Do not expect EAS to work off road on D4

[roamer]

Has anyone with a D4 noticed that if you raise suspsnsion from access to offroad, then lower it and then try to go back up it will take up to 2mins to raise, or more if compressor overheats.
Had mine to dealer said needed recalibration, made no difference, waited 3weeks for new compressor, made no difference.
They tested 3 other car in showroom all the same,so they got on to LRA,their answer that must be what they do now.
This in the sand with the 40k/h limit and suspension going down makes the car useless and unfit for its advertised use.
I had a D3 before and it do not do this (ie several up & downs before slowing)
Could other D4 owners please check theirs out, best to know before it ploughs it self into the sand because the rear still goes up quickly which pushes the front straight down.
Will also be a problem if you have just selected offroad and bottom out as extended hieght will take 2mins to raise, a Toyota will have pulled you out by then.

Cheers Ken

[Dingmark Jim]

Yet another reason to use shortened suspension arms offroad. Thanks for the "heads up" on this. I'll let you know if my D4 does the same thing when it finally arrives here.

[Graeme]

After having to leave mine in access height last night due to supposed overheating of the compressor, thismorning it still took quite a little while to start to raise the rear. I stopped after driving off due to the rough ride to discover the front still hadn't started to raise, which took another minute or so to raise. I'll remove the compressor cover to find out if the compressor really is overheating or something else is wrong. I feel that it should have risen much more quickly thismorning.

[isuzurover]

Can you replace the EAS compressor with an ARB compressor???

Or install an ARB and an air tank, and plumb it into the EAS system?

[Graeme]

With my vehicle having sat at on-road height for 2 hours, I removed the compressor cover to be able to hear when it was running, started the engine and left it idling. The compressor did not start. I selected off-road height which occurred very quickly but the compressor ran and ran and ran for several minutes. There was a pressure release at the same time that it stopped, so maybe the over-pressure protection triggered the compressor to stop. The compressor head got way too hot to touch probably about 1/3rd of the time from when it started to run. I selected on-road height (the compressor did not start) then off-road again whereby the compressor ran and ran again. This time I returned to on-road height before the off-road height change was completed (up light still on) and the compressor stopped. I selected off-road height again and the compressor ran for a very long time again, but this time the rear was slower to rise then the front took quite a long time. No error messages were issued.

I returned to on-road height and will try off-road height later today and note whether the compressor again runs for a long time.

I suspect a programming error in the revised suspension ecu that is not stopping the compressor whilst in off-road height until the over-pressure limit is triggered, thus prematurely overheating the compressor head.

[Graeme]

After a bit more investigating, I don't think there's anything suspicious about off-road height. My vehicle is only getting 12.06V across the pump's connector so there's a fair bit of voltage drop. The earth appears to run all the way to the front and its loosing 0.3v compared with the chassis, so an additional earth could be provided to make the pump motor more efficient. There could be a restriction between the pump and the tank that's making the pump work too hard, or it could just be an undersized pump. It reminds me of some tyre valves that require very high pressures to open whereby the tyres inflate ever so slowly.

The slow to rise is due to pump excessive heat inefficiency and the overheating messages are real. I don't know if its operating as it should but I hope not.

[isuzurover]

The slow to rise is due to pump excessive heat inefficiency and the overheating messages are real. I don't know if its operating as it should but I hope not.

Air compressors will always get quite hot due to adiabatic heating. It may be completely normal???

[Graeme]

Yes, I accept that the heat may be normal although the slow rising hopefully is not.

As the D3 WSM shows that higher temperatures are allowed for the motor and pump head when lifting compared with reservoir filling, its possible that the D4 logic has accidentally been modified to not have the reservoir valve closed whilst pumping during lifting. This would account for the inappropriately slow lifting once the reservoir pressure has been depleted. A diagnostic hookup would hopefully reveal whether the valve was open or not. Alternatively, the valve could be faulty and always open. I suspect that unplugging the reservoir valve electrical connector to isolate the reservoir would cause the ecu to suspend changes, but I might try it anyway, not that it would prove anything if the valve is faulty.

[VladTepes]

Can you replace the EAS compressor with an ARB compressor???

Or install an ARB and an air tank, and plumb it into the EAS system?

That would do wonders for the warranty.....

[Graeme]

I was able to unplug the reservoir valve electrical connector without any error messages and the tank was isolated by this action.

Perhaps there is an unintended obstruction somewhere between the pump outlet and the reservoir valve block outlets. As it is, the system has insufficient capacity. I observed that
1. There is insufficient capacity in the tank to fully raise both the rear and the front from on-road height to off-road height just once.
2. The pump has insufficient capacity to speedily complete the lift of the front the first time, let alone subsequent times.
3. The pump head and motor get hot quite quickly and the pump gets less effective the longer it runs, as shown by the decreasing raise rate of subsequent operations.

It might be useful to do a direct D3/D4 comparison to determine what, if any, differences exist. Perhaps a new compressor, dryer or valve block has been used.