2003 Town Car,Air suspension pumps air every time i turn on engine ?

klein2005

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Hello, i replaced the both air springs on December/15/2018, now i have a problem, every time i start the car , air pump kick in , only for 5-6 seconds,even i go in store for 1 minute and come back turn on the car , air pump will kick it again,i think 90% of time ,the air pump will kick in .but i don't hear pump kick in during i'm driving on the road,pump only kick in only when i start the car,i think with old air springs , it only pumps air only one time in the morning,so do i have a leak? im not sure if because of this ..... few days after u replaced new air springs,my car break down on freeway,my car was tow back to my house,is it possible when the tow truck driver holds my car on his truck too hard? that's how my air springs got damaged ? thank you


PS, one day i wanna check my engine,i start my car in garage,pump kicks in for 6-7 seconds, i back my car to my drive way ,and turn off car,i open the engine hood,i hear the hiss of the air escaping around air filter area, i know air pump is under air filter.is it possible something wrong around air pump? air horse ?solenoid ?
 

wolf_walker

Junior Member
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If it isn't sagged down badly after sitting overnight, you likely don't have a leak. Running on first start of the day isn't unusual, or even after running into the store or such. There are many factors that go into the system deciding to run the pump.
 

All2kool

Senior Member
1,177
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38
Portland, OR
It's supposed too after having sat parked for more than about 20 minutes as the system releases or vents the pressure. Be concerned when it fails to occur. If yours is running every time you start the car, even if you start the car 3 times in a row, then you may have an issue.
 

Town

Senior Member
4,398
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Ottawa Ontario Canada
The air suspension system will not adjust the ride height while driving unless the height sensor determins a high or low suspension reading for a continuous 45 seconds. This is to avoid constant height changes due to normal dynamic suspension height changes due to road changes.

It is normal for the suspension to lower after an hour or so after being parked. It then airs up when the ignition is turned on in the "morning". It should then stay at that trim height for the rest of the day unless weight is added or removed from the car.

The air suspension adjusts quickly to height sensor changes when car is stationary as in a parked condition. When parked and doors closed (suspension will not vent while doors are open) the module will adjust the suspension height according to the height sensor reading to get to trim height. So when you park the car for a minute or two and return to the car and turn on the ignition the module checks the height sensor for trim height and should not need to take any action. If the module detects the height sensor at above or below trim height after a short time it will vent or raise the suspension. So in this case there is a leak or the height sensor is not working correctly.

With new air springs the most likely leak is from the air spring solenoid O ring that seals the solenoid to the spring housing. Usually the O ring is replaced with a new one and lubricated. It is unlikely the height sensor is a problem since the lever type on your car is more resistant to issues than the older type. To check for a leak at the air spring solenoids turn off the suspension switch then jack and support the rear of the car and spray soapy water solution in the area of the solenoid and look for bubbles. To be sure spray the entire spring rubber membrane in case it got punctured somehow. There should not be any cracks in the rubber.

When your car was towed the suspension switch in the trunk should have been turned off. If it was not then the suspension would vent because the height sensor would be extended. When the car was then lowered the rear suspension would collapse to the ground. When the ignition is turned on the suspension would raise almost always. There would be the possibility that the air path into the spring would be blocked in which case the rear of the car would need to be jacked up a little to allow air into the air springs.

The air release noise near the air filter would be the vent solenoid in the compressor releasing air from the air springs to lower the suspension. That vent solenoid is operated by the suspension module because the height sensor is above trim height for the hour after parking. After that hour it is the venting to lower suspension for prolonged parking. Car usually lowers about an inch when measured from ground to underside of rear wheel arch.

Hope this helps
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klein2005

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The air suspension system will not adjust the ride height while driving unless the height sensor determins a high or low suspension reading for a continuous 45 seconds. This is to avoid constant height changes due to normal dynamic suspension height changes due to road changes.

It is normal for the suspension to lower after an hour or so after being parked. It then airs up when the ignition is turned on in the "morning". It should then stay at that trim height for the rest of the day unless weight is added or removed from the car.

The air suspension adjusts quickly to height sensor changes when car is stationary as in a parked condition. When parked and doors closed (suspension will not vent while doors are open) the module will adjust the suspension height according to the height sensor reading to get to trim height. So when you park the car for a minute or two and return to the car and turn on the ignition the module checks the height sensor for trim height and should not need to take any action. If the module detects the height sensor at above or below trim height after a short time it will vent or raise the suspension. So in this case there is a leak or the height sensor is not working correctly.

With new air springs the most likely leak is from the air spring solenoid O ring that seals the solenoid to the spring housing. Usually the O ring is replaced with a new one and lubricated. It is unlikely the height sensor is a problem since the lever type on your car is more resistant to issues than the older type. To check for a leak at the air spring solenoids turn off the suspension switch then jack and support the rear of the car and spray soapy water solution in the area of the solenoid and look for bubbles. To be sure spray the entire spring rubber membrane in case it got punctured somehow. There should not be any cracks in the rubber.

When your car was towed the suspension switch in the trunk should have been turned off. If it was not then the suspension would vent because the height sensor would be extended. When the car was then lowered the rear suspension would collapse to the ground. When the ignition is turned on the suspension would raise almost always. There would be the possibility that the air path into the spring would be blocked in which case the rear of the car would need to be jacked up a little to allow air into the air springs.

The air release noise near the air filter would be the vent solenoid in the compressor releasing air from the air springs to lower the suspension. That vent solenoid is operated by the suspension module because the height sensor is above trim height for the hour after parking. After that hour it is the venting to lower suspension for prolonged parking. Car usually lowers about an inch when measured from ground to underside of rear wheel arch.

Hope this helps
Hello Sir,

when i go to stores, in and out is only few minutes,i dont add weight to the car or take off weight,but it still pimps air everytime i start engine.after i park car in garage, the ride height is 75.5cm, next day is 74.5cm,so i assume no leaks in new air bags,otherwise over night the car will sit on the ground.and i also assume the ride height sensor is working properly,otherwise the car wont stay in 75.5cm everytime i come back to garage.so by your point of view,u think i might have small leaks on solenoids of 2 air bags right? and i also DID replace the new three O rings with new air bags,i only didnt replace the small O ring on air line, so my car doesnt suppose to pump everytime i start the car in a single day right?
 

klein2005

New member
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It's supposed too after having sat parked for more than about 20 minutes as the system releases or vents the pressure. Be concerned when it fails to occur. If yours is running every time you start the car, even if you start the car 3 times in a row, then you may have an issue.
so what kind of issue would it be ?
 

klein2005

New member
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If it isn't sagged down badly after sitting overnight, you likely don't have a leak. Running on first start of the day isn't unusual, or even after running into the store or such. There are many factors that go into the system deciding to run the pump.
i remember before i replaced the new air bags , it didn't pump everytime i start engine in one day!maybe only one time in the morning. so what kind of problem u think is it ?
 

Town

Senior Member
4,398
121
63
Ottawa Ontario Canada
Hello Sir,

when i go to stores, in and out is only few minutes,i dont add weight to the car or take off weight,but it still pimps air everytime i start engine.after i park car in garage, the ride height is 75.5cm, next day is 74.5cm,so i assume no leaks in new air bags,otherwise over night the car will sit on the ground.and i also assume the ride height sensor is working properly,otherwise the car wont stay in 75.5cm everytime i come back to garage.so by your point of view,u think i might have small leaks on solenoids of 2 air bags right? and i also DID replace the new three O rings with new air bags,i only didnt replace the small O ring on air line, so my car doesnt suppose to pump everytime i start the car in a single day right?
Your car is not supposed to need air in the springs every time you stop for a few minutes, but stopping on an uneven surface may put more weight on rear axle and so lower the rear suspension and cause it to air up when ignition turned on. Ideally you would have replaced the air spring solenoids with the air springs so that o ring would be replaced automatically.

A drop of 1 cm is less than I would expect for a normal overnight venting. That would suggest that you don't have a leak. But the first step in my opinion is to check for leaks on the entire air springs and solenoids and rule the leak out for sure.

If you don't have a leak then the height sensor or the suspension module would be suspect. But that would be quite the co-incidence after the problem started with the new air springs and solenoids.
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wolf_walker

Junior Member
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i remember before i replaced the new air bags , it didn't pump everytime i start engine in one day!maybe only one time in the morning. so what kind of problem u think is it ?
I don't think it's a problem at all if the system isn't sinking down overnight.
Many people report different behaviors of these system with no obvious faults in them. My conclusion has been that
there is either more going on than just reading a target voltage in the ECU that controls it, or like Town said
there is enough variance in the parking area to trigger the pump since the sensor only reads the drivers side.
You could test it if you wanted by finding a very flat area and marking exactly where to stop and doing so a couple times,
preferably while watching the voltage from the height sensor.

It's possible, though I've never heard of it, that the height sensor is wearing right around it's normal operating position, the same way
and old throttle position sensor would get a "fuzzy" spot you'd check with a graphing multimeter or even a volume knob on an old radio
would have a noisy spot, but it seems unlikely. Remember also that the car lowers after you get out(removing your weight), so if you pull up it's leveled itself to wherever you started from not where you parked at, until you turn the key again.

Just a few weeks ago, I was starting to think mine was broken as I'd not heard the pump run in a few weeks, which is only about five
or six outings for me. So I actually got a couple people to sit in the back seat and make sure it came on, and all was indeed well.
Generally after sitting a few days it will run briefly even with just me in the car (175lbs) but for whatever reason, weather, lunar
cycle, etc, not those weeks. And it's always parked in the same spot. Go figure.
My general rule of thumb now is if it's not sagging overnight, and if the pump isn't running while you're driving around or
for more than eight or ten seconds max on startup without load, it's good enough.
 

99siggy

New member
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Houston, TX
i remember before i replaced the new air bags , it didn't pump everytime i start engine in one day!maybe only one time in the morning. so what kind of problem u think is it ?
This is where you should start to help solving this problem; turn OFF the Air Suspension Switch over night and see if your Town Car loses air and is lower the next morning. Then post back here.
 

klein2005

New member
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0
1
This is where you should start to help solving this problem; turn OFF the Air Suspension Switch over night and see if your Town Car loses air and is lower the next morning. Then post back here.
Hello Sir,

yesterday 5pm after i came home, ride height was 29.5cm (29 3/4 inches),i turned off air Suspension Switch,and today 2pm (21 hours later),it's 28.3 cm (29 1/4 inches).thank you
 

wolf_walker

Junior Member
97
11
8
When you checked the ride height was that before or after it had vented down once you got out of the car?
Was there a great temp difference between the bag temp (remember how hot an air compressor gets when filling up, compressed air is friction heated) after driving and after sitting 21hrs?

If I was doing this test, I would let it sit another 20someting hours after establishing a cold temp height with the system off,
and check it again when the temp is pretty near the same. Removing variables is the name of the game when you're
dealing with small changes.

I don't think you have a practical problem still but if it bothers you, it bothers you, and you could certainly get a bottle of soapy water
and spend some time under the car hunting leaks at joint points or in the bags, if it pumps back up swiftly I'd leave it be.
That pump is not as fragile as everyone seems to think, the book listed safety cutout is several minutes of continuous running, few
dozen seconds here and there isn't going to shorten its lifespan appreciably I don't think.
I also think precision beyond a certain reasonable point is an unrealistic expectation for such a rudimentary
leveling system. Remember this is straight up 80's technology, it has changed very little since at least the 1990
model and I believe it was offered before.
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