TechStream in Seattle...need help

[CanuckS100]

I've been trying to install but I keep running unti issues. I am looking to level out my AHC (move 8 ticks from low to high) as one side is an inch lover that the other side.
I normally dont reach out like this but does ayone have this software that can help me out this week? I'm up in Greenwood. Thanks!! James

 

[97 AZ LC]

Give us a better picture. Which side is an inch lower? Front, rear or front and rear?

 

[CanuckS100]

Give us a better picture. Which side is an inch lower? Front, rear or front and rear?

Driver side. Had full flush. 8 ticks in fluids movement. No rust underneath. 99 LX-190k.
I have a cheat sheet walking through the measurements, computer readings and torsion bar adjustments...I just need TechStream for reading the computer.

 

[IndroCruise]

I've been trying to install but I keep running unti issues. I am looking to level out my AHC (move 8 ticks from low to high) as one side is an inch lover that the other side.
I normally dont reach out like this but does ayone have this software that can help me out this week? I'm up in Greenwood. Thanks!! James

Too far away to help with Techstream -- but suggest as follows ....

The first order of business is 'cross-levelling' the front of the vehicle. The AHC system cannot help with this -- hydraulically impossible because Front Left and Front Right are connected at the same AHC pressure unless cornering at speed -- ditto Rear Left and Rear Right. Neither Techstream nor the Height Control Sensor adjusters can help with 'cross-levelling'.

Instead use a tape-measure and a wrench at the torsion bar adjusters to 'cross-level' the front of the vehicle as described in the first attachment -- aiming to equalise the Front Left and Front Right hub-to-fender distances. When the Front is 'cross-level' then the Rear also will be as 'cross-level' as possible UNLESS there are issues or wear or distortions in the mechanical suspension (including axles, bearings balljoints), or chassis, or tyres.

Then Techstream (or other suitable scanner capable of reading the AHC Electronic Control Unit) is necessary to help in setting the 'ride height' used at "N" -- for which the Height Control Sensor adjusters are used (and not the torsion bar adjusters).

When 'cross level' is correct and 'ride heights' at "N" are where you want them (typically Front 19.75 inches, Rear 20.50 inches hub-to-fender on a stock vehicle), then and only then, it is time to use Techstream or similar to adjust Front AHC pressures using torsion bar adjusters and decide what to do about Rear AHC pressures -- usually spacers and/or upgraded coil springs.

Then when AHC pressures are within the FSM-specified ranges, the number of "ticks" or graduations measured at the AHC tank between "LO" and "HI" heights can be compared with the FSM (see extract attached) to give an indication of the overall condition of the four 'globes'.

This thread may help:

The ABCs of AHC - How to Measure, Flush, and Adjust all in one place

forum.ih8mud.com

 

[CanuckS100]

Too far away to help with Techstream -- but suggest as follows ....

The first order of business is 'cross-levelling' the front of the vehicle. The AHC system cannot help with this -- hydraulically impossible because Front Left and Front Right are connected at the same AHC pressure unless cornering at speed -- ditto Rear Left and Rear Right. Neither Techstream nor the Height Control Sensor adjusters can help with 'cross-levelling'.

Instead use a tape-measure and a wrench at the torsion bar adjusters to 'cross-level' the front of the vehicle as described in the first attachment -- aiming to equalise the Front Left and Front Right hub-to-fender distances. When the Front is 'cross-level' then the Rear also will be as 'cross-level' as possible UNLESS there are issues or wear or distortions in the mechanical suspension (including axles, bearings balljoints), or chassis, or tyres.

Then Techstream (or other suitable scanner capable of reading the AHC Electronic Control Unit) is necessary to help in setting the 'ride height' used at "N" -- for which the Height Control Sensor adjusters are used (and not the torsion bar adjusters).

When 'cross level' is correct and 'ride heights' at "N" are where you want them (typically Front 19.75 inches, Rear 20.50 inches hub-to-fender on a stock vehicle), then and only then, it is time to use Techstream or similar to adjust Front AHC pressures using torsion bar adjusters and decide what to do about Rear AHC pressures -- usually spacers and/or upgraded coil springs.

Then when AHC pressures are within the FSM-specified ranges, the number of "ticks" or graduations measured at the AHC tank between "LO" and "HI" heights can be compared with the FSM (see extract attached) to give an indication of the overall condition of the four 'globes'.

This thread may help:

The ABCs of AHC - How to Measure, Flush, and Adjust all in one place

forum.ih8mud.com

Thanks for the details here! I measured and found these:

	Left	Right
Front	18 7/8"	19 1/4"
Rear	20 1/4"	20 7/8"

By what I understand I just need to turn the front-left torsion bar clockwise till it and the front-right sides are even eh? PLUS getting them up to OE levels of 19.75", which might require clockwise turns on the front-right side as well.
Then, because of that adjustment, the AHC system will attempt to level the entire system and potentially lift the rear accordingly.

Am I tracking right?
Should I also loosen the lower control arms to avoid bushing binding before adjusting the torsion bar?

 

[IndroCruise]

Thanks for the details here! I measured and found these:

	Left	Right
Front	18 7/8"	19 1/4"
Rear	20 1/4"	20 7/8"

By what I understand I just need to turn the front-left torsion bar clockwise till it and the front-right sides are even eh? PLUS getting them up to OE levels of 19.75", which might require clockwise turns on the front-right side as well.
Then, because of that adjustment, the AHC system will attempt to level the entire system and potentially lift the rear accordingly.

Am I tracking right?
Should I also loosen the lower control arms to avoid bushing binding before adjusting the torsion bar?

Yes -- you are getting there!!

Imagine the chassis attachment points as corners of a perfect, stiff rectangle in one plane. (For the previously given reasons, things are never quite perfect on a vehicles of this age and there will be some manufacturing tolerances as well -- but set all that aside for the moment).

If all is factory-perfect, and provided the vehicle is on level ground and loads equally distributed, then when Front Left is low, expect Rear Right to be high -- which is exactly what you see in your numbers.

So when you adjust Front 'cross-level' as you describe, then that also will result in at least some of the needed correction at the Rear.

The 'cross-level' adjustment will not (and cannot) alter the 'ride height' at the Front nor the Rear. When the engine is turned on -- maybe with a trip around the block to allow things to settle after adjustment --the AHC system will cause both Front and Rear to return to exactly the same heights at "N" as set long ago by the Height Control Sensor adjusters -- which is exactly what the AHC system is designed to do within its load limits.

The system appears to 'average' the Front Sensor readings -- unless Height Control Sensor signals are widely different, in which case the AHC Electronic Control Unit (ECU) will be unable to resolve the signals and instead will place the vehicle in 'fail safe function'. Then none of the AHC and TEMS functions will work as expected.

To be clear, 'cross-levelling' can be used to correct a lean in the absence of other mechanical suspension and tyre defects (and correct unequal loading on Left and Right torsion bars which is the underlying cause of the lean).

Different to a conventional Land Cruiser IFS suspension, torsion bar adjustment on an AHC suspension cannot result in a 'ride height' change -- because that is determined by the AHC ECU and the Height Control Sensors -- and the ECU has no idea what the torsion bars are doing.

'Ride height' change requires moving the Height Control Sensor adjusters -- and that can be discussed when you get to that point.

So, when load is added to or removed from the torsion bars while height is kept constant by the AHC system, then the corresponding load is added to or removed from the AHC system -- and there is a commensurate change in AHC pressures.

Simply said, the total vehicle weight is shared between the mechanical suspension and the AHC suspension.

The torsion bar adjusters have only two purposes on a vehicle with AHC suspension:

• 'cross-levelling', and,
• Front AHC pressure adjustment by using the torsion bar adjusters to transfer weight shares between the mechanical suspension and the AHC suspension.

The sequence mentioned in my previous post #4 in this thread is important whenever tuning or adjusting suspension on an AHC-equipped vehicle.

Mastering Techstream or some other AHC-reading scanner also is important -- as well as diagnostic assistance and revealing Diagnostic Trouble Codes (DTC's), a scanner is essential to make necessary adjustments to keep AHC pressures within the FSM-specified ranges for good damping performance (meaning comfort), and, for long life of the system.

And no, loosening control arm bushes is not necessary when making adjustments.

Probably you will find after 'cross-levelling' that your 'ride heights' are "near enough good enough" and pursuit of perfection is not worthwhile.

Next step is getting a good understanding of your AHC pressures -- very important.

 

[CanuckS100]

Yes -- you are getting there!!

Imagine the chassis attachment points as corners of a perfect, stiff rectangle in one plane. (For the previously given reasons, things are never quite perfect on a vehicles of this age and there will be some manufacturing tolerances as well -- but set all that aside for the moment).

If all is factory-perfect, and provided the vehicle is on level ground and loads equally distributed, then when Front Left is low, expect Rear Right to be high -- which is exactly what you see in your numbers.

So when you adjust Front 'cross-level' as you describe, then that also will result in at least some of the needed correction at the Rear.

The 'cross-level' adjustment will not (and cannot) alter the 'ride height' at the Front nor the Rear. When the engine is turned on -- maybe with a trip around the block to allow things to settle after adjustment --the AHC system will cause both Front and Rear to return to exactly the same heights at "N" as set long ago by the Height Control Sensor adjusters -- which is exactly what the AHC system is designed to do within its load limits.

The system appears to 'average' the Front Sensor readings -- unless Height Control Sensor signals are widely different, in which case the AHC Electronic Control Unit (ECU) will be unable to resolve the signals and instead will place the vehicle in 'fail safe function'. Then none of the AHC and TEMS functions will work as expected.

To be clear, 'cross-levelling' can be used to correct a lean in the absence of other mechanical suspension and tyre defects (and correct unequal loading on Left and Right torsion bars which is the underlying cause of the lean).

Different to a conventional Land Cruiser IFS suspension, torsion bar adjustment on an AHC suspension cannot result in a 'ride height' change -- because that is determined by the AHC ECU and the Height Control Sensors -- and the ECU has no idea what the torsion bars are doing.

'Ride height' change requires moving the Height Control Sensor adjusters -- and that can be discussed when you get to that point.

So, when load is added to or removed from the torsion bars while height is kept constant by the AHC system, then the corresponding load is added to or removed from the AHC system -- and there is a commensurate change in AHC pressures.

Simply said, the total vehicle weight is shared between the mechanical suspension and the AHC suspension.

The torsion bar adjusters have only two purposes on a vehicle with AHC suspension:

• 'cross-levelling', and,
• Front AHC pressure adjustment by using the torsion bar adjusters to transfer weight shares between the mechanical suspension and the AHC suspension.

The sequence mentioned in my previous post #4 in this thread is important whenever tuning or adjusting suspension on an AHC-equipped vehicle.

Mastering Techstream or some other AHC-reading scanner also is important -- as well as diagnostic assistance and revealing Diagnostic Trouble Codes (DTC's), a scanner is essential to make necessary adjustments to keep AHC pressures within the FSM-specified ranges for good damping performance (meaning comfort), and, for long life of the system.

And no, loosening control arm bushes is not necessary when making adjustments.

Probably you will find after 'cross-levelling' that your 'ride heights' are "near enough good enough" and pursuit of perfection is not worthwhile.

Next step is getting a good understanding of your AHC pressures -- very important.

WOW! You're a bundle of amazing knowledge! Thanks so much...you deserve a hug and a beer! Note necessarily in that order.
With doing some adjusting, this is where I currently am and feel that I can adjust a little more, the left side has been turned quite a bit and doesn't seem to yield large results.

	Front to back location	Left (NA Driver's Side)	Right (NA Passenger Side)
Original Setting	Front Back	18 7/8" 20 1/4"	19 1/4" 20 7/8"
1) Left side adjust clockwise 5x's	Front Back	18 7/8 20	19 1/4 20 3/4
2) Started LX and went to Low then Normal	Front Back	19 1/4 20 1/4	19 5/8 20 5/8
3) Right side adjust counter-clockwise 2x's (Low then Normal)	Front Back	19 1/4 20 1/4	19 1/2 20 1/2
4) Left side adjust clockwise 2x's (Low then Normal)	Front Back	19 3/8 20 1/4	19 1/2 20 1/2

 

[IndroCruise]

WOW! You're a bundle of amazing knowledge! Thanks so much...you deserve a hug and a beer! Note necessarily in that order.
With doing some adjusting, this is where I currently am and feel that I can adjust a little more, the left side has been turned quite a bit and doesn't seem to yield large results.

	Front to back location	Left (NA Driver's Side)	Right (NA Passenger Side)
Original Setting	Front Back	18 7/8" 20 1/4"	19 1/4" 20 7/8"
1) Left side adjust clockwise 5x's	Front Back	18 7/8 20	19 1/4 20 3/4
2) Started LX and went to Low then Normal	Front Back	19 1/4 20 1/4	19 5/8 20 5/8
3) Right side adjust counter-clockwise 2x's	Front Back	19 1/4 20 1/4	19 1/2 20 1/2
4) Left side adjust clockwise 2x's	Front Back	19 3/8 20 1/4	19 1/2 20 1/2

Great progress!! The Good Book a.k.a. FSM (see extract attached to previous Post #4) mentions a tolerance of 10 millimetres (translates to 0.39 inches) difference between Left and Right levels in the 'cross-levelling' process, so your vehicle is in good shape already.

Yes -- even though I have warned against 'pursuit of perfection' I am inclined to suggest giving things another little tweak to see if they can be made to match without trying too hard. Suggest drive around the block first to make sure that the suspension has settled, then return to same level place and re-measure. Very roughly, one (1) full turn of a torsion bar adjuster should result in about one-eighth inch (say 3 millimetres) of movement -- but as you probably have discovered already, movement may not always be consistent with that guideline! Expect some variation and take multiple measurements -- stiffness in bushes, wear and tear etc in the suspension can be the cause of slightly different numbers from time to time.

If you then wish to tweak the actual 'ride heights' -- this is quite different to 'cross-levelling' -- then peruse the "The ABCs of AHC" thread prepared by @LndXrsr via the link at Post #4 in this thread. This explains how to utilise the Height Control Sensor adjusters for this purpose. Frankly, it is matter of preference -- personally I would not bother to pursue the last quarter-inch (6 millimetres) of 'ride height' showing on your vehicle.

The height settings of the vehicle affect the AHC pressures. When the vehicle is higher, then the torsion bars and springs are more relaxed and carry less load, because the vehicle has been 'jacked up' by the AHC part of the suspension and which is then carrying more load. This means higher AHC pressures.

So 'ride height' and 'AHC pressures' are interdependent -- like two sides of the one coin.

When 'ride heights' are where you want them at "N" height setting, then, and not before then, it is time to check and adjust AHC pressures consistent with the FSM-specified ranges.

The FSM specifies these ranges with a stock vehicle (no accessories or additions), on level ground, empty of all loads, no driver and no passengers, full fuel, front wheels straight ahead.

In practice, this is best done when the vehicle is carrying its permanent accessories and fittings and its usual load. This is because the AHC pressures have an optimal effect on damping performance when the AHC pressures are in the FSM-specified ranges -- neither too high nor too low -- PROVIDED THAT the 'globes' are in good condition (more about that later).

So it seems best to set AHC pressures when the vehicle is in its most likely travelling condition. Too low AHC pressures or too high AHC pressures mean reduced damping and an uncomfortable, 'springy' ride. In addition, high AHC pressures challenge the internal seals and result in leaks and eventually shorter component life.

At this point, suggest don't miss the excellent video prepared by @suprarx7nut :


So finally an answer to your original question at your Post #1 ....

Techstream or some other scanner is essential when setting AHC pressures -- and for assistance in range of diagnostic purposes. Techstream is the 'tool of choice' because of its wide functionality and because there is so much information on IH8MUD, especially at
How-To: TechStream In 5 Minutes - https://forum.ih8mud.com/threads/how-to-techstream-in-5-minutes.1034923/#post-11416736
but also elsewhere.

If Techstream proves difficult, then suggest explore alternatives. For example:
Post #34 at this link:

AHC rough ride, with readouts from ecu

How have people found this device for pressures is it easy to use and how is it set up with your phone ?.Thanks. Bluetooth, there's an app for your phone and instructions come with the device

forum.ih8mud.com

When correct AHC pressures are set at "N" within FSM-specified ranges, then it is time to compare the results of the "HI/LO Test" with FSM specification (also attached to Post #4 in this thread).

A difference of 14 graduations at the AHC Tank between "LO" height setting and "HI" height setting indicates near-new 'globes'. When results of this test have deteriorated to a difference of 7 graduations (usually after 10 or more years), then it is time to consider new ' globes' -- best price for four (4) 'globes' landed in USA or Canada and many other places is around USD500 to USD600 from IMPEX JAPAN — online new genuine spare parts shop - https://en.impex-jp.com/ -- Part numbers Front 49141-60010 (two required); Rear 49151-60010 (two required).

Just to be clear about a common misunderstanding: correct AHC pressures by themselves tell nothing about the overall condition of the AHC 'globes'.

When the "HI/LO Test" is done at correct FSM-specified AHC pressures and repeated over time (years), it gives a comparison of the steadily decreasing volume of fluid displaced by the 'globes' under the effect of the remaining but slowly dissipating nitrogen pressure behind the membranes in the 'globes', while the volume displacements in the "HI" <> "LO" movements of the 'shock absorbers' remain the same. The loss of 'globe' nitrogen pressure corresponds to a decrease in damping performance. Declining 'comfort' usually is noticed as this test gets closer to 7 graduations. When this test is done at non-FSM AHC pressures, then the reading is not comparable with anything and the results are not informative.

So to summarise, the sequence for tuning a "100 series" AHC suspension is as follows:

1. persist with Techstream or some other scanner which is able to read the AHC ECU,
2. adjust for cross-level,
3. adjust or confirm 'ride heights',
4. adjust AHC pressures -- torsion bar adjustment at Front, spacers and/or spring replacements at Rear,
5. check 'globe condition' using "HI/LO Test" measuring fluid level differences at AHC Tank, consider replacement 'globes' if necessary,
6. Repeat steps 2 to 5 to check for consistency of results.

Meanwhile, the attachment is recommended reading for all owners of "100 series" AHC suspensions -- it provides a General Description with diagrams of how all the parts of the AHC and TEMS systems are meant to work together.

And by the way, thank you for the acknowledgements. I am just one of the ancient story-tellers -- the "bundle of knowledge" actually comes from the wide IH8MUD community accumulated over many years -- but I never object to a few more "likes" to add to my collection!!

 

[CanuckS100]

Thanks for all of the time and guidance. I am about an 1/8 from side-to-side now so thank you VERY much! I think my main takeaway will adjusting the torsion bars is to: make the nut locations before turning them, take details notes about about which side I turned & the measurements AFTER taking it for a spin around the block, and feel free to take shorter turns (doesn't have to be a full revolution). That was the winner for me in the end.
Again, thanks for ALL of the help! You're an invaluable resource to this community!!!

 

[IndroCruise]

Thanks for all of the time and guidance. I am about an 1/8 from side-to-side now so thank you VERY much! I think my main takeaway will adjusting the torsion bars is to: make the nut locations before turning them, take details notes about about which side I turned & the measurements AFTER taking it for a spin around the block, and feel free to take shorter turns (doesn't have to be a full revolution). That was the winner for me in the end.
Again, thanks for ALL of the help! You're an invaluable resource to this community!!!

No problem. You already have it worked out. Attached is a previous but forgotten note written long ago in response to a different IH8MUD inquiry -- probably not necessary for you now but offered for completeness.

 

[CanuckS100]

No problem. You already have it worked out. Attached is a previous but forgotten note written long ago in response to a different IH8MUD inquiry -- probably not necessary for you now but offered for completeness.

I am WAY delayed in saying this, but thank you for sending that attachment!

I am back at it and replaced my globes. I've bled the system twice, but the drive is unbearable...like the truck is going to break on me. I figure I need to adjust the torsion bars, but need to read the pressures to know how to adjust. I can't get Techstream to work me...I don't think there's anyone around Seattle with Techstream, so is there another tool that I buy off of Amazon or something?