P38A Air suspension sucks

Datatek · May 7, 2023

Fingers13 said:
Hi all back on line, interesting reading re setting the heights. I cannot get that far unfortunately, if I press the EAS unlock and clear the faults it goes straight back into fault mode when I unplug and reset the comms code as per the instructions so it’s still sitting on the bump stops.

I might try re installing the software but I do get the good idle tab go green.

2 shocks were the wrong way round by the way Mark

Have you read the fauts?

Fingers13 · May 7, 2023

Yes FL sensor RL sensor & RR sensor faults which is all since they were replaced.

Datatek · May 7, 2023

Fingers13 said:
Yes FL sensor RL sensor & RR sensor faults which is all since they were replaced.

So, as I'm sure you are aware, you are not going to make any progress until you get to the bottom of those faults. The replacements were not cheap Chinese sensors by any chance? I'd be inclined to plug in one of your old sensors and see if that changes anything.

Fingers13 · May 7, 2023

Yep £25 each from Ebay, that will teach me. I’ll try to do some tests with the multimeter to see what, if any resistance I’m getting but I’m not very good at electrics. Annoying if both have failed though.

Datatek · May 7, 2023

Fingers13 said:
Yep £25 each from Ebay, that will teach me. I’ll try to do some tests with the multimeter to see what, if any resistance I’m getting but I’m not very good at electrics. Annoying if both have failed though.

I have had 2 cheapo's fail PDQ.

Fingers13 · May 7, 2023

Mine haven’t turned a wheel yet

am I safe to assume the Britpart ones are OK ?

Gord Wedman · May 7, 2023

Datatek said:
Which probably does not put the car at the designed level for normal height.

Is there a problem with "standard" being a little higher than factory? I don't think so. Lots of people have installed Johnson rods on LR3, LR4 and L322 without issue. This sets "standard" 2 inches higher than factory. You may say suspension parts will wear out sooner than they should but since we are always replacing parts on these old cars it hardly matters.

Datatek · May 8, 2023

Gord Wedman said:
Is there a problem with "standard" being a little higher than factory? I don't think so. Lots of people have installed Johnson rods on LR3, LR4 and L322 without issue. This sets "standard" 2 inches higher than factory. You may say suspension parts will wear out sooner than they should but since we are always replacing parts on these old cars it hardly matters.

No problem being higher other than for road use it will roll more and handle worse. That was not my point, I have never seen an EAS setup within spec where the bit counts of all sensors are identical. The sensors are not precision devices, setting all four corners to the same bit count is unlikely to result in 4 corners at the same height in particular front to rear.

Mark Piercy · May 8, 2023

On mine, the rears are always set 5 bits higher than the front settings. I run my standard height a touch higher than normal and the motorway setting a touch lower. With the terrafirma shocks the roll has been reduced along with help from the poly anti roll bar bushes.

In all honesty, Elliotts bus is much more pleasant with the standard shocks but each to their own.

Gord Wedman · May 9, 2023

Datatek said:
No problem being higher other than for road use it will roll more and handle worse. That was not my point, I have never seen an EAS setup within spec where the bit counts of all sensors are identical. The sensors are not precision devices, setting all four corners to the same bit count is unlikely to result in 4 corners at the same height in particular front to rear.

Well if one corner is a little higher or lower than it's other side I am not going to fart around with it. I don't actually think they are different but have not measured recently.

marjon · May 9, 2023

Gord Wedman said:
Is there a problem with "standard" being a little higher than factory? I don't think so. Lots of people have installed Johnson rods on LR3, LR4 and L322 without issue. This sets "standard" 2 inches higher than factory. You may say suspension parts will wear out sooner than they should but since we are always replacing parts on these old cars it hardly matters.

Have you looked at the changes in suspension geometry with 2 inches (on an L322) it’s huge for tyre wear issues.
I wonder if it was the reason they changed the motorway speed drop to 100mph.

Going down makes similar changes to going up.

On a P38 not, but on diff/prop angles long term?

keep it as close to standard is best.

J

Gord Wedman · May 9, 2023

marjon said:
Have you looked at the changes in suspension geometry with 2 inches (on an L322) it’s huge for tyre wear issues.
I wonder if it was the reason they changed the motorway speed drop to 100mph.

Going down makes similar changes to going up.

On a P38 not, but on diff/prop angles long term?

keep it as close to standard is best.

J

Well I don't offroad my L322 so it stays at normal height but there are lots of people that do jack them up and offroad them. There is a fellow on YouTube, Jay Tee, who does that.

Fingers13 · May 9, 2023

Hi all, quick update whilst awaiting new height sensors I check the connectors in the foot well for corrosion as previous posts and found the attached, a couple of pins were so corroded one fell out of the connector! List goes on.

brianp38dse · May 9, 2023

Well at least you can sort that out which should make things work better.
Time to get the solder and heat shrink out.

Grrrrrr · May 11, 2023

Fingers13 said:
Hi Mark, that's what i assumed but they crease up like an empty crisp packet. I did replace all the shocks, that's the nearest i got to the compressor & valves housing. I did use a 2 post car lift to do some work under the car so wonder if that would have done any damage?

If the wheels hung down the height sensors can drop out of the normal range and pick up some dirt so when the wheels are back up the height sensors give odd readings. If you check the resistance across the sensor arm as you move it through it range you shouldn't see any jumps. There's a lost somewhere on checking the height sensors. From memory there are 2 tracks. Datatek or pwood999 would know.

Datatek · May 11, 2023

Grrrrrr said:
If the wheels hung down the height sensors can drop out of the normal range and pick up some dirt so when the wheels are back up the height sensors give odd readings. If you check the resistance across the sensor arm as you move it through it range you shouldn't see any jumps. There's a lost somewhere on checking the height sensors. From memory there are 2 tracks. Datatek or pwood999 would know.

There are 2 concentric tracks in the height sensor but from a measurement point of view they appear as one.
Unhook the sensor arms and move the sensor back and forth through it's full travel a few times and then check with a meter that the change of resistance is smooth with no jumps or breaks as you move the arm.

Fingers13 · May 23, 2023

Hi all,
Thought id give a follow up on the conclusion. Having resolved my shock absorber discrepancy and replacing the height sensors with Dunlop OEM ones, I then re solder all the wires behind the front footwell panel and this has cured it

. My opinion for what its worth is the corroded connectors was the issue giving fault readings not the cheap sensors i fitted originally. I will take some height measurements in a couple of weeks after a few runs out just to check all is still level.

P38A Air suspension sucks

Datatek

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