Hi chaps,
I think i've got this sussed from the DTA wiring diagram but I wanted to double check.
I've got a 0-10 bar VDO pressure sensor that I plan to use for fuel pressure. It's got two terminals because it's intended to be an oil pressure sensor with an additional terminal for a low pressure warning light.
The "WK" terminal appears to be for the warning light. "G" i'm assuming is the signal wire (Pin 33 in my case for an S40 ecu). Then i'll need to splice in the 5v signal feed with a 560 ohm pick up resistor (Any idea where to get one of these?). Lastly the sensor will be earthed through the NPT thread in between the sensor and the adapter.
`
VDO pressure sensor wiring
- mefmotorsport
- Posts: 543
- Joined: Mon Aug 01, 2011 6:45 am
- ECU Model: S100 Pro
- Distributor: Mefmotorsport
- Firmware Version: 79
- Location: Merseyside
- Contact:
Re: VDO pressure sensor wiring
OK, you've got the wrong sensor really, the one that DTA recommends has 2 terminals, the resistor of the sensor goes between the terminals and is isolated from earth. the sort you have has a switch to earth on one terminal and the sender to earth on the other. It's not ideal as you'll be tying the DTA sensor ground directly to the engine so you could suffer with introducing interference signals up the ground wires. Also have you checked the sensor resistance, it should be around 10 ohms with no pressure and go up to 100 and something with 10bar. If your's has a different resistance then you'll need a different resistor or will have to write a new calibration table. You will get a 560 ohm resistor from maplins or somewhere similar. I put my resistors at the ecu connector end to save the extra wire to the sensor!
Martin
Martin
Re: VDO pressure sensor wiring
Pants! I was going to earth the sensor back to the ecu through the fitting that screws into the dash 6 adapter. My fuel rail is plastic so it wont be earthed to the engine. That's how VDO's website had it. Although I guess they just earthed it back to the engine.mefmotorsport wrote:OK, you've got the wrong sensor really, the one that DTA recommends has 2 terminals, the resistor of the sensor goes between the terminals and is isolated from earth. the sort you have has a switch to earth on one terminal and the sender to earth on the other. It's not ideal as you'll be tying the DTA sensor ground directly to the engine so you could suffer with introducing interference signals up the ground wires. Also have you checked the sensor resistance, it should be around 10 ohms with no pressure and go up to 100 and something with 10bar. If your's has a different resistance then you'll need a different resistor or will have to write a new calibration table. You will get a 560 ohm resistor from maplins or somewhere similar. I put my resistors at the ecu connector end to save the extra wire to the sensor!
Martin
Sounds like it would be easier to get a new sensor.
-
- Posts: 602
- Joined: Fri Dec 04, 2009 1:45 am
- ECU Model: S80 Pro
- Distributor: DTA UK
- Firmware Version: 73
- Location: Pennsylvania, USA
- Contact:
Re: VDO pressure sensor wiring
It would be Martin is right. What do you budget for a pressure sensor? I have been using a Kalvico (AEM) transducer on oil and fuel pressure and love them.Ponk wrote:
Sounds like it would be easier to get a new sensor.
1992 700RWHP Pump Gas BMW
Re: VDO pressure sensor wiring
Oh well. It was an ebay bargain so I can't complain too much.Jon K wrote:It would be Martin is right. What do you budget for a pressure sensor? I have been using a Kalvico (AEM) transducer on oil and fuel pressure and love them.Ponk wrote:
Sounds like it would be easier to get a new sensor.
Budget is as little as possible really. Can anyone link me to the right sender on ebay? Is £50-60 the going rate?
- mefmotorsport
- Posts: 543
- Joined: Mon Aug 01, 2011 6:45 am
- ECU Model: S100 Pro
- Distributor: Mefmotorsport
- Firmware Version: 79
- Location: Merseyside
- Contact:
Re: VDO pressure sensor wiring
Well it's OK if its plastic and not earthed but the main problem will be the resistance of your sender I think.Ponk wrote:Pants! I was going to earth the sensor back to the ecu through the fitting that screws into the dash 6 adapter. My fuel rail is plastic so it wont be earthed to the engine. That's how VDO's website had it. Although I guess they just earthed it back to the engine.mefmotorsport wrote:OK, you've got the wrong sensor really, the one that DTA recommends has 2 terminals, the resistor of the sensor goes between the terminals and is isolated from earth. the sort you have has a switch to earth on one terminal and the sender to earth on the other. It's not ideal as you'll be tying the DTA sensor ground directly to the engine so you could suffer with introducing interference signals up the ground wires. Also have you checked the sensor resistance, it should be around 10 ohms with no pressure and go up to 100 and something with 10bar. If your's has a different resistance then you'll need a different resistor or will have to write a new calibration table. You will get a 560 ohm resistor from maplins or somewhere similar. I put my resistors at the ecu connector end to save the extra wire to the sensor!
Martin
Sounds like it would be easier to get a new sensor.
I just had a quick look at the pressure sensor scaling in the DTA software for the VDO 10bar sensor, a quick calculation shows that at zero pressure the 0.088V relates to a 10 ohms resistance of the sensor, at the top end, 10 bar, 1.237v relates to 184 ohms so that is the range you should be looking for from your sensor.
Of course if you know the resistance range of the one you have (or test it with compressed air and a pressure gauge and ohm meter) you could easily build a new calibration chart using whatever suitable pull-up resistor you decide to use. I wouldn't go lower that 500 ohms though as the resistor will start to get hot with low pressure and also you will start drawing considerable current from the DTA 5V rail.
Hope this helps,
cheers,
martin