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Discussion Starter #1 (Edited)
Well just as soon as I fix one weird and difficult-to-trace problem (fuel pump circuit), something else rears its ugly head.

I've been fixing some wiring on my S3, under the dash on the driver's side. Looks like a mouse got in there or something, and a previous owner repaired the damage using insane lengths of randomly colored wire, and cheesy little crimp connectors. Anyway, I've "re-fixed" some of the wiring (solder and heat-shrink), tonight I thought I'd fire the car up to make sure I hadn't crossed any wires so far. The engine runs fine, but my cold start injector is no longer getting voltage!!!! It looks to me like all the wiring for the thermo time switch and the CSI goes to the two large bundles that run along the passenger side of the car, and I haven't touched those.

I actually replaced the CSI a few weeks ago after determining that it was getting voltage (volt meter on the connector) but not opening, and this made cold starts a LOT better. Now it takes forever to start and the connector doesn't even get voltage. :( I checked the TTS and at the moment I can't say for sure if it's ok (engine is a little warm yet, and TTS shows around 65 ohms), but I did actually unplug its connector and short the terminals of the connector together, since (as I understand it) this is essentially what the TTS does when cold, correct?

I don't understand what could possibly have happened. All my wiring work has been on the driver's side under the dash. I did cut the pink-white wire running from the fuel pump relay to the inertia switch (had a short in it) but looking at the diagrams, I don't see how this could possibly have anything to do with the CSI.

This thing is trying to drive me loony!!! HELP!!!!!!!!!!!!!!!!!

EDIT: A little extra info.....I just measured across the CSI plug and it's a dead short while the TTS is plugged in, and they both show a short to ground. If I check for voltage, I get about 9.3 volts during startup on BOTH terminals. Each terminal on the TTS connector shows a connection to a terminal on the CSI connector. With the TTS unplugged, the short is gone, and one terminal on the CSI connector gets voltage on startup, the other is dead/open. If, with the TTS still unplugged, I connect one TTS terminal to ground (the one that shows a connection to the "dead" terminal on the CSI plug), the CSI opens while starting (and presumably the entire time the engine is running, until I break the circuit). So it sounds like I have something weird with the way the TTS connects to the CSI......???
 

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If it'll help here's a snip from one of PapaJam's excellent wire diagrams:
(I not sure what is meant by 'start signal' - perhaps the ignition switch?)

Note there are four wires shown - one of the other two goes to terminal #50 on the drive relay, the other to the FI ECU.

HTH
 

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Trained (ex)Professional, , 1953-2018 RIP,
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(I not sure what is meant by 'start signal' - perhaps the ignition switch?)
Yes, the start signal is from the ignition switch terminal #50. It is hot when the key is in the start position only (the starter solenoid is energized by this same circuit).
The CSI is powered from the start signal and grounded through wire #46 at the TTS. The TTS provides a circuit to ground when A) engine temp below about 95F and B) the bimetallic strip in the TTS closes the ground circuit. A hot engine does not require the additional fuel provided by the CSI so the TTS ground circuit opens on temperature. Hence, the CSI is not energized. If a cold engine is cranked for more a few seconds (dependent on engine temp), the bimetallic strip in the TTS opens the CSI ground circuit to prevent engine flooding.
 

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Discussion Starter #4 (Edited)
Thanks, that's some info I really needed....I do have the diagram, but didn't know where that end of the circuit went. I think tonight I'll do some poking on the wire coming off terminal #50 of the ignition switch and see what I can find out....maybe I have some shorted wires somewhere.
 

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Discussion Starter #5
Hmmm ok, I poked around my wiring a bit and find nothing amiss. Looking at the diagram and reading papajam's post, I understand it this way:

1. Terminal #45 of the CSI is connected to #50 of the ignition switch, this is where the power comes from.

2. Terminal #47 of the TTS just goes to ground

3. Terminals #46 of the CSI and TTS are connected, this is how the CSI gets its ground.

Is this correct? Using this info, it would seem that instead of going to ground, terminal #47 of the TTS is getting power somehow. If it's shorted to the wire going to #45 of the CSI, this would explain why each terminal on the TTS is currently showing a connection to a respective terminal on the CSI, and would also explain why I get voltage on both terminals of the CSI on startup.

So it looks like I need to start tearing into more wiring....ugh. I don't even know where the TTS grounds at, guess I'll have to rip up the bundle and trace it. :'(
 

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Discussion Starter #6
Huh??!?!?!!!?!?!!!!!!!!!

OK, back again...I've done an admirable job of butchering the nice original wiring harness up in the engine bay, and some back by the injector ECU. Now I've found something totally weird.

The CSI and TTS each have a green-gray wire going to them, both wires disappear into the harness. Then there's a blue wire that connects a pin on the CSI to another pin on the TTS. So it would seem that one of the green-gray wires should be grounded, the other should get the start signal, right? Well, such is not the case. On the passenger side, behind the dash, I found FOUR green-gray wires. They ALL GO INTO A ONE-PIN CONNECTOR. So they're all connected to each other. They connect to two purple wires that seem to disappear into the harness that runs along the passenger-side floor, or perhaps one that goes over to the driver's side under the dash.

To verify that two of the green-gray wires were the ones going to my CSI and TTS, I unplugged the connector. Now none of the pins on the CSI or TTS short to ground, nor do they get any voltage on startup. Before, one pin on the TTS shorted to ground, and one pin on the CSI shorted to ground (but it was the pin that's supposed to supply power to the CSI, NOT the one the TTS is connector to...so on cold startup, both CSI pins shorted to ground).

If you read the diagram at face-value, it does seem to indicate that both ends of the CSI-TTS circuit go to the same place ("start signal"), but this doesn't make any sense!!!!!!

Here are the heavily populated connector ends:
http://www.theplaceofcoolness.com/pics/alfa/weird_connector.jpg

And the CSI and TTS (you can see the wire going between them here):
http://www.theplaceofcoolness.com/pics/alfa/csi_tts.jpg

I hate to keep crying to the board, but I've been chasing this thing and scouring diagrams for 2 days and this last development has set me completely back to square 1 (and the entire FI system is absent in the FSM schematics, aside from very basic layout drawings). I don't know where to go from here, short of ripping out the heater core, the rest of the ducts, center console, carpet, everything, and tracing every single last bit of wiring that appears to be even remotely related to the CSI.....I just have no idea what's going on. Heeeeeeeelp!!!!!!!!!!
 

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1. Terminal #45 of the CSI is connected to #50 of the ignition switch, this is where the power comes from.
Correct.

2. Terminal #47 of the TTS just goes to ground
NOT correct. Terminal #47 of the TTS and terminal #45 of the CSI share a common power source; ignition switch terminal #50.

3. Terminals #46 of the CSI and TTS are connected, this is how the CSI gets its ground.
Correct
.....................

The TTS provides a ground for the CSI when the TTS is closed. The ground is provided internally through the body of the TTS directly to the engine via the threads on the TTS. There is no ground wire; the body of the switch IS the ground.

Try running a jumper wire from CSI terminal 46 to ground. If the CSI opens during cranking, check continuity (with a cold engine) between TTS terminal 46 and ground. If no continuity, replace the TTS.
 

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Discussion Starter #8
OK, well now after reconnecting the thingy behind the dash on passenger side, and re-soldering the lead I had cut on the CSI, it seems to have magically repaired itself.......I checked the TTS and it was showing a short to ground on one terminal, other terminal was showing about 33 ohms of resistance to ground, cold....sounds about right I guess?

But unfortunately I really screwed up while reconnecting the hoses.......see my new thread.......
 
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