Dimma Williams ECU issues advice needed

[aupshon]

I'm hoping someone here can point me in the right direction as I have been struggling for about 2 years now. I'll try and keep it brief.

I have a Dimma Williams, bought it a few years ago drove okay, wasn't great but drove well enough. Parked it away for a year or so (garaged) and then when I went back to start her she wouldn't idle, misfiring etc. Took it to a local Renault dealership. It sat there for about 5 months, they replaced a bunch of parts but went on about some sensor they couldn't get. Gave me a bill and returned it in the same shape but overfilled with oil.

I found a better rated dealership where they seemed to know about the williams, sent it off there. Similar story, sat for a couple of months. Apparently the ECU was corroded, they tried various things to duplicate the software and put it on another ECU, apparently it would not work and now they could not put the software back onto my original ECU because it has a 'prima power' chip. So another bill and now I have a non runner. The only difference was they tested all sensors and the health of the engine which gave positive results.

Are these cars really that hard to sort out with ECU issues or am I just being shafted non-stop? Can anyone assist or point me in the right direction.

[16v_paddy]

Sounds like you simply need a replacement ecu that has a chip carrier fitted to it.
Is the engine standard or has it been modified? If it's standard it's most likely the Prima chip is simply to raise the rev limiter so it's not really important and a normal working ecu will do the trick.

The part numbers on your ecu will also be important as it's possible to use the 1.8 16v ecu's on the Williams with a chip fitted so identifying what you've got will determine what you need

[aupshon]

Sounds like you simply need a replacement ecu that has a chip carrier fitted to it.
Is the engine standard or has it been modified? If it's standard it's most likely the Prima chip is simply to raise the rev limiter so it's not really important and a normal working ecu will do the trick.

The part numbers on your ecu will also be important as it's possible to use the 1.8 16v ecu's on the Williams with a chip fitted so identifying what you've got will determine what you need

Now that's a response that makes sense, thank you! The part number for my model is 7700864500. As far as I know it is standard, the garage mentioned that is had some fuel system modification but that's it. Would uploading photos of the ECU help? Do you know where I can get a new one and have the info transferred?

[16v_paddy]

The important numbers are on the left hand side

9927

The number ending in 107 is the main bit, that indicates that it's a Williams ecu. So if that's what yours is, if you get another Williams ecu that has a chip carrier fitted to it or get one and have a chip carrier fitted to it, you can swap the chip from yours into that one & it will do the trick. A standard ecu should also work fine with the engine being standard.

Finding a used one is going to be difficult but new is probably going to be impossible

[16v_paddy]

Seems like a bit of googling has turned up some surprising results that might be useful :shock:

https://www.actronics.co.uk/ecu/siemens-bendix-fenix-3/7700864500-hom7700864272-s101262107c
https://www.atcdrivetrain.co.uk/p/renault-clio-petrol-ecu/renault-clio-petrol-ecu-fenix-3-20.html
https://www.allcarpartsfast.co.uk/renault/renault-7700864500-computer-inj-cl/

[aupshon]

I just took a look in the garage and these numbers match, mine is the same ending in 107. What does the chip carrier look like, is this a piece that would be soldered onto a different board?

Thank you for those links, I believe i've spoken to actonics before and they don't seem to deal with corrosion but the others should hopefully be able to help. I'll have a hunt for a used ecu and hopefully something pops up. I assume my immobiliser won't cause more issues or should I just look at getting that removed?

[Wobba]

Yea, so the big chip on the board is the EPROM. With a carrier, that chip gets removed and a slottable carrier put in place so you can swap out whatever chip you want. But, it might not be the EPROM itself, it could be another blown part on the ECU. What parts did they change?

[Wobba]

9928

Pretty sure it is that chip. This is a 107. they can blow on other bits though so check for scorch marks underneath.

Or it is the bigger chip on the left...can't remember!