which wire for obd connection

[gazza345]

hi, i was wondering if any of you guys know which wire i need to connect to on my obd socket to keep the fuel trims in check??? i don't know which connection type my car uses, the car is a 2008 1.6 astra with the new from 2008 1.6 xer engine, the system is the bigas sgis-n up to 190hp system, in the paperwork it states that i should move the grey and voilet wires from black connector pin 7c and 8c respectively to pin 6c and 8a, thing is my car only uses the purple wire and the grey wire is un used, does that mean i only need to connect the purple wire to the new ecu pin??
Thanks, Gary

[tommo2009]

you dont need to move any wires on the OBD connector, and the grey and purple wires are for the lambda connection. It should only have the purple one connected.
How old is the system, If memory serves me correct, the OBD wire is a green and orange one in the LPG loom.

[gazza345]

hi mate, the system is brand new and with the option to connect to obd to keep fuel trims in check, its only installed about a wk, i done the course in tinley tech few wks ago, i have the lambda connected to the purple wire but like the idea of the ecu keeping things that little bit closer to perfect,(if thats possible!!!)
Thanks,Gary

[Tubbs]

I think you are confusing yourself with the manual and what you actually have in the wiring loom mate.
It used to be the case that you need to move a couple of pins about, using the purple and grey wire as they where there and unused. However the aeb looms generally come with the obd wires i suppose its possible that you have an old loom. You should have a sheath with three wires in it. On a 4 cylinder there are two sheath's one with the can wires and one containing the green wire for k line.
So do you have 3 spare wires ? You should have a green, a green and yellow traced and a yellow with a trace. I cant actually remember what colour trace it is off the top of my head. Its all written on the wall in the workshop.
So k line, (green wire) connects to pin 7
The other 2 wires, green and yellow traced are for the can bus pin 6 and pin 14, they are opposite each other on the diagnostic socket.
Hopefully i have this the right way round ! Hopefully someone will correct me if im wrong !
The yellow to pin 6 and the green (both traced) to pin 14.
A 2008 car will be can bus and not k line i would say.

[gazza345]

hi Tubbs, i may be wrong about this but i thought this was a fairly new function of the aeb ecu?? pls see the attached pics, this is the instruction booklet that came with the bigas kit, it is a seperate booklet to the main instructions, Thanks, Gary

[Tubbs]

Its not that new anymore mate. The system i fit has it all built in, so i am presuming its just a standard part of the loom now. Mind its been a good while since ive fitted bigas. I know the king has the wiring already there and emer for example.

[Gilbertd]

It looks to me like the older loom didn't have the required wires in it so they used the lambda wires instead on the assumption that you don't actually NEED them to be connected to the lambda sensor. Presumably later looms have the additional wires in there.

[Tubbs]

Thats right they did, but i would have thought that bigas had changed over to the newer type, oval plugged aeb loom by now ? Maybe not.

[gazza345]

Well the loom i got with my kit has the 8 pin rectangular type diagnostic plug, so what do you suggest guys, should i connect the front lambda to the ecu in the way shown?? Sorry bout all the questions but this is all new ta me, i'm learning all the time!!
Gary

[Gilbertd]

It may take a bit longer but if I was installing it I'd add the additional wires from the ECU to the obd socket and leave the lambda wires connected.

[gazza345]

Hmm never thought of that, as i said learning all the time!! i think the map sensor came with spare crimp connectors in the box so i can just use them and make it nice and tidy, thanks again guys, this really is a fantastic place to glean real world info and advice!! Gary

[Tubbs]

Gary, sounds lie you need to shunt the pins over. You will need two wires for the can bus. Do you have two sets lambda wires ? one purple and one grey and one purple/grey with a trace. If you want to keep the front lambda to connect then use the post cat (traced) wires maybe ?
Just a thought.

[gazza345]

Hi Tubbs, yeah i have just connected the front lambda (violet/grey)to the ecu via the violet wire leavin the grey wire disconnected, the 2nd lambda (violet-black/grey-black)is not connected at all so will prob move these wires and use them to connect to the obd socket.

[gazza345]

Hi guys, i know this thread is a bit old but i had an unrelated prob with my astra that had to be sorted before i went any further, damn thing was oiling up the plugs and was using oil big time, turns out that the pcv valve in the rocker cover was goosed, cost£162!! Anyway with regards the obd connection, my astra has the petrol ecu perched on top of the inlet manifold so instead of having to take wires from the engine bay into the car to the obd socket i used a multimeter buzzer function to try to trace the circuit by disconnecting the big multiplug at the petrol ecu and with the other end in the obd socket, i have found what i believe is the two can wires but they are not the same colours as the wires at the obd socket end, the can h wire at the obd socket is green but the wire at the petrol ecu is pale blue and the can L at obd socket is white but at the petrol ecu it is green, can this be correct or am i getting an incorrect reading from another source??
thanks, Gary

[Tubbs]

Gary, go back to the diagnostic socket mate. Best not risk it for the sake of running a couple of wires in.

[birkopf]

I have a question. I have Stefanelli SIS+ in my car and need a socket for it. I have 16 pin socket in the "ECU". There should be loom to 4pin. Could you have a look at this topic?
http://www.lpgforum.co.uk/viewtopic.php ... 871#p83871

If there is a loom can I buy it or if you have one could I borrow ?

If there isn't can use small small jump cables and connect to those 4 main pins? Would it work ?

[Gilbertd]

This thread isn't relevant to you at all. He has a Bigas system which uses an AEB ECU so the plugs and looms will be completely different.

Yes, as you only need the 4 wires to go to your interface cable you only need to attach 4 wires to the ECU, your challenge is to find out which of the 16 pins you need to attach your 4 wires to.