Check suspension light. Help!!!!!!

[surfaaron]

On my way to work my suspension light came on. I have a 87 Mark 7. I went back home and took my van to work so I have not been able to look at anything yet. Were should I start. Give it to me in newbie terminolagy. Thanks for any info. :slam

 

[Sifrino3]

Well, when you get home and either the front or back is sitting on the ground. Jack up what side is on the ground. Just to ride height. Put the car into start. To let the front/rear fill up. (ez'r on the pump if you jack it up.) The turn off the suspention/key. Jack up one side. Take off tire. Check for leaks with soapy water.

If that is not your problem. It may be the pump. Which you can see if its the problem when you turn the key to the ON position. If it starts, its running. Doesn't mean its not the problem. Could be a leaky dryer. The plastic thing with the hoses coming from the top. May be cover with a plastic cover.

 

[JoshMcMadMac]

Here is a link to information on the air suspension: http://lsc-ss.com/lscss_site/Tech_Info/suspensionair.pdf
It is in .pdf format, so be sure to have Adobe Acrobat Reader. The instructions for the self-diagnostic test begin on about page 5. The air suspension has a built-in feature to tell you what is wrong, so it is best to use it.

If the light came on and you do not notice any abnormal ride height, I would question the compressor or dryer. What is the condition of your system? Have you made any recent changes to the air ride, or even the car in general?

After running the self-diagnostic, let us know what it tells you. Also, get the car to the proper trim height by letting it air up, then turn the car off as well as the air suspension switch in the trunk. Let it sit over night, and if you notice any considerable change in the height of any corner, you most likely have a bad bag.

If you have a pressure gauge that will read about 150psi, you can also check the compressor yourself. There is a schrader valve on the compressor that you can take a measurement from. Turn the car on and get a reading. If it is below ~120psi or close to it, your compressor is probably weak.

There are many problems that could be causing this, but most of them are inexpensive to fix. Just be patient and find the problem; don't just throw parts at it. Also, please do not ever crawl under your car if you fear it may have faulty bag(s). Be sure to have a jackstand under the frame, just in case. If that bag decides to fail with you under the car, you are going to fail with it.

 

[surfaaron]

Here is a link to information on the air suspension: http://lsc-ss.com/lscss_site/Tech_Info/suspensionair.pdf
It is in .pdf format, so be sure to have Adobe Acrobat Reader. The instructions for the self-diagnostic test begin on about page 5. The air suspension has a built-in feature to tell you what is wrong, so it is best to use it.

If the light came on and you do not notice any abnormal ride height, I would question the compressor or dryer. What is the condition of your system? Have you made any recent changes to the air ride, or even the car in general?

After running the self-diagnostic, let us know what it tells you. Also, get the car to the proper trim height by letting it air up, then turn the car off as well as the air suspension switch in the trunk. Let it sit over night, and if you notice any considerable change in the height of any corner, you most likely have a bad bag.

If you have a pressure gauge that will read about 150psi, you can also check the compressor yourself. There is a schrader valve on the compressor that you can take a measurement from. Turn the car on and get a reading. If it is below ~120psi or close to it, your compressor is probably weak.

There are many problems that could be causing this, but most of them are inexpensive to fix. Just be patient and find the problem; don't just throw parts at it. Also, please do not ever crawl under your car if you fear it may have faulty bag(s). Be sure to have a jackstand under the frame, just in case. If that bag decides to fail with you under the car, you are going to fail with it.

Thank you sooooo much for all the info . I will give it a try tonight and get back to you with what I find. Any special tools that I will need to do the tests. Thanks again for your help. I am sure I will be able to figure it out with a little help from the pros(you guys). :yourock: :headbang:

 

[JoshMcMadMac]

Any special tools that I will need to do the tests.

You will need to be able to ground the pigtail off of the suspension computer. That may require wire strippers, a length of wire, and a few connectors. Other than that the entire process is tool free. When it comes time to start fixing problems, you will need some wrenches; but we are not there, yet.

 

[surfaaron]

Thank you again. I am sure I have all the tools I will need to do the job. I was wondering more about the electrical testing. I will let you know what I find out. I am going to start with your first suggestions and then move on to the System check.

 

[surfaaron]

Found some leaks.

I found some O rings that were leaking. The dryer and the air hoses out of it were leaking. I replaced the O rings and It seems allright. Would these problems make the light go on. Also what would make it sit a little off. My passenger side back is off by about 1/2 inch. Any ideas

 

[JoshMcMadMac]

I found some O rings that were leaking. The dryer and the air hoses out of it were leaking. I replaced the O rings and It seems allright. Would these problems make the light go on. Also what would make it sit a little off. My passenger side back is off by about 1/2 inch. Any ideas

Sorry for not telling you that the o-rings were most likely your problem. I suspected this would be your issue, but did not want to blind you from other possibilities. It is best for you to troubleshoot it yourself so that there is no question about the actual source of the problem. I hope you understand.

The o-rings that go in the dryer are #6 in size. What happens is that as you drive the compressor engages to fill the bags and raise the suspension. This should always be the case, as the car will never become lighter when you add your weight to it and drive off. So, as the compressor runs, more air is leaking out of the dryer than is being added to the bags. This is typically only true for the front end, as the rear has much less weight on it and tends to retain enough air. So, as you drive along the front end will gradually become lower and lower to the ground. After the car is driven long enough for the air suspension computer to realize that the front end is not raising to trim height it shuts off, and thus registers the check light. This is what you have experienced.

I suggest that you pull all four of the orange collets and dispose of the old o-rings. Then take 2 #6 o-rings and install them in each collet. This will prevent any more leaking. Some individuals claim that this will cause issues with removing the air lines at a later date, but this was not an issue I have faced. If you prefer, try the double o-ring setup on one collet, reinstall the air line, and see for yourself. If you feel that there is no way to get the air line back out, do not double o-ring anymore. I had no problem removing them with a screwdriver and needle-nose pliers when double o-ringed. Replacing all four of the old dryer o-rings should set your car back to the proper ride height and prevent the light from coming back on. If you drive the car for a few days and notice that the ride height is still not correct on both sides you can adjust the height sensors to compensate. Just remember that the car is not going to sit perfectly level right after you get out. Remember that your butt adds weight to one side, and it can take up to an hour for the air ride to completely adjust back to proper trim height. Also remember that it is not wise to alter the ride height of the suspension if the bags are aged. This can accelerate wear and cause a leak in the bag(s).

I am glad that you had a relatively inexpensive fix, and that you found it quickly. I hope this has answered all of your questions. Good luck!

 

[surfaaron]

I did replace the o rings for the air lines but I just did single o's. I also replaced the one at the base of the dryer also. Are there any other O rings that I should just go ahead and replace(solenoids ect) or should I just wait for them to fail. I appreciate you not telling me about the o rings because I would not have looked any were else. Also will a factory repair manual for a 89 mark 7 work for my 87. Thank you again for all the help. I am sure this is just the beginning.

 

[JoshMcMadMac]

I did replace the o rings for the air lines but I just did single o's. I also replaced the one at the base of the dryer also. Are there any other O rings that I should just go ahead and replace(solenoids ect) or should I just wait for them to fail. I appreciate you not telling me about the o rings because I would not have looked any were else. Also will a factory repair manual for a 89 mark 7 work for my 87. Thank you again for all the help. I am sure this is just the beginning.

The o-ring at the base of the dryer is size #36. Be sure to use a silicone spray on the o-rings before installation. Solenoid o-rings tend to last quite some time. I would not worry about replacing them at this time. Also, I am glad that you understand why I did not mention the o-rings. That makes things easier.

A 1989 manual will work in many instances. I know there will be differences, but many of the major parts will work for your application. There are two major differences that I can think of. First, you may have the 200hp E6 head version of the 5.0L engine. This may or may not change anything in the manual. Also, if I recall properly, 1987 had stand-alone cruise control. Other than that there is nothing I can think of. But then again there are many things that allude me, so I might be overlooking something.