AHC rough ride, with readouts from ecu (1 Viewer)

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Joined
Jan 26, 2018
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14
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161
Location
San Diego
Graduation test shows only 8 bars, the fluid has 20k miles on it, rear springs are OEM from 1999 and torsion bars have never been cranked. The ride has been getting significantly harsher in the last 15k miles and I have No leaks anywhere on the system (struts, accumulators and globes, pump) leading me to believe that my globes are bad and I need to crank my TB's and replace my rear springs and replace the globes at the same time. ALSO L to N to H only takes around 17 seconds each to go up and less than 4 to go down so I think the pump and accumulators are good still.

The attached images show all the information I was able to get, first letter shows height L N H and second letter shows stiffness either Comfort or Sport

  1. Should I crank TB's now and tune it once I replace parts or just wait
  2. New rear springs or no?


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I dont know how to make the images smaller, I was trying to attach links sorry
 
Just an image of the results you get raising from L to N on flat ground will do. Comfort setting doesn’t matter but extra weight in the vehicle and actual vehicle heights measured hub center to fender bottom do matter.
If I’m reading what you’ve got correctly it looks like 10.7 and 8.4MPa which are very high - easy torsion bar adjustments now will make the front damping better and new coils/spacers will lower the rear. You will probably gain an additional graduation in your L to H check with neutral pressures closer to where they should be which will help you get the most out of your aging damper globes.
 
Just an image of the results you get raising from L to N on flat ground will do. Comfort setting doesn’t matter but extra weight in the vehicle and actual vehicle heights measured hub center to fender bottom do matter.
If I’m reading what you’ve got correctly it looks like 10.7 and 8.4MPa which are very high - easy torsion bar adjustments now will make the front damping better and new coils/spacers will lower the rear. You will probably gain an additional graduation in your L to H check with neutral pressures closer to where they should be which will help you get the most out of your aging damper globes.
Current plan is new rear springs, then cross-level and take new readings, most likely replace globes after that cause they are probably shot
 
Added 11 turns to the drivers side and 5 to the passenger side and wow, ride quality is WAY better and these are my readings, new springs will be here soon hopefully and ill be able to re cross-level and most likely not have to replace globes!

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Just an image of the results you get raising from L to N on flat ground will do. Comfort setting doesn’t matter but extra weight in the vehicle and actual vehicle heights measured hub center to fender bottom do matter.
If I’m reading what you’ve got correctly it looks like 10.7 and 8.4MPa which are very high - easy torsion bar adjustments now will make the front damping better and new coils/spacers will lower the rear. You will probably gain an additional graduation in your L to H check with neutral pressures closer to where they should be which will help you get the most out of your aging damper globes.
I put new rear springs in and the ride is much softer even though the pressure looks to be about the same, my graduation test was at 7 when I started all of this and now I am at 12
Only problem I think I see is that the vehicle is sitting completely level where typically the front end is lower than the back. I think I'm going to back off the passenger's torsion bar to bring the passenger Corner down a little bit and hopefully lower the entire front end so that there is more of a rake like there is supposed to be as long as my pressure stays within spec

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to adjust the rake of the car, you need to adjust the sensors, not the tension bars.
I would start by adjusting the front ones so both are showing close to 0. then you can increase the rear a bit and the AHC will rise abit the back to give you rake.
 
These are my readings going from l2n after adding two more clockwise turns on my driver side, the front end is level and City from Hub 2 Fender at 19.25 in and the rear is sitting at 20.5 in, I am just going to leave it because if I keep messing with that I might make it worse and leaning forward one quarter of an inch doesn't seem that bad

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What device are you using to read pressures? I just ordered the icarsoft device. I’m reading close to your numbers.
 
With the rear springs when changing them do you have to replace them with AHC ones alike or normal can do.
 
With the rear springs when changing them do you have to replace them with AHC ones alike or normal can do.
the rear springs are specific to the AHC system but you can go stiffer to help with heavy loads
 
LX was parked for a week and my pressures went back down to normal and the ride quality was much better, drove it for about an hour and my pressure is went back up to being too high again any ideas? The ride was really smooth at first but progressively got worse.... I'm going to order new Globes and flush the fluid. Graduation test is currently 14

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Im going to order new globes and fluid
 
more likely torison bars are weak and need replacing seems like globes are doing their jobs.
 
more likely torison bars are weak and need replacing seems like globes are doing their jobs.
hmm, Im not sure TB's would get better after sitting for a week but then get worse after being driven a few hours, but nitrogen from a blown globe getting remixed into the ahc fluid after sitting a week and settling at the highest point (parked on a hill with the nose up) seems pretty likely
 
hmm, Im not sure TB's would get better after sitting for a week but then get worse after being driven a few hours, but nitrogen from a blown globe getting remixed into the ahc fluid after sitting a week and settling at the highest point (parked on a hill with the nose up) seems pretty likely

The torsion bars are what support the vehicle weight if your pressures go back up its because the torsion bars are weak. Maybe i didn't understand what you are writing but @PADDO will be able to guide you.
 
Side-Question: What is that program/setup you're using to get the AHC pressures?
Doesn't look like Techstream.

Thanks!
 

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