Greg_S S2 Coupe 20+ years going strong

[Greg_S]

Finally had an opportunity to check the s2 out again and been retracing steps today. So far tested relays 1,4,5,7,8,10 as we have been working through. I've traced back through to the fuel pump relay which the relay operates fine, however the Ecu isn't switching it on.

I'm trying to check how the Ecu is powered as it doesn't appear to have a feed. Which circuits provide supply to the Ecu?

[Greg_S]

I've been going through the schematics again this morning. http://www.s2central.net/S2_Schematics/B/B73.PDF

I'm getting a bit screen blind though. Can anyone tell me where bus 15 is fed from and where it connects. I'd like to avoid taking the fuse box out to check underneath as I'm more likely to disturb more connections in doing so. I'll mark down what voltages and states I'm getting on the fuel pump relay next.

I may have answered my own question. The ignition switch connects to track 15 (A2) up from the dash wiring loom. http://www.s2central.net/S2_Schematics/D/D44-07.pdf

So this is where I should focus some more effort to verify the connectivity

[Greg_S]

I had 5 mins to take another look this afternoon and started with the fuel pump relay and removed the cover. It isn't operating on the ignition to activate it. When manually closing the after run pump amongst other component Spring it o life, but still won't start. It appears the small terminal has 12v supplied to it, I'll have a check through the wiring diagrams this week to try and work out what to look at next. Also setup a couple of mouse traps just incase

[Greg_S]

I'll double check but the whole immob loom was off the ignition, I'll make sure though

[Error404]

Often the power supplies off terminal 87a of the fuel pump relay are severed with an immobiliser loop, so check that. A problem there would explain the issue.

[Greg_S]

Page 35 http://www.s2central.net/S2_Schematics/ABY_Wiring.pdf shows 87a with right colours for the 15a fuse on "moteur" and connects to track 46. Still tracing back ignition switch.

Looking at wiring diagram again it relies upon the fuel pump relay J17 being energised.

Ive tracked down the wiring diagram for ignition switch on Paul's site http://www.s2central.net/S2_Schematics/D/D44-07.pdf

Does D50 (ignition switch) map to this schematic starter B50?

http://www.s2central.net/S2_Schematics/B/B73-01.pdf

As starter is running I'm going to discount that circuit.

Next up is rail 76 which connects to a voltage regulator, voltage doesn't appear out of order though.

Need to trace where 132, 197, 22,190, T10/5 and that the x relay is working

[Greg_S]

I've been taking a look through the quattroworld wiring diagrams and Mike's site.

At present I'm trying to trace where the red/black and black cables from ignition switch connect on to. And second where the the 15a fuse is fed from

[Greg_S]

I decided to start with the ignition switch this evening which is also where the immob is connected. Pin 15 black is a switched live and I have verified that the immobiliser is switching the return line of this circuit.

Also it is connected to 50 on ignition switch. Again I've verified the immobiliser is switching this circuit in its return line.

Next up I was going to trace back from the 15 amp right hand fuse "moteur" fuse which isn't going live and try find it in the loom. Looks like one is green and the other is green/black. Will see if I can find wiring diagram from some of other posts.

It still could be a poor solder joint or broken wiring from return of immob on ignition switch too

[Greg_S]

Not a bad idea, i'll see if it is getting the right supply to it also

[newsh]

Just wondering if it could be the ignition switch, I think there may be a failure mode where it cranks but doesn't fire up? Not sure, I know I had to replace mine but don't remember the exact symptoms.

[Greg_S]

Perfect, that answers my question. Will get on with tracing the wiring next. Thanks for the help all

[newsh]

Ok on my car, I just took the orange cover off the 2 motor fuses. Looking into the fuse box from the front of the car. Left one is powered all the time, right one is powered only when ignition switch is on.

[Greg_S]

I'll start poking about this week, its not too bad to get to the immobiliser, just get the use S2 crick neck and sill back ache

[newsh]

I'll go and meter the 2 fuses now Greg.

On both mine and Keith's the fuel pump wire was cut into near the ECU.

[Greg_S]

Would be worth knowing the both of the "moteur" fuses should be live when the ignition is on?