. I put 100 PSI in the bottle and it will usually last a whole weekend with out refilling

ss3011 · 09-09-2019, 04:22 PM

That problem just happened to my car . It was the regulator diaphragm which split . I called ACD , and they said they do not service the two gauge regulator anymore . I was hoping to just replace the diaphragm but there is no manufacturer name on the regulator . ACD now sells a non adjustable regulator that has one gauge , that shows the bottle pressure .

nhramnl · 09-09-2019, 05:14 PM

Thanks to both of you, guys. I agree that the instantaneous loss of that much pressure points to a failure of something that is supposed to stand-up to pressure. I will follow Mike's great suggestion to pressurize the system with a connection to an air compressor and start checking things with soapy water.

ss3011 · 09-09-2019, 08:11 PM

If the diaphragm is leaking the air will escape through the vent hole near the regulator adjustment screw .

I wonder if it would make sense to cycle the shift solenoid after the race day is over so the diaphragm isn't under stress when the car is in storage . I close the valve at the end of the day but haven't been cycling the solenoid . So the next time I get in the car both gauges are in exactly pressure reading . Certainly tells me the system is tight , keeps the diaphragm under pressure . If I cycle the solenoid the gauges will both go to zero , and will cause no load on the diaphragm .

David Daulton · 09-10-2019, 09:12 AM

My ACD three speed shifter did the exact same thing once and it ended up being the push in hose connector at the 2-3 solenoid. The sealing ring inside it cracked/blew apart. I replaced all of them with some higher quality ones.

nhramnl · 09-11-2019, 07:13 AM

Quote:

Originally Posted by David Daulton

My ACD three speed shifter did the exact same thing once and it ended up being the push in hose connector at the 2-3 solenoid. The sealing ring inside it cracked/blew apart. I replaced all of them with some higher quality ones.

Thanks again to all of you, guys. I think David got me onto something. This past weekend, after disconnecting my harnesses, I for some reason started laying the right-side lap belt across the top of the nylon lines that feed air to the shift solenoids. Before one run, the latch mechanism kinda caught on one of the lines, and I'll bet when I pulled on it a little to free it, I displaced or cracked something. It's really cool how this forum can help a guy solve a problem; the experiences of others stimulate a person's mind.

09-09-2019, 03:18 PM	#1
nhramnl Senior Member Join Date: Feb 2010 Posts: 504 Likes: 7 Liked 352 Times in 82 Posts	ACD Shifter Lost CO2 Instantaneously Was at Earlville this weekend, and in the first round of Super Stock, my car air-shifted 1-2 perfectly, but then wouldn't air-shift 2-3. I quickly manually shifted it, and when I got back to the trailer, the pressure gauges on top of the bottle were both at zero. I KNOW that earlier that morning, I had like 800 psi on the main (pre-regulator) gauge. It appears as though between the 1-2 and 2-3 shifts, the system emptied itself. Has anybody ever experienced this, and what did you find was the cause? I've refilled the bottle, but don't want to reinstall it until I understand what went wrong. Thanks for any response.

09-09-2019, 03:47 PM	#2
Mike Pearson VIP Member Join Date: Mar 2007 Posts: 2,318 Likes: 546 Liked 1,629 Times in 502 Posts	Re: ACD Shifter Lost CO2 Instantaneously Most likely something blew out. Maybe a line, shift solenoid or the regulator diaphragm. Just hook it to your air compressor and test with soap water to see if you can locate the leak. On my car I have a Schrader valve on my cylinder and no regulator I just use air from the compressor and fill it each day if needed. I put 100 PSI in the bottle and it will usually last a whole weekend with out refilling __________________ Mike Pearson 2485 SS Last edited by Mike Pearson; 09-09-2019 at 03:53 PM.

09-09-2019, 04:22 PM	#3
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 885 Likes: 63 Liked 221 Times in 102 Posts	Re: ACD Shifter Lost CO2 Instantaneously That problem just happened to my car . It was the regulator diaphragm which split . I called ACD , and they said they do not service the two gauge regulator anymore . I was hoping to just replace the diaphragm but there is no manufacturer name on the regulator . ACD now sells a non adjustable regulator that has one gauge , that shows the bottle pressure .

09-09-2019, 05:14 PM	#4
nhramnl Senior Member Join Date: Feb 2010 Posts: 504 Likes: 7 Liked 352 Times in 82 Posts	Re: ACD Shifter Lost CO2 Instantaneously Thanks to both of you, guys. I agree that the instantaneous loss of that much pressure points to a failure of something that is supposed to stand-up to pressure. I will follow Mike's great suggestion to pressurize the system with a connection to an air compressor and start checking things with soapy water.

09-09-2019, 08:11 PM	#5
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 885 Likes: 63 Liked 221 Times in 102 Posts	Re: ACD Shifter Lost CO2 Instantaneously If the diaphragm is leaking the air will escape through the vent hole near the regulator adjustment screw . I wonder if it would make sense to cycle the shift solenoid after the race day is over so the diaphragm isn't under stress when the car is in storage . I close the valve at the end of the day but haven't been cycling the solenoid . So the next time I get in the car both gauges are in exactly pressure reading . Certainly tells me the system is tight , keeps the diaphragm under pressure . If I cycle the solenoid the gauges will both go to zero , and will cause no load on the diaphragm .

09-10-2019, 09:12 AM	#6
David Daulton Junior Member Join Date: Aug 2013 Posts: 66 Likes: 1 Liked 19 Times in 4 Posts	Re: ACD Shifter Lost CO2 Instantaneously My ACD three speed shifter did the exact same thing once and it ended up being the push in hose connector at the 2-3 solenoid. The sealing ring inside it cracked/blew apart. I replaced all of them with some higher quality ones. __________________ David Daulton 3541