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AHC and Torsion bars
- Thread starter arnonmg
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BobMurphy
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If you have AHC as standard you will have softer front torsion bars and rear springs than those fitted to the non-AHC vehicles. This is to allow the pressurised struts to adjust the ride height. The struts take a lot of the suspension load.
If you replace the front Torsion Bars with those from a non-AHC vehicle (as per the 'AHC Removal kit' sold by Roughtrax) I guess you won't be able to lower the suspension at the front and the struts may struggle to raise the front much.
I assume by 'OME' you mean 'Old Man Emu' rather than 'Original Manufacturer's Equipment' - which would be a pair of soft torsion bars in your case
.
You could try adjusting the ride height sensors on the front suspension to get the front to ride higher with your current set-up.
Also, the four pressurised 'globes' allow the struts to move with the suspension loads. They can lose their pressure over time and cause the suspension to feel over soft. It might be worth checking them out with a specialist Co.
Bob.
If you replace the front Torsion Bars with those from a non-AHC vehicle (as per the 'AHC Removal kit' sold by Roughtrax) I guess you won't be able to lower the suspension at the front and the struts may struggle to raise the front much.
I assume by 'OME' you mean 'Old Man Emu' rather than 'Original Manufacturer's Equipment' - which would be a pair of soft torsion bars in your case
.You could try adjusting the ride height sensors on the front suspension to get the front to ride higher with your current set-up.
Also, the four pressurised 'globes' allow the struts to move with the suspension loads. They can lose their pressure over time and cause the suspension to feel over soft. It might be worth checking them out with a specialist Co.
Bob.
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If you put in front springs which are designed to carry the whole load of the front, you will loose all damping, i.e. no shock absorber function. The 16 step adjustable damper (aka Actuator) requires a certain pressure and movement of fluid in order to work.
Having the specified AHC pressure helps though, and having the left-right balanced, both when it comes to actual height and sensor reading.
And, btw, if the gas globes loose some pressure, the suspension will be harder, not softer. The AHC pump will keep the pressure up to keep the set height, and when the globe looses gas pressure, the membrane will start to bottom out. (When the globes are completely shot, you will have no suspension at all, just four stiff struts, but still full height control)
arnonmg
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Yes Bob OME = old man...
One point that need clarification -
I assume Globes=Actuators ?
Are they work as accumulator??
If they are kind of accumulators and their membrane wears off then the pump should show some warning like high temp
Since AHC link to VSC / TRC I assume there will be other warnings as well - do you know what will be the default warnings for imbalance between struts ?
Warning for pump?
Really Appreciate your comments,
Still looking for specialist in Israel ...
Meanwhile bought icarsoft i905 which should be able to monitor AHC temp and pressures
Will check with Techstream too
Any other way to determine which component is out of order?
Thanks again...
Arnonmg
One point that need clarification -
I assume Globes=Actuators ?
Are they work as accumulator??
If they are kind of accumulators and their membrane wears off then the pump should show some warning like high temp
Since AHC link to VSC / TRC I assume there will be other warnings as well - do you know what will be the default warnings for imbalance between struts ?
Warning for pump?
Really Appreciate your comments,
Still looking for specialist in Israel ...
Meanwhile bought icarsoft i905 which should be able to monitor AHC temp and pressures
Will check with Techstream too
Any other way to determine which component is out of order?
Thanks again...
Arnonmg
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You will not find a specialist for the AHC in Israel - Based on that most dealers that have sold vehicles with AHC have no-one that even remotely understands the system - and I believe that the 100 has not been sold in Israel at all.
For code-readers - The HDJ100 does not have OBD2, only M-OBD.
Globes are screwed onto the actuator.
Globes are a type of accumulator, but t0yota calls only the main accumulator (cylindrical thingy) by that name.
There is no warning for busted globes, and no way that the system could detect it. You check globes by checking (counting level marks) the difference in fluid level in the reservoir between Lo and Hi. But only after checking ride heights and fluid pressure.
There is no warning for imbalance between left and right, only that everything stops working if the height reading between L & R is bigger than a certain limit.
Warning for pump is over-temp and over-pressure. And the pump can wear out as well - if you use it as a toy every day....
You really need to sit down with the manual for a couple of days - and forums for another 2. Most of this is already answered. The introductory part of the FSM has detailed info on most systems of the LC100.
For code-readers - The HDJ100 does not have OBD2, only M-OBD.
Globes are screwed onto the actuator.
Globes are a type of accumulator, but t0yota calls only the main accumulator (cylindrical thingy) by that name.
There is no warning for busted globes, and no way that the system could detect it. You check globes by checking (counting level marks) the difference in fluid level in the reservoir between Lo and Hi. But only after checking ride heights and fluid pressure.
There is no warning for imbalance between left and right, only that everything stops working if the height reading between L & R is bigger than a certain limit.
Warning for pump is over-temp and over-pressure. And the pump can wear out as well - if you use it as a toy every day....
You really need to sit down with the manual for a couple of days - and forums for another 2. Most of this is already answered. The introductory part of the FSM has detailed info on most systems of the LC100.
BobMurphy
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arnonmg
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Good News...
I got my icarsoft i905 today ...
Plug it into the DLC and it's working!!!
Can read pressures and height of AHC and totally 52 sensors
Here is what I getting:
N position - front 7.5 rear 7.5
Pump / accumulator 10.5
H position - front 9.9 rear 8.5
L position- front 3.8 rear 6.9
When I change positions again I got different results ...
N position stay at 3.8 front and 8.5 rear
When the engine turn off (switch on) the pressures show 0
In one case when engine turn off the car lower its height - the rear part went down instantly when the engine stopped (door was open and still...)
When I checked the mark test between low to high I got 3-4 marks !!!
Now I need some support here -
I assume that one more globes are busted
The AHC pump (electric) don't get hot and I don't see it working nonstop- it dose stop when height achieve
Height we measure look ok and equally (within 5 mm) height sensor show -2.4 mm front and rear
So - what do I do next?
How can I dictates which globe busted?
Is there a dumping test that I can do for each wheel ? Will it indicate on the globe quality?
So what next
Arnonmg
I got my icarsoft i905 today ...
Plug it into the DLC and it's working!!!
Can read pressures and height of AHC and totally 52 sensors
Here is what I getting:
N position - front 7.5 rear 7.5
Pump / accumulator 10.5
H position - front 9.9 rear 8.5
L position- front 3.8 rear 6.9
When I change positions again I got different results ...
N position stay at 3.8 front and 8.5 rear
When the engine turn off (switch on) the pressures show 0
In one case when engine turn off the car lower its height - the rear part went down instantly when the engine stopped (door was open and still...)
When I checked the mark test between low to high I got 3-4 marks !!!
Now I need some support here -
I assume that one more globes are busted
The AHC pump (electric) don't get hot and I don't see it working nonstop- it dose stop when height achieve
Height we measure look ok and equally (within 5 mm) height sensor show -2.4 mm front and rear
So - what do I do next?
How can I dictates which globe busted?
Is there a dumping test that I can do for each wheel ? Will it indicate on the globe quality?
So what next
Arnonmg
arnonmg
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Had a question I forgot to ask -
I noticed that when I start the car on the morning it is leveling and raise up the from slowly
It dose not happening every day but when it's happening it will be in the morning- first time I start the car.
Is it normal?
The height show N steady - no blinking
Another think I noticed is that sometimes when I turn off the engine the car lower the height relatively fast - kind of releasing pressure especially the rear part
Again - it's happening randomly
Any idea?
Arnon[
Arnonmg
I noticed that when I start the car on the morning it is leveling and raise up the from slowly
It dose not happening every day but when it's happening it will be in the morning- first time I start the car.
Is it normal?
The height show N steady - no blinking
Another think I noticed is that sometimes when I turn off the engine the car lower the height relatively fast - kind of releasing pressure especially the rear part
Again - it's happening randomly
Any idea?
Arnon[
Arnonmg
Ken Brenton
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Sounds like you are loosing pressure somewhere in the AHC system. That is not normal, my 100 sits at the same height all the time unless you select H or L.
Lars Bo Kjeldstrom
Member
If you come to a stop, and right away stop the engine -your AHC might not be levelled right, so when you turn it on the next time, it starts levelling. I always wait some 20 secs before turning the engine off after driving, also to allow the turbo to rev down before cut off!
Your issue with the lowering after engine cut off sounds strange! Cutting off engine should stop all AHC activity -as should an open door!
LB
Your issue with the lowering after engine cut off sounds strange! Cutting off engine should stop all AHC activity -as should an open door!
LB
arnonmg
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Usually I wait minute or two before engine off unless it was very short drive - like 5 min
This leveling process dose not happening every day - it is more like every couple of days
I am going to service the AHC with fresh oil and bleeding each and every vent possible... Hope to get better performance
Before I service the AHC I am going to take height reading with my scanner every morning for few days and look for some pattern
Maybe there's leakage somewhere in the system which result with loosing height after 12 hours sleeping...
I will try to figure out what happening after I get some data and then move to next step
I think it will be wise to monitor the the pressure and height before replacing oil etc - maybe there's something wrong with globe, pipe, pump etc..
Let me know if anyone had pressure loss in the AHC system ?
Where was the failure ?
How did you determine that you have pressure loss ?
Note that up to now I did not found any leakage, the AHC oil level is steady
Thanks
Arnonmg
This leveling process dose not happening every day - it is more like every couple of days
I am going to service the AHC with fresh oil and bleeding each and every vent possible... Hope to get better performance
Before I service the AHC I am going to take height reading with my scanner every morning for few days and look for some pattern
Maybe there's leakage somewhere in the system which result with loosing height after 12 hours sleeping...
I will try to figure out what happening after I get some data and then move to next step
I think it will be wise to monitor the the pressure and height before replacing oil etc - maybe there's something wrong with globe, pipe, pump etc..
Let me know if anyone had pressure loss in the AHC system ?
Where was the failure ?
How did you determine that you have pressure loss ?
Note that up to now I did not found any leakage, the AHC oil level is steady
Thanks
Arnonmg
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It is normal that the ahc will adjust the height after stopping, but before turning off the engine. It is an AUTOmatic Height Control system, adjusting the pressure in the suspension according to changing conditions. The conditions do change between driving and standing still; and between driving uphill and downhill, e.g. But, if the car lowers after stopping the engine, you might have a leaking leveling valve; e.g. debris in the fluid.
If you get the pressures and heights within spec, and have 7 or less graduations fluid level change, going from low to high; then all your globes are busted. That would be noticable while driving. How is it on corrugated roads? That's one of the strenghts of this suspension system: washboards are nearly comfortable
If you get the pressures and heights within spec, and have 7 or less graduations fluid level change, going from low to high; then all your globes are busted. That would be noticable while driving. How is it on corrugated roads? That's one of the strenghts of this suspension system: washboards are nearly comfortable
arnonmg
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I can't really tel the difference since I have the car only for two month now but I notice a difference after replacing FR shock absorber
I did some checking over the weekend reading heights and pressure in N height -
Jan 30 morning:
Height
FR 6 mm
FL 9.8 mm
RR -9.2 mm
Pressure:
FR 7.7
RR 7.4
Acu 10.8
After driving
Height:
FR -10.4
FL -5
RR -5.4
Pressure:
FR 8.4
RR 7.5
Acu 10.6
Evening
Height:
FR -10.4
FL -10.4
RR -15.2
Pressure:
FR 8.4
RR 7.6
Acu 10.7
Jan 31 morning:
Pressure:
FR 8.7
RR 7.6
Acu 10.8
At all times I noticed 7 marks of fluid between high and low- but not more then 7...
There is short screaming from the pump when the accumulator reach the 10 or just before its stops
Checked also dumping SW and they are working
The height differences look odd to me but maybe small adjustments require
The pressure issue when I go from high to normal - no change in pressure - is it normal?
Arnonmg
I did some checking over the weekend reading heights and pressure in N height -
Jan 30 morning:
Height
FR 6 mm
FL 9.8 mm
RR -9.2 mm
Pressure:
FR 7.7
RR 7.4
Acu 10.8
After driving
Height:
FR -10.4
FL -5
RR -5.4
Pressure:
FR 8.4
RR 7.5
Acu 10.6
Evening
Height:
FR -10.4
FL -10.4
RR -15.2
Pressure:
FR 8.4
RR 7.6
Acu 10.7
Jan 31 morning:
Pressure:
FR 8.7
RR 7.6
Acu 10.8
At all times I noticed 7 marks of fluid between high and low- but not more then 7...
There is short screaming from the pump when the accumulator reach the 10 or just before its stops
Checked also dumping SW and they are working
The height differences look odd to me but maybe small adjustments require
The pressure issue when I go from high to normal - no change in pressure - is it normal?
Arnonmg
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The pressure reading is not real-time. It just reads the value of the pressure sensor on the pump at the moment when the level-valve closes. Then the software will give you a figure which is close to the truth for the event of going from Lo to Normal height. If you want to know the shock/globe pressure at any other time or position, you have to connect a gauge to the bleeder.
The reading of graduations change in the fluid level has to be done after getting pressures and heights into spec, if you want to determine the health of the globes/spheres (gas springs).
Have you checked the heights?
The front pressure is easy to adjust by cranking the torsion bars (jack up car first) until the pressure is within specs.
The rear pressure is also a bit high, but could be fixed by lowering the rear, probably about 1 cm would do the trick. Then, if the height differences from Lo to N and Hi are correct, you could count graduations.
Re The difference in height readings: You need a level ground (garage floor?) and always move from Lo to N before reading values. AND, the steering has to be straight, steering wheel less than 35 degrees off center. That has to be checked with the tester as well, there is a reading for steering wheel position. (The steering wheel is not necessarily straight, it's the sensor that counts for the AHC ECU.)
The reason for this is that when you turn left or right, the gate valve between right and left is closed, giving a different pressure on each side, and possibility for different heights.
When you adjust the torsion bars, you have to measure (physically) the height on the left and right to get the balance right, and make sure the gate valve is open then.
The reading of graduations change in the fluid level has to be done after getting pressures and heights into spec, if you want to determine the health of the globes/spheres (gas springs).
Have you checked the heights?
The front pressure is easy to adjust by cranking the torsion bars (jack up car first) until the pressure is within specs.
The rear pressure is also a bit high, but could be fixed by lowering the rear, probably about 1 cm would do the trick. Then, if the height differences from Lo to N and Hi are correct, you could count graduations.
Re The difference in height readings: You need a level ground (garage floor?) and always move from Lo to N before reading values. AND, the steering has to be straight, steering wheel less than 35 degrees off center. That has to be checked with the tester as well, there is a reading for steering wheel position. (The steering wheel is not necessarily straight, it's the sensor that counts for the AHC ECU.)
The reason for this is that when you turn left or right, the gate valve between right and left is closed, giving a different pressure on each side, and possibility for different heights.
When you adjust the torsion bars, you have to measure (physically) the height on the left and right to get the balance right, and make sure the gate valve is open then.
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arnonmg
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Hi uHu
Finally had got the AHC oil and time to bleed the system...
Replace 4-5 litter - saw that had air in the system and one of the rear shocks had really muddy fluid
Next deal with the pressures and bring the front to spec
front height was fine within 5mm side to side (-1 / -5)
Rear was more difficult- pressure is high 7.7 and height sensor show -12
Changing the sensor height help me bring the car to 20.5 inches but reading of height sensor stay -12
Could not understand this issue ...
I will look for rear springs now to bring the rear pressure to spec
Another thing that I saw - steering angle is 270 ..??
When I turn fully left it show over 1000 and guilt right -400
Straight show 270
Any idea?
Almost forgot- ride quality improved dramatically!!!
Thank you for your support and guidance
Arnon
TLC 100 IL
Finally had got the AHC oil and time to bleed the system...
Replace 4-5 litter - saw that had air in the system and one of the rear shocks had really muddy fluid
Next deal with the pressures and bring the front to spec
front height was fine within 5mm side to side (-1 / -5)
Rear was more difficult- pressure is high 7.7 and height sensor show -12
Changing the sensor height help me bring the car to 20.5 inches but reading of height sensor stay -12
Could not understand this issue ...
I will look for rear springs now to bring the rear pressure to spec
Another thing that I saw - steering angle is 270 ..??
When I turn fully left it show over 1000 and guilt right -400
Straight show 270
Any idea?
Almost forgot- ride quality improved dramatically!!!
Thank you for your support and guidance
Arnon
TLC 100 IL
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The steering angle sensor is something I haven't looked at. I have studied the books, and forums, but found nothing about how to zero it. The only thing I find reference to everywhere, is to go into the VGRS settings and zero the steeing angle. But, I don't have vgrs, and I suppose the same goes for you.
Mine is just a few degrees off, so I can adjust that on the tie-rods, and then just turn the steering wheel slightly to put it straight. But 270 degrees? The only thing I found out about the sensor is that it is an opto-coupler, a disc with holes and a light that shines through, but there must be something to tell it when it's passing zero as well? Or not?
I have been thinking of taking off the pad (and maybe the steering wheel as well) just to find out how it is put together, but as long as it doesn't give me a big problem...
Haven't seen this iCarSoft before, but I suppose it can read the codes right? What I've seen used elsewhere is TechStream, or the Toyota Tester.
Mine is just a few degrees off, so I can adjust that on the tie-rods, and then just turn the steering wheel slightly to put it straight. But 270 degrees? The only thing I found out about the sensor is that it is an opto-coupler, a disc with holes and a light that shines through, but there must be something to tell it when it's passing zero as well? Or not?
I have been thinking of taking off the pad (and maybe the steering wheel as well) just to find out how it is put together, but as long as it doesn't give me a big problem...
Haven't seen this iCarSoft before, but I suppose it can read the codes right? What I've seen used elsewhere is TechStream, or the Toyota Tester.
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