Technical Won't start after ecu change

[GRAHAM L]

Hello, just joined, impressive level of knowledge here so I am hoping for some advice.
I have a 55 punto 1.2 8v lost power on 2 cylinders, changed coil pack, same problem 2 weeks later although coil pack is fine. Changed HT leads and plugs no difference
Assumed ECU coil driver fail after reading forum so replaced ECU with 2nd hand one but now the car will not start. Turns over but that's it. Any ideas?

 

[Scudmonkey]

Is the Padlock symbol light illuminated on instrument panel ?
unless you bought virgin engine ecu car wont start with another ecu even if numbers match cuz its all coded to the car.
This means Immobilizer will stop it from running

 

[Ziggy122]

A scrapyard ecu needs the other main body electrics and keys and locks and fuel cap and airbag barrell etc to match

Cant mix and match parts

Ziggy

 

[GRAHAM L]

Yes that light is on, so I guess there is little point to 2nd hand ecu s then, I was just making sure the numbers were right didn't know about the immobilized issue. Don't suppose there is a way round it?

 

[Scudmonkey]

2 ways round it..1st is get an uncoded (ie virgin ECU)
2nd is as Ziggy said, change all the ecu, door locks, igniton barrel ,keys and main body electrics etc.
Have a search through the threads as there are people on the forum who have used Virgin ECU replacements

 

[AndyRKett]

The only way round it would be to get all the other parts as stated above from the same car your replacement ECU came from.

Or by another but brand new Engine ECU which will code itself on first use to your car.

 

[g8rpi]

Yes that light is on, so I guess there is little point to 2nd hand ecu s then, I was just making sure the numbers were right didn't know about the immobilized issue. Don't suppose there is a way round it?

Where are you located? I might be able to copy the code from the old ECU to the new one. I've not done it before but if you are near Cambridge I'd like to have a look.


Robert G8RPI

 

[judderbar]

Hello, just joined, impressive level of knowledge here so I am hoping for some advice.
I have a 55 punto 1.2 8v lost power on 2 cylinders, changed coil pack, same problem 2 weeks later although coil pack is fine. Changed HT leads and plugs no difference
Assumed ECU coil driver fail after reading forum so replaced ECU with 2nd hand one but now the car will not start. Turns over but that's it. Any ideas?

So it worked for two weeks after the coil change? I suppose you have two coil packs? Could be the new coil was not a high quality one and quickly failed. This fault involving cheap coils has been mentioned very often on this forum - probably got over looked this time.



1. by removing the plug leads identify which coil pack is 'not working'


2. Swap the coil packs being careful to ensure you dont change the wiring other than the coil pack positions


3. Repeat 1. to see which coil pack is 'not working'.


4. if the fault moves to the other cylinders then the ECU is not faulty.



People who have done this before can advise better than me.

 

[AndyRKett]

Where are you located? I might be able to copy the code from the old ECU to the new one. I've not done it before but if you are near Cambridge I'd like to have a look.


Robert G8RPI

I'm sure I have read in the past that people have gotten these working by transferring the chip that carries the code, from the broken ecu to the new one.

 

[g8rpi]

That was my thought, or even copy the code from the old one if the chip is FLASH. I have the skills and equipment to do either. The linitaion would be the chips used and physical construction of the ECU.


Robert.

 

[GRAHAM L]

I'm in Dorset so couldn't get much further away from Cambridge, thanks for the offer

 

[GRAHAM L]

So it worked for two weeks after the coil change? I suppose you have two coil packs? Could be the new coil was not a high quality one and quickly failed. This fault involving cheap coils has been mentioned very often on this forum - probably got over looked this time.



1. by removing the plug leads identify which coil pack is 'not working'


2. Swap the coil packs being careful to ensure you dont change the wiring other than the coil pack positions


3. Repeat 1. to see which coil pack is 'not working'.


4. if the fault moves to the other cylinders then the ECU is not faulty.



People who have done this before can advise better than me.

Got Lucas coil packs and yes swapped them round and fault stays on same cylinders

 

[s and b]

waste of time opening these ecus up to repair them as they break as you open them
thats assuming you dont chop a finger off in the process
once opened you would note they have wires to the coil drivers thinner than a human hair
they are put together on mars by the little people with little fingers

to the original poster..................
if the ecu numbers on the replacement ecu are the same ie yours is on a 55 plate so may well end m5 then it is feasible to have these virginized for about £35 i looked into buying the gear but balked at the cost and as proved would have been money wasted
i have the details at home if you need the link
ive looked for my link where its a one minute job to check the ecu for workability before you send it off because some so called repairers want to charge robbin money to do the simple check but unfortunately i cant get my link to open as im now on windows 10 and after trying for a couple of hours last night i admitted defeat
basically you were looking for a reading from the two output pins to earth and comparing them ie they should have basically the same readings if it was well out it meant the driver circuit was not working and was open circuit

 

[judderbar]

there are chip tuning forums where you can get the ecu virginised for no charge if you provide the .rar file to enable the hex to be changed. I am a member of mhhAuto.com. Costs 10 dollars to be a member and then download files.



I know almost nothing but did manage to clone my ECU as a back up.


On my 16V ECU there is more or less alien technology in the form of a 'hybrid' board. (hybrid style here: http://geneticmotorsport.com/ckfinder/userfiles/images/a06671af197b54df.jpg) The electronics are very easy to access via an easily removable plastic cover but the components are microscopic and covered in gel. I think I am right in saying the flash is part of the microprocessor rather than a separate flash chip. I do not believe you could heat gun that kind of tiny chip off the board and hope to replace it. The gold wires are bonded. Sometimes the ecu fails because the bonded wires break at the connection and are repairable if you can rebond them. Solder is possible for that but i think hit and miss. On my ECU i was fortunate the VW guys had made their own chip tuning software to download the 'flash' file. All i had to do was put a ground wire in the ECU plug on the car to enable 'boot mode' and do the work via the OBD2 plug inside the car to clone my spare ECU. I had the ME73H4001 type of ECU where those 7.3 ECU's were common in the vws and audis

 

[AndyRKett]

waste of time opening these ecus up to repair them as they break as you open them
thats assuming you dont chop a finger off in the process
once opened you would note they have wires to the coil drivers thinner than a human hair
they are put together on mars by the little people with little fingers

The electronics are very easy to access via an easily removable plastic cover but the components are microscopic and covered in gel. I think I am right in saying the flash is part of the microprocessor rather than a separate flash chip. I do not believe you could heat gun that kind of tiny chip off the board and hope to replace it.

As much as I have disagreed with with g8rpi in the past on this forum, I don’t doubt for one second that this would be a fairly straightforward job, not only which what he does for a living but also the type of equipment he will have access to because of what he does for a living.

 

[g8rpi]

As much as I have disagreed with with @g8rpi in the past on this forum, I don’t doubt for one second that this would be a fairly straightforward job, not only which what he does for a living but also the type of equipment he will have access to because of what he does for a living.

Thank you for the vote of confidence. I did say the construction of the ECU could be an issue. This sounds like Chip on Board with silicone gel encapsulation. One of the hardest to do, but opaque epoxy or silicone rubber are almost impossible. I have repaired units with this type (CoB/Gel) of construction in the past but it is not easy and probably not worth trying if you can get a used ECU virginised elsewhere. It's not worth buying (or reverse engineering) the software to do this by external means for a one-off.


Robert G8RPI.

 

[s and b]

Thank you for the vote of confidence. I did say the construction of the ECU could be an issue. This sounds like Chip on Board with silicone gel encapsulation. One of the hardest to do, but opaque epoxy or silicone rubber are almost impossible. I have repaired units with this type (CoB/Gel) of construction in the past but it is not easy and probably not worth trying if you can get a used ECU virginised elsewhere. It's not worth buying (or reverse engineering) the software to do this by external means for a one-off.


Robert G8RPI.

i posted up a picture of one i opened up a few years and yes it has the gel in,these guys who claim to repair often only virginize good ones they used to buy in as core,this was why whenever i went to a decent yard all the ecus had gone
im not saying it cant be done im saying that these are built on a line where humans just make the tea
no offence

 

[DaveMcT]

I'm sure I have read in the past that people have gotten these working by transferring the chip that carries the code, from the broken ecu to the new one.

The chip in the ignitions key(s), ECU and instrument cluster are all coded together. A used ECU its useless without the other two components.

You do not need to change the immobiliser antenna or the ignition lock or the door locks as these have no coded components.

"All" you do is fit the set of ECU, cluster and ignition key chip. You can swap the chip from the "new" key to your old ignition key. You do not need to swap all the mechanical locks.

However, take care to save your old immobiliser chip and other kit as you might need it.

 

[judderbar]

The chip in the ignitions key(s), ECU and instrument cluster are all coded together. A used ECU its useless without the other two components.

Not so.



1. A factory new (virgin) ECU will automatically boot up and transfer the code from the body computer.


2. A used ECU can be made to appear as a new one by changing the hex code in the ECU - virginising. That ECU will then work for any car needing that type of ECU.



3. You can copy the hex code from a defective unit in the car to a used one that is good for that car only - cloning.

 

[GRAHAM L]

Ok so I bought a virgin ecu from eBay, same problem with immobilizer not letting car start, eBay seller sent me another and that one does exactly the same thing. Either got a seller who is happy to keep sending out ones that aren't coded properly or am I doing something wrong, I am following the instructions, disconnecting battery etc