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To be perfectly honest, I have no idea if it says "lift" on the dash. I've never looked while pushing the button. I'll have to pay attention to that next time. I've tried to use it as little as possible (and with 3 weeks straight of rain in Houston, that hasn't been too hard *cry*). I'm reluctant to let the dealer tinker with it and hand me a $4,000 bill.
mine was same. Go up, no down. Dealer repaired this year. It was only the switches. I posted the part numbers in another thread on this same topic. Parts were like 450 I f I remember.
only three switches on it. All made by SUCO. One for lift indication 13bar, one for lowered indication 1bar, and last switch mounted on cylinder regulator to cut the DC motor on the compressor off when tank reaches 18 bar.
looking at the other thread the components circled are NOT the switches. These components are the 2way solenoid valves for lift and lowering.
Thanks for pointing that out. In your post #190 you mention a third solenoid valve. What does this one do?
The third is a dump valve. It’s the one that causes the nice hissing sound when the system lowers. It re-channels the air coming out the shock chambers back through the system inlet air filter in the reverse direction.
This dump valve is actually another two valves. One is electrical solenoid actuated. This one forces air towards the pneumatically actuated dump valve which when actuated changes the exit air direction out the air filter.
Pushing the FAL button in the car to lower the system causes not only the lowering valve to actuate, but also the dump valves.
I wrote this attached document for myself where I reverse engineered the system to allow me to build my tester. Hopefully it will help as it walks through what happens when the system charges, lifts, and lowers. It might have errors in it as it was never intended to be published.
I've made the decision to use mine sparingly, and not to use it during the ultra hot and humid summer months.
I have a large craftsman compressor, and when it's empty I open the bottom valve on the tank and water comes out. So I wonder where the water goes on the FAL system, probably through the section that makes the swoosh sound-
I've made the decision to use mine sparingly, and not to use it during the ultra hot and humid summer months.
I have a large craftsman compressor, and when it's empty I open the bottom valve on the tank and water comes out. So I wonder where the water goes on the FAL system, probably through the section that makes the swoosh sound-
The third is a dump valve. It’s the one that causes the nice hissing sound when the system lowers. It re-channels the air coming out the shock chambers back through the system inlet air filter in the reverse direction.
This dump valve is actually another two valves. One is electrical solenoid actuated. This one forces air towards the pneumatically actuated dump valve which when actuated changes the exit air direction out the air filter.
Pushing the FAL button in the car to lower the system causes not only the lowering valve to actuate, but also the dump valves.
I wrote this attached document for myself where I reverse engineered the system to allow me to build my tester. Hopefully it will help as it walks through what happens when the system charges, lifts, and lowers. It might have errors in it as it was never intended to be published.
Good point.. If you look at page six of the document I wrote the compressor has an onboard air dryer. I haven't opened it up, but I guess its a crystal based chemical dryer? My concern is shock hydraulic fluid knackering it longterm?
Last edited by cdixon; 08-15-2021 at 04:44 PM.
Reason: Quoting wrong reply!
I've made the decision to use mine sparingly, and not to use it during the ultra hot and humid summer months.
I have a large craftsman compressor, and when it's empty I open the bottom valve on the tank and water comes out. So I wonder where the water goes on the FAL system, probably through the section that makes the swoosh sound-
Great work, big round of applause for cdixon
See previous reply from me.... Quoting wrong reply!!!
@cdixon: I enjoyed reading your pdf document. It is very informative. Thank you for sharing it. Any idea why Porsche is not providing a better support for this system? It may not be a flawless design but it certainly is worth servicing it, no? The fact that you couldn't order the belt directly from Porsche doesn't make any sense. You would also think that they have come up with a workshop troubleshooting guide to quickly diagnose common issues. This would safe valuable time for everyone.
This is not an important question, in case the reservoir pressure dropped below 18 bar, does the pump come on as soon as the ignition is turned on or must the engine be running? Thanks.
@cdixon: I enjoyed reading your pdf document. It is very informative. Thank you for sharing it. Any idea why Porsche is not providing a better support for this system? It may not be a flawless design but it certainly is worth servicing it, no? The fact that you couldn't order the belt directly from Porsche doesn't make any sense. You would also think that they have come up with a workshop troubleshooting guide to quickly diagnose common issues. This would safe valuable time for everyone.
This is not an important question, in case the reservoir pressure dropped below 18 bar, does the pump come on as soon as the ignition is turned on or must the engine be running? Thanks.
Thanks for your kind words. I’m a bit of an OCD engineer when I get going and I don’t like technology getting the better of me!
I think it all comes down to cost and the fact the cars are now over ten years old. I guess maybe half the cars built had this option so not a high volume were ever made, therefore doesn’t justify building a support model for them. That being said a couple of things really irritate me about it. If the belt is a non Porsche replaceable part, why put an inspection cover on the unit for the belt? Lots of indies seem to offer two prices for a complete unit. First price is for a complete replacement, second is for a swap out replacement. This tells me with the second option someone is repairing them? What I have found here in the UK is that OPCs don’t generally have 997 skills anymore and the average Joe technician looks at you like your some kind of mad professor when he’s trying to convince you it’s a highly technical black box and you respond telling them how the electro pneumatic system works.
The other thing I found on my research is that I couldn’t find a replacement DC motor ( didn’t look that hard though) and all the solenoid pneumatic valves cannot be bought anymore. They were originally made by a small pneumatic valve company here in Bristol where I live. That company was taken over by Norgren who after a few years discontinued them.
To answer your final question. The engine needs to run. I suspect this is because the DC motor on the compressor has a high power draw. Also the system can make a bit of noise when charging, so you need the engine to drown it out!
Thanks for helping me to understand how this system actually works. Mine was completely replaced under warranty about eight years ago. Nose would go up with the button (no "Lift" in cluster) and would only lower with speed. Now I know which part (most likely the 13 bar pressure switch 997.341.967.90) to replace in case I end up with the same issue.
Had a play with my new PIWIS3 to get a complete understanding of the 997.2 FAL. It’s as simple to code and troubleshoot in the diagnostics as I found the hardware troubleshooting of the unit itself.
The FAL control is nested in a special version of the Rear Control Unit as I mentioned in the thread above. In addition it has two external relays and a fuse, all of which are located on the rear relay carrier (Panel under the rear parcel shelf) The Rear Control Unit is nested under the seat.
To code and troubleshoot the FAL you need to select the Rear Control Unit > Vehicle Type > Then select the appropriate drop down option and write it. I have attached some screen shots and also a breakdown of the car wiring diagram for the FAL.
I may have missed it, does PIWIS allow you to operate the lift for testing? Would it store any error codes like in case of a pressure switch failure? When my system was completely replaced under warranty they said that they couldn't find any error codes. Makes me wonder if they even looked.
I may have missed it, does PIWIS allow you to operate the lift for testing? Would it store any error codes like in case of a pressure switch failure? When my system was completely replaced under warranty they said that they couldn't find any error codes. Makes me wonder if they even looked.
correct it does allow you to operate the system. It has three separate tests available.
1) Lift the system
2) lower the system
3) activate compressor pump
it will record in the test mode that the switches are open or closed. Also I have seen the cars control unit log a FAL fault, but I am not sure it it would log the individual component failure. Having said that running the three tests I mentioned above would help you to isolate the fault
08-14-2021, 06:16 PM
