EAS analysis from Nanocom - comparisons

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Grrrrrr

Grrrrrr

Technician, Bodgit & Scarper Ltd
Full Member
Posts
18,995
Location
Buckinghamshire, UK. ('95 DT)
One of the members on here (PWood, maybe?) inspired me to take a live trace of my EAS using my Nanocom. That was great but having it in front of me I suddenly realised I had no idea if what I was looking at was "normal" or not. So, I've taken a few of varying times and they all seem pretty consistent. I've also managed to get a trace off another member but it'd be nice to have others to compare if anyone has time and the interest? Preferably from a working EAS system but guess knackered is good too for comparison! The CSV files can be uploaded here if put in a zip archive. If you do decide to join in then please include year and model and if you're happy to be identified or not.

Not tried sharing like this before but think the files done so far can be found here:

https://drive.google.com/file/d/0By7n3F7TXDU8TnN0ZFVyUVZUc2M/edit?usp=sharing

https://drive.google.com/file/d/0By7n3F7TXDU8YjAzZDZmVklNcHc/edit?usp=sharing

Be aware that I've put several traces in the same files here with gaps where the stops were so you may need to fiddle a bit if you reuse the files.
 
One of the things that came out of the trace was that it fills the front bags when coming to a stop but also when starting from a standstill, regardless of whether the front bags are already at height or even above target. Stopping I guess I could see why but accelerating? To push front tyres harder onto the tarmac?
 
Grrrrrr said:
One of the things that came out of the trace was that it fills the front bags when coming to a stop but also when starting from a standstill, regardless of whether the front bags are already at height or even above target. Stopping I guess I could see why but accelerating? To push front tyres harder onto the tarmac?
Click to expand...

Every time the vehicle speed drops below 1 MPH the front valves open to equalise pressure across the axle. If one side has more pressure than the other (fat driver for instance) the front will drop when the brake is released the pressure will be put back into the bags to level car.
 
wammers said:
Every time the vehicle speed drops below 1 MPH the front valves open to equalise pressure across the axle. If one side has more pressure than the other (fat driver for instance) the front will drop when the brake is released the pressure will be put back into the bags to level car.
Click to expand...


A good job my missus isn't reading this ...
 
One thing that's starting to jump out at me is we are not seeing data from Nanocom that can be actually used for proper real-time analysis.

In the first 500 lines, just after you release the handbrake, there's a few entries that show the Corner valves opening without Inlet or Exhaust, but there is a height change. EDIT: I guess this is the L-R levelling Wammers mentions.

This leads me to believe the very slow rate or the EAS diagnostic data, is too slow to get a full line of concurrent readings . . . hence Nanocom gets a "last known state" for all values, but we cannot correlate, because the EAS ECU is reacting & controlling valves faster than the diagnostic data rate. For example :-
  • Line 465, the Exhaust valve opens and closes, followed by FL & FR on lines 457-461, but height went UP ?? This must be wrong ?
  • Lines 542-542 the Exhaust opens but no corner valves . . and height drops !!
There's more occurrences later on, but not analysed most of it. My Excel files show similar weirdness, but all it did was steer me to investigate the valve connectors (plenty in other posts about this)

FYI, I started down this road to better understand the ECU behaviour, and hopefully be able to link the data directly to the exact fault. While I was in total agreement with others experiences such as "random height changes are usually driver pack", the engineer in me wanted to prove it !! Bottom line is most faults are either exactly as per the HowTo, i.e. either Leaks, Leaks or the usual LR connector faults !!

Given the slow data rates, it would be more useful if Nanocom could be set to only log the values we actually need ! I will raise this as feature request on their forums when I get a minute. Maybe also a feature request for EAS Unlock ?

Pete
 
Last edited:
pwood999 said:
One thing that's starting to jump out at me is we are not seeing data from Nanocom that can be actually used for proper real-time analysis.

In the first 500 lines, just after you release the handbrake, there's a few entries that show the Corner valves opening without Inlet or Exhaust, but there is a height change.

This leads me to believe the very slow rate or the EAS diagnostic data, is too slow to get a full line of concurrent readings . . . hence Nanocom gets a "last known state" for all values, but we cannot correlate, because the EAS ECU is reacting & controlling valves faster than the diagnostic data rate. For example :-
  • Line 465, the Exhaust valve opens and closes, followed by FL & FR on lines 457-461, but height went UP ?? This must be wrong ?
  • Lines 542-542 the Exhaust opens but no corner valves . . and height drops !!
There's more occurrences later on, but not analysed most of it. My Excel files show similar weirdness, but all it did was steer me to investigate the valve connectors (plenty in other posts about this)

FYI, I started down this road to better understand the ECU behaviour, and hopefully be able to link the data directly to the exact fault. While I was in total agreement with others experiences such as "random height changes are usually driver pack", the engineer in me wanted to prove it !! Bottom line is most faults are either exactly as per the HowTo, i.e. either Leaks, Leaks or the usual LR connector faults !!

Given the slow data rates, it would be more useful if Nanocom could be set to only log the values we actually need ! I will raise this as feature request on their forums when I get a minute. Maybe also a feature request for EAS Unlock ?

Pete
Click to expand...

The reason the valves open is as i stated in post before yours.
 
Yes, as I looked at the braking effect it became obvious some values happened a little out of kilter so obviously some sort of rounding issue. It doesn't show all valves so there could be some other equalisation going on.

Have to agree there are limitations but I also think it is very useful as it is, especially in general terms. I think you could pick up a leak or weak compressor on here before the symptoms become physically apparent.

I've also been playing with the EDC fuelling trace but that can wait until another day. In fact I need to contact Blackbox first and try and work out just what some of it is supposed to mean.

I wonder if there are revisions to the EAS software across the years or if you can even "upgrade" it. Presumably would require pulling the chip off the board.

I'm guessing the Nanocom is really something like an Aduino running Linux with the software sat on top? Presumably there's a limit to the capability of a £20 processor? If it could Bluetooth to my phone in real time that'd be useful!
 
pwood999 said:
I guess we are typing at the same time !! just edited after reading yours !!

Pete
Click to expand...

Yep the car levels to the weight of the driver, a six stone weakling may not make a lot of difference but someone who is eighteen stone would. So there is more pressure in the O/S bag than the N/S. So when the valves open to equalise the axle N/S goes up O/S goes down. When the brake is released and car moves off the N/S will drop and the O/S will rise to level the car. That is why it is more important to get the front as level as possible when calibrating than it is to get the rear perfect. If the O/S has a little more pressure (slightly higher) than the O/S before the driver gets in, the axle equalisation can be amplified and cause what appears to be a suspension dance in stop go brake on brake off edging along traffic.
 
Had to replace the alternator when I got the car. My breaking in to RR ownership when it didn't even make it home before breaking.

Plus, mine's a DT with very little electrickery in it and yours has every bloody gadget known to the 20th century in it. Those 8 cylinders must draw some watts too.
 
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