Discussion and questions related to the course EFI Wiring Fundamentals
hey, I have a vw 1.8t engine which has a 3 wire crank sensor, presumably this is a hall sensor?
does anyone happen to know the sensor pin out?
Yes 3 wire is hall type. Is the factory ECM/PCM still connected?
No but I do have access to another car with same engine
Great KOEO (Key on engine off) unplug sensor and using a multi-meter you should see power (12v), ground (0v) and signal (0.5-5v).
With a little hunting on the net you can usually find a factory wiring manual for most popular engines which will have this information. Beyond this the method Shawn has described should get you going.
reason I was asking the original question is, when I was wiring up my dta s80 ecu I was told by someone who runs the same engine/ecu that only 2 of the 3 wires needed connected to the ecu.
I done as he suggested and the car did start with only 2 of the 3 wires connected
this confused me as I was under impression all needed to be connected but it ran so I disregarded it at the time, now I'm going down a completely different route in regards to ecu/wiring so was looking for other opinions and was being lazy by asking if anyone knew the pin outs so I could see if it was infact a hall sensor with 12v, 0v & signal
looked into the crank wiring today and has confused me further
it appears its not a hall sensor as first thought?
the sensor has 3 pins
pin 1: earth
pin 2: ecu pin90
pin 3: ecu pin82
going by pin out data for pin 90 & 82 on the ecu the are basically the same apart from one says the wave form is reversed?
anyone shed some light on which wires id need to connect to a standalone?
ive attached a pic of pin out data for ecu pins
A.c. voltage is inductive type. I believe you have 2 signal wires and the 3rd is the shield. Use the DMM on a.c. voltage on the 2 signal wires with the sensor unplugged and crank. If you see a voltage wire it like a vr type yellow and green negative and positive.
thanks for the reply, I presume you mean connect to the sensor side of the wiring when its unplugged and not the wires going to ecu?
Looking at that info it does indeed look like its a VR sensor, with a 3rd pin most likely for a shield connection. Does the sensor have a metal body? You'll want to determine if the 3rd pin connects to the body of the sensor, and then the block/head in some way when its installedf, as it'll determine where you hook up the shield on the trigger wiring to ground; you don't want it grounded at both ends.
the sensors are plastic, it has a short cable built into the sensor with a 3 pin plug at the end
after looking at another wiring diagram its looking like pin 1 on the sensor is a shielded ground, it connects with the knock sensors and cam sensor shield then they all go into ecu pin 108
leaving pin 1&2 on the crank sensor which makes it a vr sensor?
so whats the correct way of wiring this up to the ecu?
What ECM are you running or going to be running?
I will be running a ecumaster emu black ecu
Sounds like they have used shielded wire on the small section that is part of the sensor, which is really nice, as many VR sensors with flying leads don't! This is a great example of continuing your shielding through a connector too.
You'll need to determine the polarity of the VR sensor, do you have access to an oscilloscope at all? If not, you can do it with a multimeter, there is a section on it in the wiring fundamentals course.
VR+ to pin 8 of your ECU's black connector, Primary Trigger Input
VR- to either pin 38 or 39 of your ECU's black connector, Sensor Ground.
Shield spliced into the ground wire going to pin 28 of your ECU's black connector, ECU Ground. Splice it as close as conveniently possible to the connector.
I haven't dealt with an ecumaster ecu before, so I'm not sure what they have in the way of VR sensor setup parameters or built in trigger scopes, but you might need to observe the waveform on some sort of scope to set up the arming threshold levels.
I'm seeing Primary ignition and Camsyncs. I'm thinking it works as the jz's do and ground out the VR-. I agree with Zac, it's the only way it makes sense to me.
Yeah, I'm more used to ECU's with a dedicated trigger -ve pin as well, but its not uncommon for the vr sensor -ve to be connected to the sensor ground, Link ECU's do it this way too.
so the + side of the sensor will go to the trigger input on ecu, the - will just go to sensor ground pin?
what about the shielding? where do I terminate that?
Splice the into the ground wire going to pin 28 of your ECU's black connector, ECU Ground. Splice it as close as conveniently possible to the connector.
thanks for clearing that up
one last question, whats the difference between the ecu ground and power ground?
Ecu/sensor ground is a ground provided by the ecu (circuit goes through ECU to ground ) e.g. TPS-->ECU-->Engine block/chasis. Power ground is provided to the ECU e.g. Ecu-->Engine block/chasis.
my ecu lists sensor ground which I know is used for sensors, I now know power ground is the one direct from ecu to chassis
so what is the ecu ground used for?
I apologise if I'm sounding stupid, I'm not really ha ha
Nah, its a good question! The different ECU manufacturers also have different ways of denoting things, and pinning things out, it can get a bit confusing. In this instance, I'm betting that ECU Master use the 'Power Ground' pins to dump the current from the injectors, coils, wb02 heaters, or any other moderate current circuit its providing a ground for to the vehicle chassis / engine block and then back to the battery. I'd say the pin it lists as 'ECU Ground' will be the ground the ECU uses internally for its circuitry, the micro's, voltage regs, etc, etc.
Hope that helps :-).
so am I right in saying both power ground & ecu ground should go direct from ecu to chassis?
In that case the "ECU Ground" should be for the ECU to power on. The "Power Ground" is for controls. In that case, yes both have to go to chasis.
that was what I originally thought but just wanted to make sure to save any issues
thanks very much