AHC - Backend drops when loaded (1 Viewer)

[Quade]

I have a weird issue with the ahc

I put 7 people in the car and it sat right down and would not come back up

I emptied car, and then got everyone to get in with engine running and it did eventually raise and stay up

I've also noticed if it fiddle with up and down, it sometimes sits in low, and attempts to come up, and then drops to low again, (unloaded)

Also, If I touch the up and down, the next time I drive the off light flashes for a number of trips
Generally it stops flashing after a day or 2
(as long as I leave heights alone)

I have :
New rear globes
New shocks all round
New rear springs
Oil change
And a mechanic who screwed up some engine stuff so I'm not convinced the work he did on the ahc was to spec

 

[Quade]

Where should the oil level be in neutral?

Its about 2 graduations above max in N

 

[DirtDawg]

Sounds like your neutral pressures are too high. You're overloading the system. Do you have access to techstream? Do you know your current neutral pressures?

Even with the new springs, the extra weight can still overload it. I would look into adding some spacers or the King heavy duty rear AHC coils. They are made for carrying extra weight.

 

[Quade]

Thanks, I rarely put this much weight in, just a family of 5 (3x under 5's)

I lent my tech stream software to mechanic and it never came back... I've given up with him as he introduced more issues so I need to order a new cable (not sure which one supports 64 bit)
There is a mech across town that has tech stream

Does it sound like there is too much oil in system? When it N is above max

 

[DirtDawg]

Thanks, I rarely put this much weight in, just a family of 5 (3x under 5's)

I lent my tech stream software to mechanic and it never came back... I've given up with him as he introduced more issues so I need to order a new cable (not sure which one supports 64 bit)
There is a mech across town that has tech stream

Does it sound like there is too much oil in system? When it N is above max

Do some reading on here man, get familiar with the system. The cable for techstream doesn't matter, it's the software that designates if it's 64 or 32 bit. It is not a circulatory system like brakes or power steering, the tank in the engine bay is only a "holding tank", so as long as there is fluid in there, you've got enough in the system. There's no such thing as "too much" fluid for the system. The only thing too much fluid would do is cause the holding tank to overflow. I would start reading here:

Definitive list of AHC maintenance items

 

[Quade]

Thanks

After more reading, it appears the car was overloaded, we had 7 fatties in the car, and the big guys at the back

I've ordered the cable, I have the software already installed

The curious bit, if I raise to high when stationary , and shake the car, the car drops down to neutral and then the Off light flashes for the rest of the day

From what I read it could be the pump

 

[PADDO]

Thanks

After more reading, it appears the car was overloaded, we had 7 fatties in the car, and the big guys at the back

I've ordered the cable, I have the software already installed

The curious bit, if I raise to high when stationary , and shake the car, the car drops down to neutral and then the Off light flashes for the rest of the day

From what I read it could be the pump

Keep reading as it's very unlikely your pump is faulty - all the pump does is charge the height accumulator and provide augmenting pressure for raising. Its normally off and only kicks in on demand and doesn't run during a lowering cycle. I'd investigate loose/bent height sensor brackets or a failing sensor. Potentially your front sensors are sufficiently misaligned and the rocking exacerbates the misalignment to the point the system is seeing a fault and dropping to N, which is normal behavior. With the flashing OFF you may be able to manually extract a DTC from the system which would eliminate some guess work until you can get Techstream again and do some proper diagnostics. Knowing your pressures at N would be very helpful too, as it's also possible they are so high the system is stressed to the point that it can't maintain a steady and consistent H without going beyond it's designed limits, with the ecu subsequently commanding a lowering to N cycle.