306 ECU or any HDi 90 ECU

[stevomcguffster]

After months of trying to fix my 306 HDi D Turbo I now think that the ECU is at fault. I've replaced lift pump, high pressure pump, fuel pressure sensor, etc. This was done because I had a code telling me that my fuel pressure was to blame for not running. However I now can no longer get any response from the ECU when I have the computer hooked up to the car. Could I have damaged the ECU by trying to jump start the car with more powerfull batteries, still 12v though...

If I have to buy an ECU can I just get any one that came out of any HDI 90 powered car or do I have to seek for one specific to my model? Would it seriously affect the car's performance if I took one from say a 406 HDi 90?

Any help would be very much appreciated. I like to fix things with hammers and man sized tools so these sort of things tend to frustrate me...

Thanks Steven

[spider]

I would guess you need one from another 306 preferably the same year.

At least they are not plexed which reduces the complications a bit too.

I don't think you'd damage it via jump starting unless you had the battery the wrong way around etc, although I'd guess it has a protection diode anyway.

I'll take a look later but I suspect the part numbers for say a 406 will be different. At a minimum you'd want one from a non-plexed donor.

Bear in mind the donor ECU will need a quick diag session to be told about the keys as well unless you get the transponder chip from the donor too.

[stevomcguffster]

Thanks mate. What do you mean by non-plexed? Also is the transponder unit also known as a bsi unit? Is it located next to the ECU in the engine bay? I'm assuming the aerial around the ignition barrel is just a receiver and will read a different key?
Thanks again, hopefully get the parts ASAP and get this running.
Steven.

[Peter.N.]

If it still won't start when you get it sorted an internally leaking injector can cause low rail pressure.

Peter

[spider]

Peter raises a good point. I'd assume that low fuel pressure (I know it won't open the injectors if its too low) would be recorded / listed when running a diag though.

Regarding your questions:

306's are not mulitplexed, the later wiring system fitted approx 2000 model year onwards (but not 306's or 106's) I was just saying a donor ECU from say a 406 at a minimum must not be plexed although I'd want a 306 one to be sure. I've not had chance to check the wiring yet to see if they are the same (part numbers that is)

Transponder is not known as the BSI no, you do not have a BSI

The ring around the ignition switch is the tranponder aerial, this reads the chip in the key and sends the information to the ECU to decide if its the correct key code or not. A planet will be able to code new keys although if you get the key (or the chip at a minimum) from the car the donor ECU is coming from it should be OK.

[spider]

OK had a look.

For a 306 with a DW10 unit the only ECU (Injection Calculator) is 1929TF

There was not one listed for a Expert / Partner/ 806 as my the data I looked as is too old.

For a 406, there's two listed, I suspect one is FAP and the other is not or one is plexed and the other is not difficult to say really. I don't think its a 90 vs 110 thing with the ECU.

1929SE 406 DW10TD Depol CEE 95
1929SC 406 DW10ATED

In other words, it appears as I originally thought, you've got to have a 306 one unless you want to risk getting one that either will not actually plug in or will not work. I realise you're not having a new one , but it was worth checking part numbers in case the same one was used in another vehicle if nothing else it would of widened the donor scope for you.

[stevomcguffster]

Thanks guys, seems this is a bit trickier than I first thought. The only ECU I can find with the exact same numbers as mine is a remanufactured decoded plug and play at about £150 whereas other 2nd hand ECUs are under £50 but will still need coding to the car. I'm thinking for ease of use etc just to opt for the plug n play version unless anyone knows reason not to. I am aware that my immobiliser would not work with this ECU.
Steven

[spider]

A used cheap one should work as I posted above however you *must* have the key from that car, or a minimum the transponder chip from that key. Then it should not need coding if you fit that chip into your existing key.