Corsa-B.uk - Vauxhall, Opel and Holden Corsa B Owners Club

Hello folks.

My first post here, I guess I should introduce myself briefly. Somebody told me about this forum and said this is the place to go for any corsa-specific tuning and repair knowledge. I am into old cars, specifically rods and drag cars. I have never even been inside a Corsa, let alone owned one, so it's safe to say I know absolutely NOTHING about them at all. However, having built a few engines here and there (inc racing, and specifically drag), I know my way around engines pretty well. Me and my buddy occasionally get pretty good 1/4 times out of old beetles and things.

Anyway, the reason I am here is because, long story short, I decided to put a 1.0 engine in the back of a old Fiat. I won't bore you too much with the reasons, but basically for a while now we have been trying to build an old car with a modern fuel injected engine, because of their long service intervals and good fuel efficiency. The Corsa engine is small enough to fit, 4 cyls won't fit, they are too long, and a V6 is really fun but kind of defeats the point of a small fuel-efficient engine, but someone at the garage next door had a 1.0 corsa and let me measure the engine in it and stuff, and It will fit, literally with about 5mm to spare. A visit to the junkyard reserved a donor vehicle, a corsa B from like 1998 or 1999, with major accident damage, but with a good engine.

So, having roughly taken care of the gearbox and clutch (some machining to the flywheel, mix and match clutch parts and a adapter ring), now I need to get to know the engine, and specifically the ECU, and I am wandering if you could help me out with this.

Having never used Ecotec (it is basically ecotec with one cylinder missing, right? or not?) ECUs or injection systems before, I don' know their specifics. I did order a manual for a Corsa B, hopefully it will have a wiring diagram in it, but for now I am trying to work out the basics. As far as I understand, the ECU will not fire the engine unless it's connected to:
-The engine sensors, injectors, coilpacks etc, obviously
-The instrument cluster
-The fuel pump control module thing (is that just a relay?)
-The ignition switch.

All the engine sensors/fittings are staying of course, but I have a few questions about the rest. Basically, how to make the ECU think it's in it's native car, when it's actually in a 40 year old Fiat.

1) The fuel pump. Somebody told me that the ECU will come up with a major fault ('major' as in completely won't work, not just limp mode) if it's not connected to the fuel pump control box. From what I gather the fuel pump box is just a glorified relay that fires the fuel pump when the ECU tells it to. Is this right? Does the ECU get any inputs from things like accelerometers/crash sensors or something to tell it when to kill the fuel pump in the event of an accident? I was thinking of keeping the fuel pump control system from the Corsa, depending on what sensors etc it needs.

2) The instrument cluster. Do I understand correctly that at least some of the dials (fuel gage and temp? And speedo?) are a stand-alone part in the instrument cluster and are not related to the ecu? So, what parts of the instrument cluster are critical to the operation of the ECU? Is it possible to confuse the ECU into thinking it's connected to the instrument cluster when in fact it's not?

3) The ignition switch. I heard that the ECU has a built-in immobilizer system that has a sensor in the ignition lock, and has to be matched to the chip inside the key. How does all that work? I won't be using the ignition switch from the Corsa, so is there any way to modify the ECU to disable that whole system completely? I bet inside the ECU there is a pin somewhere that's held hight or low to indicate the state of this system (either immobalized, or OK to run). Is it just a matter of finding that pin and making it either permanently high or permanently low? I know in many ECUs, the immobilizer just holds one of the input pins of the main processor high, so taking the ECU apart and cutting that track and connecting it to v+ in effect bypasses the whole circuit, but iv never had anything to do with Corsa ECUs specifically, so don't know.

4) Is there any other subsystem in the Corsa that the ecu needs to be plugged into, otherwise it will refuse to run the engine? If I am transplanting it into a completely alien to it vehicle, what else will it need with it?

Sorry for the long questions, I guess it's always difficult doing something for the first time. I hope somebody can offer some opinions on this tho.

Thanks very much.

1) if you look at any corsa looms you will see the ECU has a small square plug with like 9 wires on it, and this is all you would have to worry about. the ecu wont show a fault if theirs a problem with the fuel pump, it just wont start, end of. as the corsa pumps is literally just a relay to a pump with two wire to make it work. theirs no magic trickery on them i dont think?

2) the instrument cluster hasnt got anything to do with the ecu at all, the car will run without the dials. its the corsa c that wont run without the instrument cluster.

3) only on some cars (most) they had an immobilizer system check around your key switch with the trim removed, it looks like a donut around the ignition switch with a small box size of credit card attached to it, this is the sensor, the chip inside the key is related to the ecu itself, if you do have an immobilizer on your car, then i think you would have to get the immobilizer on the ecu removed / blocked, there are people that can do this but i dont know anyone of the top of my head.

4) nope. there shouldn't be alot else at all i dont think? try and look for that small plug about 1" square. thats if the 1L loom is the same as other corsa's, as these 1Ls have the ecu in the scuttle i believe, where as all the other corsa's have them on the right hand side of the footwell behind the plastic cover.