The missing link: is air cleaner housing to blame for two issues?
03-27-2023, 11:54 AM
#1
The missing link: is air cleaner housing to blame for two issues?
Could a badly seated cover on the air cleaner housing have caused intermittent problems with both acceleration and air suspension?
'08 CTT, 120k mi, all stock
First, I've been getting an intermittent chassis warning about air suspension. Tough to reproduce the problem, but it happened mostly when it's trying to return to normal height after driving at a lower height (automatically after driving at 70+ mph for a while). Also, when starting, I could hear the air compressor running for a long time. I checked the level control module with my NT530 and sometimes I would see the compressor temp go really high, but again, intermittently and not clear how to reproduce. Only a chassis fault on the dash, no codes. Otherwise the car is sitting level at a normal height when the engine is running, so the compressor is able to reach normal height, but it seems to struggle getting there.
Second, I had an incident where it stranded me--I was pulling out of a parallel parking spot and as I gave it the beans the engine choked and died. I tried starting it again and same thing, choked and died. Then it wouldn't turn on at all. Called for a tow and had every manner of insult and finger thrown at me by passers by as I was blocking traffic and couldn't move. About an hour later as I was waiting, I managed to get it started and pull back into the spot, but I left the engine running this time until the tow showed up. My indy shop was only able to reproduce the problem after driving around for a while, but no codes were thrown. They said without codes they can't really diagnose the problem, but guessed that it was the HPFP and quoted me $5k to replace it.
I had the car towed home and put it on the shelf for a couple weeks. I drove it around with the NT530 showing live data of HPFP set point vs. actual value and they seemed to track normally, especially when the engine is warm, the lines are right on top of each other. If it was a faulty fuel pump, why would it suddenly start working again?
Could these issues be related? I started thinking that the issue where it stranded me might be related to the air compressor issue--maybe it's an air issue and not a fuel issue? I started poking around the air filter for any obvious issues and found that the cover on the right air filter was seated improperly at the bottom. I seated it correctly and took it out for a drive. To my surprise, all the issues disappeared! No more chassis fault and the HPFP demand/supply charts look perfect. Could this really have been the source of these two issues? I am afraid I'm putting the tow company's kids through college at this point.
References:
Air suspension issue
1. https://rennlist.com/forums/cayenne-...libration.html
2. https://rennlist.com/forums/cayenne-...n-problem.html
3. https://rennlist.com/forums/cayenne-...me-help-2.html
Fuel pump issue
1. https://rennlist.com/forums/997-foru...fuel-pump.html
2. https://dorkiphus.net/porsche/showpo...02&postcount=2
'08 CTT, 120k mi, all stock
First, I've been getting an intermittent chassis warning about air suspension. Tough to reproduce the problem, but it happened mostly when it's trying to return to normal height after driving at a lower height (automatically after driving at 70+ mph for a while). Also, when starting, I could hear the air compressor running for a long time. I checked the level control module with my NT530 and sometimes I would see the compressor temp go really high, but again, intermittently and not clear how to reproduce. Only a chassis fault on the dash, no codes. Otherwise the car is sitting level at a normal height when the engine is running, so the compressor is able to reach normal height, but it seems to struggle getting there.
Second, I had an incident where it stranded me--I was pulling out of a parallel parking spot and as I gave it the beans the engine choked and died. I tried starting it again and same thing, choked and died. Then it wouldn't turn on at all. Called for a tow and had every manner of insult and finger thrown at me by passers by as I was blocking traffic and couldn't move. About an hour later as I was waiting, I managed to get it started and pull back into the spot, but I left the engine running this time until the tow showed up. My indy shop was only able to reproduce the problem after driving around for a while, but no codes were thrown. They said without codes they can't really diagnose the problem, but guessed that it was the HPFP and quoted me $5k to replace it.
I had the car towed home and put it on the shelf for a couple weeks. I drove it around with the NT530 showing live data of HPFP set point vs. actual value and they seemed to track normally, especially when the engine is warm, the lines are right on top of each other. If it was a faulty fuel pump, why would it suddenly start working again?
Could these issues be related? I started thinking that the issue where it stranded me might be related to the air compressor issue--maybe it's an air issue and not a fuel issue? I started poking around the air filter for any obvious issues and found that the cover on the right air filter was seated improperly at the bottom. I seated it correctly and took it out for a drive. To my surprise, all the issues disappeared! No more chassis fault and the HPFP demand/supply charts look perfect. Could this really have been the source of these two issues? I am afraid I'm putting the tow company's kids through college at this point.
References:
Air suspension issue
1. https://rennlist.com/forums/cayenne-...libration.html
2. https://rennlist.com/forums/cayenne-...n-problem.html
3. https://rennlist.com/forums/cayenne-...me-help-2.html
Fuel pump issue
1. https://rennlist.com/forums/997-foru...fuel-pump.html
2. https://dorkiphus.net/porsche/showpo...02&postcount=2
03-28-2023, 08:51 AM
#2
RL Community Team
Rennlist Member
Rennlist Member
I very much doubt it and it was just a coincidence. Can't see how it would effect the air suspension as it's just a filtered inlet source for the compressor. You may have 2 different issues going on - one with fueling and one with the air suspension.
