airmatic air compressor wont run
01-27-2018, 07:35 PM
#1
Junior Member
Thread Starter
airmatic air compressor wont run
This thing has got me chasing my tail, I am pretty darn frustrated.
I bought a cheap chinese knock off compressor 6 months ago with a one year warranty... apparently the warranty is we will sell you another one at the same price. Its turning but won't put out any pressure.
so I rebuilt the old one. but I can't get the thing to turn on. It works when I bench test it. The underhood relay has 4 pins passenger side one is the the positive from the pre fuse under the passenger feet. Drivers side goes to the compressor, the tail side goes to the pressure switch on the compressor and it should be a positive. the front pin should be a ground but its open. So I don't know if the car is switching it or not.
anyhow, positive trigger to the pressure switch is intermittent when it gets power, like its on for a minute or two when you start the car. I have never gotten a negative ground on the relay port.
when I bypass the relay and put positive through the relay port to the compressor it pumps and if its not connected to the air pressure hose to the manifold block I get 125 psi (holding a spark plug compression tester on the port, so it may be able to build more pressure) but when I plug the air hose into the car, it wont lift the car and if feels like the air is going out the inlet port of the compressor.
I am so confused what is going on, the chinese compressor was just running and not pumping the original one just won't fire by itself what the heck is going on?
I like the airmatic but this all is getting super old, I just replaced the front struts also......
I bought a cheap chinese knock off compressor 6 months ago with a one year warranty... apparently the warranty is we will sell you another one at the same price. Its turning but won't put out any pressure.
so I rebuilt the old one. but I can't get the thing to turn on. It works when I bench test it. The underhood relay has 4 pins passenger side one is the the positive from the pre fuse under the passenger feet. Drivers side goes to the compressor, the tail side goes to the pressure switch on the compressor and it should be a positive. the front pin should be a ground but its open. So I don't know if the car is switching it or not.
anyhow, positive trigger to the pressure switch is intermittent when it gets power, like its on for a minute or two when you start the car. I have never gotten a negative ground on the relay port.
when I bypass the relay and put positive through the relay port to the compressor it pumps and if its not connected to the air pressure hose to the manifold block I get 125 psi (holding a spark plug compression tester on the port, so it may be able to build more pressure) but when I plug the air hose into the car, it wont lift the car and if feels like the air is going out the inlet port of the compressor.
I am so confused what is going on, the chinese compressor was just running and not pumping the original one just won't fire by itself what the heck is going on?
I like the airmatic but this all is getting super old, I just replaced the front struts also......
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eFifty5AMG (02-02-2018)
01-28-2018, 05:28 PM
#3
Junior Member
Thread Starter
Thanks Barry I looked over that whole pdf that you sent me several months ago. I think that image is the air supply.
I still don't know why I don't get power to turn the relay on. the power to the pressure switch is intermittent, is that fused somewhere. and is the ground on the relay switched somewhere also?
maybe my old compressor is only putting out 125 psi and that is not enough to make it past a check valve? the pressure releif valve is like 300psi but that seems like a lot of pressure.
I still don't know why I don't get power to turn the relay on. the power to the pressure switch is intermittent, is that fused somewhere. and is the ground on the relay switched somewhere also?
maybe my old compressor is only putting out 125 psi and that is not enough to make it past a check valve? the pressure releif valve is like 300psi but that seems like a lot of pressure.
01-31-2018, 11:09 AM
#4
Junior Member
Thread Starter
I figured this couldn't be as complicated as I was making it so I picked up a used wabco compressor installed it and it all just worked.
I have no idea why I could not get readings out the relay block and why the original wabco compressor bench tested fine. Maybe I just did enough work to appease the Mercedes Gods.
I have no idea why I could not get readings out the relay block and why the original wabco compressor bench tested fine. Maybe I just did enough work to appease the Mercedes Gods.
02-02-2018, 02:06 PM
#6
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Join Date: Apr 2017
Location: Tampa Bay, FL
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05 E55, 98 CLK320
Dude I had the SAME exact situation as you ebay warranty and everything
Here's how I solved it:
Bought a compresson on Amazon from Arnott (wabco) cheaper than their website
Problem solved. Get a new one seriously.
EDIT: I see you gots one
Here's how I solved it:
Bought a compresson on Amazon from Arnott (wabco) cheaper than their website
Problem solved. Get a new one seriously.
EDIT: I see you gots one
02-02-2018, 06:56 PM
#7
Junior Member
Thread Starter
I scored on the used one, Paid $150 it was a used but so new it wasn't even dirty with wabco sticker and ID, it was for an 09 but I just had to swap the suction tube.
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02-03-2018, 08:23 AM
#8
MBWorld Fanatic!
I'm getting the visit workshop message with the little picture of a car around an up arrow. I have a star system, but when I heard the compressor kick on it sounded so bad i didn't bother hooking it up. Found a lightly used Arnott pump on ebay from a junk yard for 170, or I guess it's a "recycling facility" these days.
