Alfa Romeo Forum banner

147gta diy ecu repair

Tags
diy
73K views 200 replies 54 participants last post by  Hperformance 
#1 ·
Hi,

I am posting this because it might just help someone else from my findings and stop them from wasting large amounts of cash..

After my Alfa being laid up for the past two years and rarely moved I fitted a battery to it a few weeks ago to find the engine warning light flickering a relay clicking away and the throttle body jumping and immobiliser warning.

I unplugged the throttle body and found that the engine would now start but would not start with it plugged back in. So I stripped the throttle body to find no problems. I tried a smaller motor connected and that spun without crashing the ecu... hmm I thought,,

Flashing ecu on and off only when drawing current sounds like a power supply issue to me. So I got out my scope and checked the power at the connector when this was happening with no real disruption.

So I then removed the ecu cover and had a poke about and found the connections from the thottle motor to the ic that drove it and then checked the power rails with the scope at the nearest large yellow capacitor. All I could see on the scope were very large voltage dips and spikes each time the motor and relays were jumping. Suspecting the capacitor i grabbed a random leaded capacitor from my selection and held it across the existing cap. My friend turned the key and the car started with no fault....

SO, I VERY CAREFULLY removed some of the silicone gunge from around the capacitor and found as I did it the capacitor fell off!... So out came the soldering iron and I very carefully soldered it back in place..

The discrete components on the PCB are actually glued down as standard with expensive conductive glue....

Covered it in flowable silicone and sealed the lid back on.

Job done..

some photos >

http://i889.photobucket.com/albums/ac93/pemtek/IMG-20130402-WA0001.jpg
http://i889.photobucket.com/albums/ac93/pemtek/20130402_200610.jpg
http://i889.photobucket.com/albums/ac93/pemtek/IMG-20130403-WA0000.jpg

Phil
 
See less See more
#2 · (Edited)
Good work Phil! Wonder if this could be a common cause of ECU failure? Would save a fair few people a lot of cash if so. If anyone with a broken one wants to send it to me I'll happily resolder it if it's the same issue.. Not that I have a GTA to test on any more - although I assume it would need virginalising before it would work on another car anyhow? :(
 
#10 ·
I think you are winning post of the year so far, well done!

I suppose not all ecu faults are the same (or maybe they are!) but excellent work tracking yours down. I'm sure ecu faults have been the death of some higher mileage GTA's too.

Could be worth a mention in the general area too, I suppose similar age 147/156/166/GT models have a similar ecu construction.
 
#11 ·
Nice.... great detective work! It's come 6 months too late for me and many others, but very useful intel for people going forwards. I think I have my broken one in the garage still, so will check to see if it's got a similar problem.. I suspect it will, as my symptoms were EXACTLY the same. I have 0 experience with electronics though, so it might take me a while :/
 
#13 ·
That'd be awesome Olly, thanks for the offer, I'll check the garage and hopefully it's still in there, although I don't hold out much hope (my family love to clear stuff out & bin it). I could see the BM too then :)
 
#18 ·
Nice work Phil. So is this the ECU fault everyone has been getting I wonder :think:
 
#19 ·
Top work, I love how people just like to get stuck in and try things.

You could have potentially saved some cars!
 
#22 ·
A great combo. Nice work.
 
#24 ·
bottom right of the PCB see if that yellow component is loose.

It is easiest to test these things with them connected to the car using an oscilloscope sadly.

Be careful all the hair like wires are gold and are extremely delicate, disturb one and its in the bin..


I just use the Elise for trackdays, however I am just about to upgrade it to a 2.0 16v pd tdi engine with a dsg paddle shift gearbox. I would like to enter an endurance type race because nothing overheats and it is very fuel efficient compared to petrol cars.

Phil
 
#25 ·
bottom right of the PCB see if that yellow component is loose.

It is easiest to test these things with them connected to the car using an oscilloscope sadly.
Unfortunately it is firm. Actually all those big parts sit firm. Without the knowledge and tools you have it is in the bin for me i suppose. There is nothing looking wrong on it.
 
#27 ·
It's a small world.. when I read about your Elise I thought - I bet I know someone who you know who I always talk cars with when I see him.. I had a meeting with him today (we work for the same company). I said "Do you know somewone with a diesel Elise?" - he pulled out his phone and showed me a video of you driving on a track taken from his Exige :)
 
#29 ·
I had the same issue 6 months ago and sourced an ECU from autolusso which had been revirgined(gotta love the use of that word). All well so far - thank you Ned and the lads. Took apart my original ECU today and started prodding the components and they all seemed fine. However a slightly harder push of the same component as featured in the picture at the start of this thread resulted in it coming loose. I put much harder force(but still within reasonable limits) on the other components and nothing budged. I need to solder mine in and test but I reckon I have a spare ECU for when the same problem happens again in ten years time - in this for the long term. Will post when finished
 

Attachments

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top