Technically an uno turbo is FWD, so investigating ignition ECU

Alex(Tenerife)

Alex(Tenerife)

True Classic
So looking at cleaning up the loom and found some oddities/questions.

First it seems fiat used 2 different microplex ECUs for the 1301 uno turbo. I have the MED604C but have seen online MED603B. No idea of the differences between the 2 ECUs.

So I looked at my plug and comparing to the pin out and circuit diagram in the haynes manual and the fiat uno manual. They don't quite line up.
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My plug, you can see pins used are: 1, 2, 3, 4, 7, 8, 11, 12, 13, 14, 15, 16, 17, 20 and 23
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From the haynes manual (same in the service manual) 8 is not marked and neither is 23
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Here we have pin 8 - great that is the diagnostic socket.
23 is still not marked!
I gained a 22 which is marked as Turbocharger operation warning light (whatever that is)

So what is the light on pin 22?
What is pin 23 for?

What difference is there between the 2 ECUs listed?

This is mostly curiosity, and maybe a chance to add a fun new warning light!
 
Somewhere buried in my parts stash I have a Mk1 UT ECU, but not the harness that mates to it. If I ever find it again I can compare the part number with the ones you listed. If it's different from yours we could compare the pins on it. Otherwise I'm of no help with the wiring questions....I only have some UT parts and no real knowledge about them. But I'll be curious for the answers as well.
 
Alex, I happened to find the UT parts buried in my stash. The ECU I have is for a Mk1 and for the FI system. So I believe that is completely different from the one you are asking about? But mine has a Bosch part number: 0.280.000.336. However it wouldn't be of any help anyway because it has the standard connector array with no way to tell which pins are being used nor what they are for. And as I mentioned I don't have a harness. Sorry.
 
The bosch ECU is for fuel, the ECU I am asking about is for ignition. I believe fiat used 2 different microplex ignition systems for the mk1 plus the digiplex for the mk2. However after reading around I wonder if they also used the later mk1 microplex on some early mk2 cars.

I noticed today, if you look at the diagrams in my first post pin 12 changes colour depending on which page of the manual you are looking at!

Currently figuring out the loom so I can replace it with all new wires and connectors. Its very messy right now and doesn't feel reliable. Once I have sorted my diagram I will upload it here. Dr Jeff you should be able to use this plus the one one I already did for fuel to build a new loom for the stock ECUs, if you are interested.

Original reason for the post was to find out a) what is pin 23 for and b) what do the unused pins do? I will see where pin 23 goes tomorrow
 
Alex(Tenerife) said:
The bosch ECU is for fuel, the ECU I am asking about is for ignition.
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That's what I realized when I found the ECU I have. I could not remember which parts I had and was hoping there was a ignition control module as well, but unfortunately not.
 
Chris Obert said:
If I get stuck would you mind if I ask where a wire might go?
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No problem, happy to help and share anything I find. I am planning to get back to working on mine in the new year.

Last time I looked my diagnostic socket only had 1 wire of the 3 connected to anything.

More updates on this as I make progress.

I don't think I will find out what the extra pins are for, Chris if you have harness off a car any chance you can see where the diagnostic plug pins go? Manual says pin 8 and pin 22, but clearly there is no connector in pin 22! Not that I have anything to plug it into, just for completeness/if I do find something
 
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