TimH

iTrader: (11)

ALthough you *may* have headgaskets gone, , that will NOT explain the temperature sensor issue. You need to get that fixed first.

I still maintain that you should not be seeing 12V at the sensor.

Oh, and headgaskets are unlikely to cost you £3k, unless that includes other engine work. £1-£1.5k is nearer the mark, including skimming etc.

lee1981

Hi Tim I completely agree, the guy at scoobyclinic told me the coolant temp gauge issue was happening because of the headgaskets and not a wiring fault, they no there stuff but I cannot get it in to my head how this could cause that fault! they said 3k because they recommend a full rebuild when doing the gaskets.

TimH

iTrader: (11)

You definitely have an electrical fault - even with blown head gaskets you would not see 120C as soon as you key-on.

Is it possible that connectors have got swapped? Coolant sensor connector should be black, whereas (for example) AVCS connectors (which *do* have 12V on them) are blue?

lee1981

Coolant connector is black, the loom is quite tight so don't think it would stretch that far, I think it is an electrical fault too but really cant see where :-(

TimH

iTrader: (11)

Can you tell me which pin you're seeing 12V on? As you look at the front of the connector, the signal side is on the right, and the ground is on the left. Knowing which one is seeing 12V might assist in tracking down the fault.

lee1981

Pic of car as it is now:-(

TimH

iTrader: (11)

lee1981

as your looking at connector the pin on the right which is a black wire with white trace is an earth but when ignition is turned on it goes to battery voltage, the other wire on the left is white and has a 4v feed when ignition is turned on.

lee1981

on the wiring pic you sent pin 2 has a 4v feed and pin 1 has 12v when ignition on.

TimH

iTrader: (11)

Pin 1 should be ground, so that suggests your sensor ground wiring has picked up a short to +12V somehow. Could be a fault in the ECU, or wiring. Just about to PM you.

lee1981

so the wire which goes to map sensor etc is a ground?

TimH

iTrader: (11)

Yes - it's the sensor ground. And if that's at 12V you potentially have not only, perhaps, knackered ECU but may have killed loads of sensors too. Let's hope not!

lee1981

mmm hope not! the strange thing is I am only getting a code for faulty coolant temp sensor, and the wire that is supposed to be an earth is also going to map sensor and injectors too, so you would think it would bring up codes for them too?

TimH

iTrader: (11)

Injectors have a 12V feed for sure. I would not expect that to go to the coolant sensor though - as I said, I don't have info for anything other than a 2008 STi, so it is possible they've changed things.

lee1981

Good point I will check the wire diagram for injectors and see where they go too.

salsa-king

the 330s is still the 2008 Hatch car, .... a load of cars in compound.. not sold, till 2009/10 etc still the base 2007/8 make year

TimH

iTrader: (11)

That's what I thought, but couldn't be 100% sure, hence the note of caution.

So, absolutely, there should not be +12V at the temperature sensor.

Also odd that the wire colours are different to the "book" - is it possible that this car has had work done to it or a replacement engine? What's the history of it?

lee1981

It looks completely standard, it has had an engine at 15k at the dealers, all wiring looks like standard connectors etc. it does look like to me it has had engine work done recently, the sealant on the sump looks new and you can see where bolts and clips have been undone etc, but I have no idea who has done it or where.

lee1981

Ok, a bit of an update!!! The car has been at the Subaru main dealer for nearly 2 weeks!! they originally told me it was a wiring fault and they could repair it, it now turns out they can not find any wiring faults! They say they have checked everything they can and that they suspect it is the ECU that is faulty.
There seems to be a fault when you un bolt the ECU from its bracket and move it when the ignition is turned on the fan actually goes off and the lights on the dash start flickering on and off and you can hear all the relays clicking behind the dash etc.
Now they are telling me it is the ECU and I need a new one or to get this one checked out, but I also believe there is a chance that it could be the wiring harness going into the ECU because surely if there was a bad connection it would show up when moving the ECU?? I have researched 330s ECU faults and seeing that these are a denso ECU no one has seemed to have any faults so it seems unlikely that mine is the only one....??

ditchmyster

iTrader: (7)

They could just take an ecu out of another car and try it in your car and see if it cures the fault.

Just a thought that might save you a few quid.

lee1981

Yes I did ask them that but they said they did not have one they could use, if anyone on here knows where I could get one to try that would be really handy..?

lee1981

Can anyone recommend anywhere that tests ECUs??

salsa-king

ask here....

https://www.scoobynet.com/763923-08-...elves-398.html

lee1981

Well....... bit of an update, after speaking to lots of people and coming to the conclusion that it would be very unlikely that the ECU would be faulty, I took it back to the main dealer and told them that it had been tested and was all ok and that it must be a wiring fault!!



So.... 2 days later I get a phone call saying that the fault is now cured and it was a wiring fault!!!!



I went to the dealer today to pick the car up, they charged me 2 hours labour so could not argue with that! I asked if I could speak to the technician which they allowed me to do and basically it turns out that when he plugged the ECU back in the fault disappeared!! so obviously it was a connection fault.



The car now starts straight up and fan works as it should etc, but.... it has a misfire on number 1 cylinder!!! so the engine light comes on and the car is really sluggish, the dealer basically said they was not sure what it was and I would have to pay for coils and plugs etc to test first so I decided I am going to try and investigate myself....!



So guys any ideas what this misfire could be?? I took the plugs out before when I had the compression test done (which all was ok) and they all looked ok??