Crazy Airmatic symptoms....Pump turns on every 2 minutes.
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Joined: Jul 2007
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Crazy Airmatic symptoms....Pump turns on every 2 minutes.
So I have a new one for everyone.
2001 S430 112K Miles
New Shocks (all 4, Arnott new)
New Air pump (Wabco OEM)
New Air pump filter (MANN)
New Air pump relay
New Valve block (OES)
I am tired of swapping out parts so I will plead my case below:
The car doesn't have a leak, I have used Star diagnostic and the system checks out. I used Autel Diagnostic tools, everything is fine, all test pass. But the pump turns on every few minutes, even while driving. Even while cruising on the freeway it turns on from time to time. I especially notice it when braking, the nose dips and at the red light the pump turns on and lift the front. Overnight the front doesn't leak at all!. The back drops about 1/4-1/2" but that's after a few days and it never drops below that. I don't know why the pump keeps turning on. When I start the car the pump turns on and lifts the car up, the thing is the car ride height is fine! So slowly as I drive it keeps going up and down. I have read the ride height sensor and they function properly. Tt is the next thing I am going to change, but I wanted to share my strange story to see if anyone else has run into something similar.
2001 S430 112K Miles
New Shocks (all 4, Arnott new)
New Air pump (Wabco OEM)
New Air pump filter (MANN)
New Air pump relay
New Valve block (OES)
I am tired of swapping out parts so I will plead my case below:
The car doesn't have a leak, I have used Star diagnostic and the system checks out. I used Autel Diagnostic tools, everything is fine, all test pass. But the pump turns on every few minutes, even while driving. Even while cruising on the freeway it turns on from time to time. I especially notice it when braking, the nose dips and at the red light the pump turns on and lift the front. Overnight the front doesn't leak at all!. The back drops about 1/4-1/2" but that's after a few days and it never drops below that. I don't know why the pump keeps turning on. When I start the car the pump turns on and lifts the car up, the thing is the car ride height is fine! So slowly as I drive it keeps going up and down. I have read the ride height sensor and they function properly. Tt is the next thing I am going to change, but I wanted to share my strange story to see if anyone else has run into something similar.
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'11 E350, '11 E550, '98 M3, '95 E320
Based on what I've seen in our W212s, the airmatic runs ~ 10s for every driven mile... so more than one would "think". With Star, someone can monitor while you drive, checking for target height, current height and get a sense of what going on. Another feature, at least on the W212s, is the suspension will lower over a certain speed (freeway) and then raise when you slow down.
I would take note the compressor time and then drive for a week or so... then figure the ON time by mileage.
I would take note the compressor time and then drive for a week or so... then figure the ON time by mileage.
Thread Starter
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Joined: Jul 2007
Posts: 5
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Backstory:
When I got it from the previous owner the rear was on the floor, he had put used shocks and they blew out on him and he sold the car to me. When I got it (dirt cheap
) I changed all 4 shocks immediatly and I started to notice the pump started having those issues. After a week I changed the pump, relay and valve block, still the same symptoms.
Riding with Star is a good idea, thank you. I do understand the pump needs to periodically turn on, but for sure not this much. I have been in many w220s and never have I noticed a pump turn on this much. Its almost every red light, or every couple minutes when just parked, every morning when I start. Freeway ever few minutes. I feel like it keeps correcting itself and the ride height tolerances came down to almost nothing. I.E. too high now lower, oh too low now raise, wait too high drop, etc etc.
When I got it from the previous owner the rear was on the floor, he had put used shocks and they blew out on him and he sold the car to me. When I got it (dirt cheap
) I changed all 4 shocks immediatly and I started to notice the pump started having those issues. After a week I changed the pump, relay and valve block, still the same symptoms. Based on what I've seen in our W212s, the airmatic runs ~ 10s for every driven mile... so more than one would "think". With Star, someone can monitor while you drive, checking for target height, current height and get a sense of what going on. Another feature, at least on the W212s, is the suspension will lower over a certain speed (freeway) and then raise when you slow down.
I would take note the compressor time and then drive for a week or so... then figure the ON time by mileage.
I would take note the compressor time and then drive for a week or so... then figure the ON time by mileage.
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Joined: May 2015
Posts: 4,037
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From: Miami, FL
2003 CL 600
But what's the harm in the pump running a little bit like that all the time? As long as it isn't staying on for 2 minutes straight, it's not gonna hurt anything. That system doesn't have a reservoir so the pump has to run for every correction, which as you say is happening every time there is a change in the car. Not really abnormal as long as it's holding pressure overnight. You could have a valve block not sealing fully when driving, but I would assume if that was the case it would leak down at times when parked for more than a couple hours.
Newbie
Joined: Nov 2024
Posts: 13
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From: SC
2017 GLS450
Backstory:
When I got it from the previous owner the rear was on the floor, he had put used shocks and they blew out on him and he sold the car to me. When I got it (dirt cheap) I changed all 4 shocks immediatly and I started to notice the pump started having those issues. After a week I changed the pump, relay and valve block, still the same symptoms.
Riding with Star is a good idea, thank you. I do understand the pump needs to periodically turn on, but for sure not this much. I have been in many w220s and never have I noticed a pump turn on this much. Its almost every red light, or every couple minutes when just parked, every morning when I start. Freeway ever few minutes. I feel like it keeps correcting itself and the ride height tolerances came down to almost nothing. I.E. too high now lower, oh too low now raise, wait too high drop, etc etc.
When I got it from the previous owner the rear was on the floor, he had put used shocks and they blew out on him and he sold the car to me. When I got it (dirt cheap
) I changed all 4 shocks immediatly and I started to notice the pump started having those issues. After a week I changed the pump, relay and valve block, still the same symptoms.Riding with Star is a good idea, thank you. I do understand the pump needs to periodically turn on, but for sure not this much. I have been in many w220s and never have I noticed a pump turn on this much. Its almost every red light, or every couple minutes when just parked, every morning when I start. Freeway ever few minutes. I feel like it keeps correcting itself and the ride height tolerances came down to almost nothing. I.E. too high now lower, oh too low now raise, wait too high drop, etc etc.
If you didn't find an "issue," did your compressor bomb from the excessive running or has it held up, supporting the other theory that it is more normal than we thought?
Thanks!
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Member
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Posts: 78
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S55
Old post, I know, but desperately trying to figure out the same thing. Did you ever get anywhere with your investigation? Car does not leak anywhere that causes it to sag nor do level sensors change when parked for days. Lifted or normal height, I've checked both. As soon as it's driving, seems to cut compressor on every couple of minutes, verified by watching live data on compressor run time while driving.
If you didn't find an "issue," did your compressor bomb from the excessive running or has it held up, supporting the other theory that it is more normal than we thought?
Thanks!
Edit
If you didn't find an "issue," did your compressor bomb from the excessive running or has it held up, supporting the other theory that it is more normal than we thought?
Thanks!
Edit
I'm not sure if it's related, but had bad pressure valve( I think it's called differently) it's located on compressor. Also replaced piston ring while compressor was out on table. Mine was working way more than it's designed, would say every 15min, and run time was about 30sec.
Strongly suggest to check for any codes in unit.
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Newbie
Joined: Nov 2024
Posts: 13
Likes: 0
From: SC
2017 GLS450
Hey, did you try to check for codes?
I'm not sure if it's related, but had bad pressure valve( I think it's called differently) it's located on compressor. Also replaced piston ring while compressor was out on table. Mine was working way more than it's designed, would say every 15min, and run time was about 30sec.
Strongly suggest to check for any codes in unit.
I'm not sure if it's related, but had bad pressure valve( I think it's called differently) it's located on compressor. Also replaced piston ring while compressor was out on table. Mine was working way more than it's designed, would say every 15min, and run time was about 30sec.
Strongly suggest to check for any codes in unit.
Thanks for following up, I greatly appreciate you doing so and I appreciate all I've learned from this forum!
Super Member
Joined: Jun 2018
Posts: 533
Likes: 39
From: Northern Hemisphere - Chicago
fleet
i had this once
do you have any ambiguity about the electrical connector at the front struts? each one has one
turned out to be the airmatic electrical plug, i had to zip tie it to make it tight. it also has a grommet at the wheel well for wire slack if that makes sense
do you have any ambiguity about the electrical connector at the front struts? each one has one
turned out to be the airmatic electrical plug, i had to zip tie it to make it tight. it also has a grommet at the wheel well for wire slack if that makes sense
Last edited by e350forme; Nov 18, 2024 at 03:42 PM.
Newbie
Joined: Nov 2024
Posts: 13
Likes: 0
From: SC
2017 GLS450
i had this once
do you have any ambiguity about the electrical connector at the front struts? each one has one
turned out to be the airmatic electrical plug, i had to zip tie it to make it tight. it also has a grommet at the wheel well for wire slack if that makes sense
when my plugs were seated all the way the scanner registered everything but then the code never went away and ride height all wonky. ride height changed when new shocks went in
i cant believe you got all those nice parts so pricey i used the ebay struts
there is a 247 w220 live chat on IG, its called w200 dash light mafia you should join it
do you have any ambiguity about the electrical connector at the front struts? each one has one
turned out to be the airmatic electrical plug, i had to zip tie it to make it tight. it also has a grommet at the wheel well for wire slack if that makes sense
when my plugs were seated all the way the scanner registered everything but then the code never went away and ride height all wonky. ride height changed when new shocks went in
i cant believe you got all those nice parts so pricey i used the ebay struts
there is a 247 w220 live chat on IG, its called w200 dash light mafia you should join it
Super Member
Joined: Jun 2018
Posts: 533
Likes: 39
From: Northern Hemisphere - Chicago
fleet
to be honest my compressor is the same, loud and on "often" (less often than not through)... seems to be happy honestly, original pump,(i wish i had a spare just incase, but probably hard to replace i haven't looked into it luckily) . obviously if something is wonky it will be all confused
my pump turns on LESS when i am driving
my pump turns on LESS when i am driving
Last edited by e350forme; Nov 18, 2024 at 03:42 PM.
Super Member
Joined: Jun 2018
Posts: 533
Likes: 39
From: Northern Hemisphere - Chicago
fleet
Thanks for following up! Yes, I ran codes, nothing persistent or repetitive. Ran active tests on every system and nothing threw an error, all checked out. Car doesn't sag at all. Compressor just kicks in every couple minutes for no apparent reason. Replaced valve block, same thing. Finally put new compressor in it this week (pressure relief valve you mentioned was saturated/wet on old one and it was getting loud from wear). Same problem existed with new compressor, but miraculously, after asking today, it hasn't kicked on like it was. I raised the car this morning and let it sit for 6-7 hours before this afternoon's drive. No clue what the gremlin is/was at this point because the new compressor was doing same thing until this afternoon when I drove it for a little over a half hour.
Thanks for following up, I greatly appreciate you doing so and I appreciate all I've learned from this forum!
Thanks for following up, I greatly appreciate you doing so and I appreciate all I've learned from this forum!
w220 dash light
they got every smart guy on demand for the w220 willing to help out and chat at anytime
Newbie
Joined: Nov 2024
Posts: 13
Likes: 0
From: SC
2017 GLS450
to be honest my compressor is the same, loud and on "often" (less often than not through)... seems to be happy honestly, original pump,(i wish i had a spare just incase, but probably hard to replace i haven't looked into it luckily) . obviously if something is wonky it will be all confused
my pump turns on LESS when i am driving
my pump turns on LESS when i am driving
MBWorld Fanatic!
Joined: Dec 2012
Posts: 2,473
Likes: 439
From: Ball Ground, GA (N of Atlanta)
2003 S500 2007 GL450
The most difficult part of replacing the Airmatic compressor is keeping track of the parts and correct assembly of the compressor mounting system. It isn't intuitively obvious at all.
Failure or incorrect assembly of the mounting system is also one of the most common causes of noisy compressor operation.
If the compressor runs more than usual, it is very likely that a $10 piston ring will help the situation.
Failure or incorrect assembly of the mounting system is also one of the most common causes of noisy compressor operation.
If the compressor runs more than usual, it is very likely that a $10 piston ring will help the situation.
Super Member
Joined: Jun 2018
Posts: 533
Likes: 39
From: Northern Hemisphere - Chicago
fleet
The most difficult part of replacing the Airmatic compressor is keeping track of the parts and correct assembly of the compressor mounting system. It isn't intuitively obvious at all.
Failure or incorrect assembly of the mounting system is also one of the most common causes of noisy compressor operation.
If the compressor runs more than usual, it is very likely that a $10 piston ring will help the situation.
Failure or incorrect assembly of the mounting system is also one of the most common causes of noisy compressor operation.
If the compressor runs more than usual, it is very likely that a $10 piston ring will help the situation.
