Air Ride Problems

M8SHOSCGUY

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I should be an expert.. 3 MK8's, but the blue '93 has issues. The guy before me played with the wiring likely for one of those air ride controllers, but I fixed that. I put in a verified air compressor with a great vent solenoid, height sensors. The dang thing doesn't want to vent! I exploded (Loud as HECK!) one of the front struts, and replaced that. It pumps up waaay high, doesn't stop, and doesn't vent. I replaced the suspension controller. Still no glory. I tried to do the test using an ODB1 scanner in the suspension port, but as soon as I turn on the ignition it just want's to pump high instead of the click click with a couple seconds of pump. I finally got the height useable by turning OFF the air ride as it pumps up. There is no closed loop control of the height, no leaks anywhere. If it pumps too high, I have to undo the solenoids to let it vent. I have around 5 Volts of height sensor power from the controller. Is this the right voltage?

Any ideas?

mark
 
I wonder if the relay could be bad giving power to the compressor full time? I know they usually fail off, but it could happen I guess.
 
The compressor works great.. It will shut off, but the ride is sky high when it does. It's like it's reading the height sensors way too low. I get 5V at the sensors for power. Is that the right voltage?

Any clues? Thanks for any info.

mark
 
I get 5V at the sensors for power. Is that the right voltage?

Yes.

The following measurements are made with the control module connectors in place on the module. The air suspension service switch must be ON and the ignition switch must also be ON.

The following measurements are made by backprobing the module connectors. The technician must use care to see that the wires are not damaged and that the insulation is not cut.

Height Sensor Power: Pin 28 (+) PK/W and Pin 10 (-) BK/PK = 5.0 volts.

Height Sensor Signal:
Left front: Pin 7 (+) PK/BK to Pin 10 (-) BK/PK
Right front: Pin 8 (+) T to Pin 10 (-) BK/PK
Rear: Pin 9 (+) O/BK to Pin 10 (-) BK/PK
Maximum: 4.5 volts
Minimum: 0.5 volt
Voltage should be at 2.5 volts with vehicle at normal ride height.
Voltage should fluctuate as corners are bounced.

There are several other system checks we could go through.
 
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Have you set your sensor correct in the front? Remember to lower the car you need to move the ball attachment point for the sensor up on the bracket. Just a thought
 
yeah my guess without being there lookin with you would be the Height Sensor. Is it on both sides or one side? The two fronts are seperate I think. If it's both sides, then you gotta look at the schematics for a common point.
 
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