P38A EAS woes. I'm at the end of my tether

dubbleRR · Jan 4, 2021

2 pence worth ...Is the compressor making good air pressure /if its been feeding a leak for some time ,its probably tired and will run near constant to make pressure

..

Henry_b · Jan 4, 2021

kermit_rr said:
If it was a single sensor that was out, how would it level while the engine was running? My limited knowledge says the car should level down in that case?

The car levels when at a standstill if she's on the píss, however it shouldn't dance around..

If the sensor is not calibrated or it is faulting it will "level" to what it thinks is correct however it will have the lean.

When the car is turned off the EAS will level down to the lowest corner, but if it it is staying up on all 3 corners bar one that to me shows a sensor issue.

If there are no leaks at the bag or the lines to the bag then the next port of call is the valveblock if the valveblock is fine the sensor is the next probable cause.

Mine used to level down on the NSR a good 6cm and it was a dicky sensor

Henry_b · Jan 4, 2021

To eliminate the sensor as a cause replace the Delay relay with a 4-pin relay.

Once the key is turned off with a 4pin relay in place the EAS is "turned off or disabled" if she still drops with a 4 pin then you have an air leak and not a sensor fault.

EAS will work fine with the 4 pin when the car is running BTW.

kermit_rr · Jan 4, 2021

Henry_b said:
To eliminate the sensor as a cause replace the Delay relay with a 4-pin relay.

Once the key is turned off with a 4pin relay in place the EAS is "turned off or disabled" if she still drops with a 4 pin then you have an air leak and not a sensor fault.

EAS will work fine with the 4 pin when the car is running BTW.

I started mine up with no relay plugged in, it complained bitterly but thats all

Gvmclean · Jan 5, 2021

Right. A day of investigations has led me to a faulty sensor. Again, I'll never trust brand new parts in future. Chain of events;

-turn off car
-immediate drop from rear nearside corner
-live read of sensor values show all at the nominal value of 95-97
-visually the corner is dropped a long way
-install shraeders and inflate all to 45cm from centre of hub to wheel arch
-check at end of day and one side has dropped slightly due to schraeders having tiny, almost imperceptible leak
-new sensor ordered

DarthDude · Jan 5, 2021

Hang on- are you saying the height sensor reading for the nearside rear remained at 95-97 even after the corner dropped? How can you tell if you've switched off the engine?

Gvmclean · Jan 5, 2021

I am saying that, yes. The RSW version 2 tells you live sensor heights with the engine off but the key at position 2.

DarthDude · Jan 5, 2021

Erm.... how long from engine off to the drop to you reading off the value? I mean- how long did you wait from the time you turned off the engine to the time you read the height sensor value?

Gvmclean · Jan 5, 2021

Almost immediately. I think I've pretty much diagnosed it as a faulty sensor now. It's all very reminiscent of the issue Henry b described.

DarthDude · Jan 5, 2021

Erm....... does anybody know how long the EAS "relay" delays the height sensor readings for? I don't and I'm trying to google it.

Gvmclean · Jan 5, 2021

I'll tell you right now, unless mine is goosed of course, it is about 3 millionths of a millisecond..... Now, mine might not be fully functioning but that's the time I get on my stopwatch count

DarthDude · Jan 5, 2021

Ok man... thanks for that and I hope it works out for you. Let us know how it went!

Gvmclean · Jan 5, 2021

Honestly, thank you everyone for your advice and musings. It was more of a vent/rant about how my dear old girl is pushing my purist boundaries but has helped me gather my thoughts to find the real issue (hopefully)

Mark Piercy · Jan 5, 2021

Gvmclean said:
Honestly, thank you everyone for your advice and musings. It was more of a vent/rant about how my dear old girl is pushing my purist boundaries but has helped me gather my thoughts to find the real issue (hopefully)

Also, check behind the kick panel in the passenger foot well. There are two white blocks that corrode they'll need to be cut out, soldered and heat shrink. They can cause alkinds of mayhem with speakers and suspension.
Did you check the height sensor on the bench and did you watch the height sensor on the live Data for twitching while the system was operating?

RangeRoller dt · Jan 5, 2021

You had a good day 16

.

Gvmclean · Jan 5, 2021

Without being condensed, I'm at around day 418 with constant 'niggles'. This current niggle happened mid blend motor change.....only passenger side to do still.

pwood999 · Jan 5, 2021

According to the EAS Sys Info Doc, the delay should be 100 seconds after Ignition off, or 30 seconds after last door closes. I suspect the time delay varies as the relay ages, but never measured it.

With EAS Unlock, you might be able to tell by checking the idle data flow to see how long before it stops ?

DarthDude · Jan 5, 2021

pwood999 said:
According to the EAS Sys Info Doc, the delay should be 100 seconds after Ignition off, or 30 seconds after last door closes. I suspect the time delay varies as the relay ages, but never measured it.

With EAS Unlock, you might be able to tell by checking the idle data flow to see how long before it stops ?

View attachment 226964

OOoooo!! Thanks for that!

Well, as a new height sensor is already en route, I sure hope it works out for @Gvmclean but I'm wondering why the ECU would command the nearside rear to drop if the height sensor was constantly reading 95-97, faulty or not.

In order to drop, the exhaust valve (port 6) and nearside rear valve (port 1), would have to be open.... or leaking, and IF it's a leak then the speed of the drop implies a BIG leak. The good news is that both those are on the top of the valve block and easy to audit without having to remove it. I'd have been tempted to audit those valves before I bought the height sensor, but never mind all that for now, let's just hope it's the height sensor after all.

pwood999 · Jan 5, 2021

It would still be useful to see live data from a Nanocom recording. Maybe the FR is also rising and impacting rear left drop ?

DarthDude · Jan 6, 2021

Yes I agree. It's very important to be methodical and patient when dealing with the EAS and I've learnt those virtues- which don't come naturally to me- expensively and accompanied by exquisite pain over the years and a live reading of the height sensor data from power up to shut down (compared with the observed actual height of the car during that time) would have been very helpful.

The Schrader valves were a first step to eliminate leaks at the airline and airpsrings. Once those were known-good, I'd have moved him to do the same with the dryer and reservoir (8mm Schrader valve on port 7) and once that was known-good, onto auditing the aforesaid nearside rear and exhaust valves with the valve block in situ, and then to removing and auditing the rest of the valve block itself, and.... well you get the idea. You really need to go component by component, fixing any issues you might find as you go in order to be sure you don't overlook anything as there could be multiple issues at play and to ensure you don't buy unnecessary stuff, all of which are expensive given Land Rover's pricetags.

Well that's what I've learnt anyways. For what it's worth, I'd have made darned sure the mechanical components- especially the valve block with its many potential points of failure- were sound before moving on to the electronics, of which the driver board and height sensors are the usual suspects. My guess would be an issue with valve 1 and maybe valve 6 given that the airlines and nearside rear airspring are now known-good.

But that's just me, let's just hope the new height sensor solves the issue.

P38A EAS woes. I'm at the end of my tether

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