The Toyota Landcruiser Owners Club

[wildsmith]

I think Willy's suggestion of checking it's not the tyre type or pressure seems a good candidate. I think on rough tarmac the tyres do most of the work smoothing out the bumps.
_________________
Jon m0zxj

01 UZJ100 lifted (AHC & 40mm BL), ARB locked f&r, cryo'd 4.88's, TJM front bumper, 12k goldfish, sliders, rack, snorkel, 35's, storage, aux power etc.
93 HDJ80 sold
94 HDJ80 RIP

[london mc]

I know tyre pressure makes a difference, especially on larger tyres, but the ptoblem Tom was referring to is more like a complete lack of suspension...not sure this could be attributed to pressure...??

However, perhaps tom HAS fixed the issue but the pressures are so off that he is getting rough feedback from the road..

tom..when you have had a chance to check the pressures etc. perhaps re0try the car and let us know how you get on...on my own vehicle it is so bouncy on the road that going over speed bumps now requires to utmost care! lift off is imminent I am sure..

would be good to get this bottomed out on the forum if possible, I really need some suspension back in the car

Tom mc

[jpmay]

Hi,

My 2005 model V8 amazon had the sensors replaced a year ago; it worked OK since then.

A week ago my wife happened to drive through some extreme mud.

Since that day ............................ the suspenion has not worked properly:

Sometimes it is stuck on high; no matter what it will not move up and down when you are stationary; possibly the four wheels are uneven at times.

So, it's bad news.  (Naturally we need the car for a long trip in a couple days.)

I actually DO NOT KNOW WHERE THE SENSORS ARE ... how to locate them ??

Could anyone help me with that?  perhaps a pic?  thanks a million.

(I know Nor has a pic of the insides of a sensor!)

Thanks again, J.P.

[wildsmith]

Here's the suspension and axle chapter from RM616E. There have been a few suppliments issued that may have changes but I don't have those merged yet.

http://www.mudtoys.com/manuals/100bits/sanda.pdf

Towards the bottom of the book marks you'll see the active suspension section.

EDIT: The suppliments cover some updates for the AHC pump for 2000 onwards but the rest is the same.
_________________
Jon m0zxj

01 UZJ100 lifted (AHC & 40mm BL), ARB locked f&r, cryo'd 4.88's, TJM front bumper, 12k goldfish, sliders, rack, snorkel, 35's, storage, aux power etc.
93 HDJ80 sold
94 HDJ80 RIP

[tom.]

jpmay cleaning and sealing sensors should help. Do not forget to mark position of sensor's link (or you can meassure gaps with caliper gauge in adjustment slot) before you unscrew it.


Thanks wildsmith. Have you got  pdf file  regarding Automatic Transmission (4 speed model)?

[tom.]

[wildsmith]

[wildsmith]

[jpmay]

Wildsmith, thanks for the link.  And Tom thanks for the tip!

It occurs to me -- the car generally WON'T move up and down ...

ie, it's generally just stuck there in the supposed middle position.

[Whether or not it is ACTUALLY in the middle position, the dash indicators show middle..]

So perhaps I am living in a fool's paradise thinking the only problem is the sensors.

Thanks ..

[wildsmith]

If you press the button to raise or lower it, does the light flash to indicate it's even thinking about it? You are trying it with the doors closed   ? Sensors does seem the most likely candidate. AFAIK the sensors are just a variable resistor (and if I ever get my hands on a spare one I'll take it apart to confirm that) so it wouldn't be hard to replace them with pots for in car manual control if they're really that flakey. In fact I think I'll put that on my mod list, just have to borrow a sensor from somewhere to experiment with and find out its values!
_________________
Jon m0zxj

01 UZJ100 lifted (AHC & 40mm BL), ARB locked f&r, cryo'd 4.88's, TJM front bumper, 12k goldfish, sliders, rack, snorkel, 35's, storage, aux power etc.
93 HDJ80 sold
94 HDJ80 RIP

[jpmay]

>If you press the button to raise or lower it, does the light flash to indicate it's even thinking about it?

Exactly correct.  (If you drive over 5mph, it more or less gives up and believes it is on Middle.)


>You are trying it with the doors closed?

Correct.  (Took days to figure that out when I first owned it!)


> Sensors does seem the most likely candidate.

Right.  I hope that is the case ....



>AFAIK the sensors are just a variable resistor (and if I ever get my hands on a spare one I'll take it apart to confirm that) so it wouldn't be hard to replace them with pots for in car manual control if they're really that flakey. In fact I think I'll put that on my mod list, just have to borrow a sensor from somewhere to experiment with and find out its values!

That is an outstanding idea!

there's a post on this ih8mud  forum... look up 100-series-cruisers slash 68491-ahc-problem.html.

which gives the relevant voltage values.

Cheers ...

[wildsmith]

Sounds like one or more position sensors have muck in them then. I'd expect the ECU to be able to detect that one or more sensors are out of range and give up, which it sounds like it's doing. I'd take the sensors off one at a time and take them apart to clean and re-seal. From everything I've read once cleaned and sealed they shouldn't be a problem again ... Mine are currently ok but when I have a little more time I'll be looking into having a manual overide. I like the flexibility of the AHC and would rather invest some time in improving it than just replacing it with standard springs.
_________________
Jon m0zxj

01 UZJ100 lifted (AHC & 40mm BL), ARB locked f&r, cryo'd 4.88's, TJM front bumper, 12k goldfish, sliders, rack, snorkel, 35's, storage, aux power etc.
93 HDJ80 sold
94 HDJ80 RIP

[tom.]

How to adjust the AHC sensors w/o tester: start engine, put AHC switch to "L", then to "N", inspect height.

(1) disconnect the connector of the front & rear height control sensors
(2) connect 3 dry cell batteries of 1.5v to SHB terminal and its negative to SHG terminal and apply approx 4.5v between the two terminals.
(3) Measure the voltage between terminals SHB and SHG. The target voltage (voltage between SHFL, SHFR, SHRR, and SHB) is the value divided by 2.

HINT: (example) Terminal voltage between SHB and SHG: 4.5v, target voltage: 2.25v.

(4) Measure the voltage between SHFL (SHFR, SHRR) and SHG terminals when voltage is applied.

Standard values:
front: target voltage +/- 0.08v
rear: target voltage +/- 0.07v

front connector :
SHFL
(SHFR)
X -----------X SHB

-------X SHG (dashes are just blanks. Should be two terminals on top, one on the bottom, like an upside-down triangle)

rear connector: (three terminals side-by-side)
SHG SHRR SHB
X ------X ------X

(5) Loosen nut and adjust the positions of the height control sensor link and front upper suspension arm or rear lower control arm by moving them up and down to install them.
(6) Tighten nut (torque 49 in-lbs)
(7) front sensor: When adjustment cannot be done by performing step (5), loosen the two nuts of height control sensor link and turn the link.
HINT: To raise the vehicle, turn link clockwise.
To lower vehicle, turn CCW.

(8) Tighten the two nuts (torque 48 in-lbs)
(9) Coat the threads of the link with sealer (P/N 08833-00070, three bond 1324)

--------------------------------------------------------------
How to test the AHC sensors:
Connect 4.5v (3 dry cells) at two terminals and test the voltage reading across the range. It will be 0.45 volts on one extreme of the range and 4.05V on the other.  
Target voltage: 2.25v in normal height position.


Ps. wildsmith it was very helpful, thank you. Could you send me this file regarding AT?

[jpmay]

Sadly I have not yet been able to affect a quick fix.

You know ........ now that I realize how incredibly simple these sensors are, it is absolutely ridiculous they cost £300.

I mean you could absolutely literally MAKE one (other than it being somewhat sealed against the elements) with two blocks of balsa wood, two strips of copper, and three pieces of wire.

It's plain ridiculous.  It's nothing other than the simplest possible potentiometer... in other words "a dial" !!

I'm sure you could actually glue in SIMPLY A 10 pence DIAL - like a volume knob - and it would work, if you were able to calibrate the resistance!

Ah well !

[wildsmith]