The previous owner of my LR3 paid $1,900 to have a new Arnott P-3431 compressor installed. (It still needed new air struts and an A/C compressor. That's when she listed it for sale.) This Arnott unit has a pneumatic solenoid exhaust valve that took me a day and a half of troubleshooting to figure out it was stuck closed. I believe the electromagnet is essentially too weak where a slightly sticky valve overpowered the magnet. Hopefully it will stay unstuck. The good thing is that at least I know where to look now.

 

Wonder why Arnott used that design. The stock design used a 12v solenoid controlled pilot exhaust valve.

 

The Arnott is also has a 12v coil. It just seems weak.

 

thats the pump I had AP 3431. He told me it was about 2k to have installed along with pass side sunroof drain. Wiped out the fuse panel. So he was in it for 4k one trip to the dealer. Leaking valve blocks burned his new pump up. Ive already fixed driver side sun roof drain and the damn cabin filter license plate trick. These rigs are sweet. People just give them away cause they are to lazy to do the work or take it hard at the dealer. Super excited to make some trips in this lr3. Been rocking a 99 4runner for like 13yrs. Feels so nice to have more comfort

 

Well worked great for about 130 miles. Ran to the grocery store and now consistently throws pressure increase too slow fault. Pulled live values. Seems to run for 8 to 10 second. Seems to be stuck at 117. When it faults, dumps galley pressure to 30. Then slowly drops from 30 to about 15. All blocks have been cleaned and new o rings. Dryer is clean and serviced. Clean all harnesses with crc spray, New compressor motor... Could I have a bad pressure sensor? Still have a leak?

 

Well it could be the pressure sensor, but keep in mind its simply resistance that provides the reading. So it could very well be a wiring issue, wires head forward to the driver wheel well. I think you may be able to cheat a little and disturb the wires while watching the live value. As for pressure during, normal. The gallery is not 100% air tight by design anyway and I think I mentioned it is intentionally dumped before a compressor startup so it is not fighting pressure to get that tiny piston going.

So maybe observe live pressure values and see if they jump around while driving or messing/tugging on the harness and go form there. What a frustrating issue! Reminds me of my fuel pump issue (was a bad wire!)

 

Cant find and bad wires. Took live values of compressor. While it is running for 10 to 15 seconds before faults I noticed zero increase of psi in gallery. Does this mean my center valve block is stuck and not allowing any air from the compressor to enter the system?

 

The center valve block does not control air flow except in/out of reservoir. Either a major leak or pressure sensor is faulty is best guess.

 

ive checked for leaks. Not a single one. Seems like the center block is stuck and zero air is coming from compressor. Sucks cause it worked flawlessly for a couple days now undrivable. Checked to see if spring was hung up in center block. It moves freely. So possible bad solenoid in block?

 

Sorry, meant reservoir. For some reason the mobile version of this site is a total joke, so I was re-typing that a few times.