There seems to be an issue with the compressor on my SR8. The compressor itself works whenever power is put to it manually, but it doesn't charge up itself.
There is power and earth coming to the sensor on the end of the unit. There is also power coming to the relay on the left-hand side, located just above the radiator, which is connected to the compressor pump. The relay itself works.
The sensor on the end of the unit appears to give a reading rather than switching the compressor on and off, so I suspect this reading goes back to the main ECU for processing and then it in turn activates the relay. It does seem overly complicated if this is the case.
I suspect the sensor is faulty, has anyone experience in this area? It also appears to have taken a nudge at some stage, as the black connector is slightly angled. Does anyone have a source for a new one?
Hi Stephen,
I don't think the ECU does the deed -- I think the "sensor" is actually a trinary pressure switch that activates the relay when the pressure drops below a certain level and deactivates it above a certain pressure. I have one that was working when I removed it when I converted my car to a MoTeC ECU, but it has a different connector. It might work with some connector wiring on yours.
Hi John,
Thanks for your reply. A known working sensor may help to solve this. What is confusing me is I've checked continuity between the switching pin of the relay (negative switched) and any of the connector pins going to the sensor.
There doesn't seem to be a connection, which may indicate a fault in the loom, or alternatively there is layer of control between two components.
Hi Stephen -- right, so if it's a trinary switch, then the lack of continuity is the the problem. An easy to way to test it is would be to check voltage levels going/coming to/from the sensor/switch as you pressurize the tank via external 12V source. If one of the pins goes to ground/earth between 6 or 8-10 bar, then you'll know that pin should be connected to the relay.
If it's a sensor, you'll be able to sort which wire is the sensor output (either ranging from 0-5v or 0-12v), rather than an open-earth-open behavior.
Of course, a consult with Radical would probably sort this quickly. It's getting their attention that's difficult sometimes.
There are three wires going to the sensor/switch. Live (12v) , earth and a yellow wire. I measured the voltage on the yellow wire as the pressure increased, and there was no difference throughout (0.15V).
The control wire going to the relay is the orange wire, whereas the sensor/switch output is a yellow wire.
It looks like a dud sensor/switch, but we can't tell which of the two it is.
If it's a sensor - one would have thought that the lower the pressure in the tank, the lower the output voltage, so the compressor should actually be turned on with the sensor showing such a low voltage.
If it's a switch - why are the wires two different colours, and not connected...
The thing I learned on my older SR8 (the 2007) is that you can't trust the wiring as being original. I found multiple wiring hack jobs in that car.
Is it possible that the orange wire is supposed to be connected to the yellow wire? Maybe it was disconnected since the voltage from the sensor/switch never went to open and the compressor wouldn't shut off?
If its Life controlled paddle shift download the engine data.
As long as the correct config has been programmed you should be able to see the gear system pressure to see if the ECU is seeing the pressure.
You should also be able to see the GSP control, to tell you if the ECU is trying to turn the compressor one.
If your unsure download the data and send it through to me and I can take a look for you.
Dan makes a great point: does the car have a Geartronics gearbox controller or is it Life controlled?
He's right on the money - the car is an early SR8 (Gen 2), so has the Geartronics system.
Were going to swap the sensors around and plug into the Geartronics ECU to see what's happening.
I'll pick this up at the end of the week when we come back from a short break! Thanks to all.
It turns out that the the Geartronics unit had some water ingress and has now been repaired. I must say that there was a quick turnaround from Neil @ Geartronics, who also upgraded the firmware at the same time.
Now after plugging into the Geartronics unit, we have insight into the various sensors and actuators which the ECU sees/controls.
It's just arrived back, so hopefully by the weekend we will have made some good progress.
Hey Stephen,
That's great news. How did you get in contact with Neil? Are you in the UK?
My 2009 SR8 has a Geartronics controller, and I'll bet it could use a firmware upgrade too...
John
I think one of the pins on the connector for the pressure sensor needs replaced, or given a little squeeze, I'll hopefully get that sorted soon.
Yes, I'm in the UK. Best send an email to Geartronics and I'm sure he'll help you. There should be a little sticker on/in the GCU with the firmware version on it.
As suspected, one of the pins required a little squeeze - I had noticed when the wires on the back of the connector were moved, the values changed on the software.
Also the pressure sensor required replacement, all seems to be working now!
Great to hear that you got it going again!
