Technical 2001 Punto 1.2 8v running on two cylinders (faulty ecu)

[Halse108]

Hello,
Thanks in advance for any help. My newly bought punto recently cut out on two cylinders. With the help of a mate I got it diagnosed back to the ecu. The ecu is not providing the pulsed earth signal to time the spark. I saw that there is a previous post with the exact same problem. I read up on that and think the fix for the problem is to replace the ecu with an ecu with immo off or to get a kit with ecu, immo and ignition lock w key. My question is if it is correct that an ecu with immo off can be directly swapped in and that I then could use my original ignition lock and key? Also if I buy the kit is it plug and play or will there still be coding required? Lastly can I use other ECUs that look similar but w a different serial number? The serial number on my ecu is IAW 59F M3.
Thanks
Halse

 

[the green vanper]

Hello,

Looking at a different thread lately for a 1st gen panda ECU I've found this over the internet:

Naprawa sterownika silnika Fiat

Naprawa sterownika silnika Fiat - Elektro-BIP - Serwis elektroniki samochodowej

elektrobip.pl

They say that they can repair the 1.2 l engines ECUs under some conditions. I think that there should be other companies doing such things, so perhaps it's worth checking and eventually repairing.

I think that replacing with an ECU with a different number would not be that easy, but I can be mistaken.

The village of Reda is just on the other side of the big lake

 

[Halse108]

Great! Thank you for the link, will contact them for pricing.

 

[the green vanper]

They have got not the best opinions on google, so I'd rather suggest finding another one, it was just an example that such things can be repaired. And I am 100% sure that there should be more companies which conduct such repairs, perhaps even locally in Sweden.

 

[judderbar]

On digital-kaos.co.uk posters are saying that ECU is repairable for that fault if the hardware is greater than 100. Eg HW303. But if less than 101 the ECU has to be replaced. There is a method to get the plastic top off. I think the repair involves replacing the wires that go from the terminals to the circuit board. The wires melt when the coil gets shorted.

 

[judderbar]

Interesting reading the comments on this one to get tips on soldering to Aluminium! One problem with this kind of repair using solder is if the wires are prone to getting hot the solder is going to melt or degrade eventually.

 

[the green vanper]

Different solders have different melting temperature. The more resistant ones are harder to sold, but could be a solution in such conditions.

 

[varesecrazy]

The ECU driver board was quite a common failure 10 /15 Years ago, when these cars were in daily use

Lack of engine servicing..
Spark gap increasing made the Coils work harder, extra load damaged the board

 

[Halse108]

On digital-kaos.co.uk posters are saying that ECU is repairable for that fault if the hardware is greater than 100. Eg HW303. But if less than 101 the ECU has to be replaced. There is a method to get the plastic top off. I think the repair involves replacing the wires that go from the terminals to the circuit board. The wires melt when the coil gets shorted.



View attachment 456178

Bad luck for me my ecu reads hw003. Digital kaos says on first version of the ecu the cpu needs to be replaced, therefore an unviable repair. Any advice on how to best proceed?

 

[judderbar]

I see on Ebay there is a virgin (plug and play) HW303 ECU available in Poland for 119e. But that seller is saying you need the exact part number. Can you find your part number on the Finnish car parts web site?

Injection Control unit to FIAT PUNTO (2000-2018) | 71736339 | MAGNETI MARELLI

Looking for a FIAT PUNTO (2000-2018) Injection Control unit? Get MAGNETI MARELLI OEM part "71736339" for model 2001. High quality, reliable, and available with quick delivery.

www.varaosahaku.fi

If you can find a cheap non virgin ECU with the same part number it can be made virgin if you can find somebody with the right software such as the company in Poland but with postage I doubt you save money.

 

[Halse108]

I see on Ebay there is a virgin (plug and play) HW303 ECU available in Poland for 119e. But that seller is saying you need the exact part number. Can you find your part number on the Finnish car parts web site?

Injection Control unit to FIAT PUNTO (2000-2018) | 71736339 | MAGNETI MARELLI

Looking for a FIAT PUNTO (2000-2018) Injection Control unit? Get MAGNETI MARELLI OEM part "71736339" for model 2001. High quality, reliable, and available with quick delivery.

www.varaosahaku.fi

If you can find a cheap non virgin ECU with the same part number it can be made virgin if you can find somebody with the right software such as the company in Poland but with postage I doubt you save money.

From what I can see my part number is 46808846. That does not match the numbers on the Finnish site.

 

[judderbar]

This virgin 46808846. is in Poland on ebay. https://www.ebay.co.uk/itm/225785120206?_skw=IAW59FM3+46808846+HW003&itmmeta=01JEH49BN8H30F4XZ5VW7VTSHQ&hash=item3491d785ce:g:0GEAAOSw5CphcCuX&itmprp=enc:AQAJAAAA0HoV3kP08IDx+KZ9MfhVJKlTbjd51hoJy8KU1uH3k0IAUeuAlzLs/HasOx49RidFePVf8t5CG+MeCwt0EEe2iXvJxV7T7Tim4ZYZg43tvgR1kJUKMsMl9H5IwX/3GmhrowsCJqKnd5ot3MLQmuUx7N6cyluWNWfS6CZRjhsdcykyayz9uAY/6vmR4jbYw50LnvheUAOSpw0hs3aWmfjm9MNy9XJzXJH20qITpxROzitItkf4L2c8WUC7pYVnqblmoT6ARPp1Lw8uYp22SuZpM4A=|tkp:Bk9SR_C6paT0ZA

 

[Halse108]

Thanks, ordered that one.

 

[Halse108]

This virgin 46808846. is in Poland on ebay. https://www.ebay.co.uk/itm/225785120206?_skw=IAW59FM3+46808846+HW003&itmmeta=01JEH49BN8H30F4XZ5VW7VTSHQ&hash=item3491d785ce:g:0GEAAOSw5CphcCuX&itmprp=enc:AQAJAAAA0HoV3kP08IDx+KZ9MfhVJKlTbjd51hoJy8KU1uH3k0IAUeuAlzLs/HasOx49RidFePVf8t5CG+MeCwt0EEe2iXvJxV7T7Tim4ZYZg43tvgR1kJUKMsMl9H5IwX/3GmhrowsCJqKnd5ot3MLQmuUx7N6cyluWNWfS6CZRjhsdcykyayz9uAY/6vmR4jbYw50LnvheUAOSpw0hs3aWmfjm9MNy9XJzXJH20qITpxROzitItkf4L2c8WUC7pYVnqblmoT6ARPp1Lw8uYp22SuZpM4A=|tkp:Bk9SR_C6paT0ZA

Just a bit concerned that the the underlying problem still persists and the virginized ecu will likely fail due to that. Thinking that, if possible, it might be a better long term fix to buy a hw303 with beefed up output wiring to deal with the abnormal load drawn by the ignition coil. B

 

[judderbar]

Just a bit concerned that the the underlying problem still persists and the virginized ecu will likely fail due to that. Thinking that, if possible, it might be a better long term fix to buy a hw303 with beefed up output wiring to deal with the abnormal load drawn by the ignition coil. B

Maybe you can use a power transistor to control the current to each coil and leave the ECU to just manage the 12V to 0V signals that controls each transistor?

 

[Halse108]

Maybe you can use a power transistor to control the current to each coil and leave the ECU to just manage the 12V to 0V signals that controls each transistor?

I like the idea. I did a quick search on the forum, but could not find any further posts about using a power transistor to control the current flow. Would you have a more specific idea of a particular power transistor that might work?

 

[Halse108]

Maybe you can use a power transistor to control the current to each coil and leave the ECU to just manage the 12V to 0V signals that controls each transistor?

A Google search lead me to a Reddit post where someone mentioned that one could use a 90s Subaru igniter. One such module is said to be capable of controlling four ignition coils.

 

[judderbar]

I like the idea. I did a quick search on the forum, but could not find any further posts about using a power transistor to control the current flow. Would you have a more specific idea of a particular power transistor that might work?

Unfortunately I am not qualified to give you specific information. Like you I was googling for information and noticed you can buy smart coils (compared to our dumb Punto coils) with the transistor built in but these were not cheap and the ones I looked at needed a 5volt trigger? whereas we need a grounding trigger. But you have got me interested in doing something on my own car (adding to my huge list of things to do). I have a spare cloned ECU (which was possible DIY for my 16V ECU), but with both ECU's I get a surprisingly weak yellow spark that is barely visible even in my garage. Maybe big fat bright blue sparks are old school? I am doing everything DIY so I dont know what is normal. I had a thread on the forum about the weak spark about 10 years ago but since the car works I just left it as it is.

 

[judderbar]

A Google search lead me to a Reddit post where someone mentioned that one could use a 90s Subaru igniter. One such module is said to be capable of controlling four ignition coils.

Interesting. But in case you dont know we only need two coils because the 1.2 Punto uses the wasted spark method with just two trigger wires.

 

[Halse108]

Unfortunately I am not qualified to give you specific information. Like you I was googling for information and noticed you can buy smart coils (compared to our dumb Punto coils) with the transistor built in but these were not cheap and the ones I looked at needed a 5volt trigger? whereas we need a grounding trigger. But you have got me interested in doing something on my own car (adding to my huge list of things to do). I have a spare cloned ECU (which was possible DIY for my 16V ECU), but with both ECU's I get a surprisingly weak yellow spark that is barely visible even in my garage. Maybe big fat bright blue sparks are old school? I am doing everything DIY so I dont know what is normal. I had a thread on the forum about the weak spark about 10 years ago but since the car works I just left it as it is.

Do you know if the upgraded hw303 ecu would work in a car with hw003 as original? Was thinking if it would work if one bought the kit with ecu, immobilizer and key.