Technical Definitive Answer for fitting ECU Mk1

[PhilShef]

Hi all

Desperately looking for the definitive guide to fitting a new ECU to a MK1 1.2 petrol punto. A long unhappy tale. The car isnt mine but a friends. She bought it without red key and then went and lost the only remaining key. She was surprised to find the car would no longer run. I consulted this forum and found the best solution was to get a scrap ECU and lock set. This I did.
Fitted the ECU but found the injector warning light came on and the engine would not start. I noticed the fuel pump didnt whirr on turning the key so thought maybe it was a wrong ECU. Went back and got another ECU with key and locks. Fitted this. Fuel pump now whirrs but the injector light stays on and car does not start. So... what is the problem?

Yes I disconnected the battery overnight and this did not help.
The ignition aerial ring is fitted and the key does have the chip in it.
The answers on here contain a lot of varied information and it isnt clear.
I did notice that one guy was selling and ECU with locks and keys but also another box that connects to the ignition aerial ring. I havent got one of them.. just the aerial ring with lead. Is this the problem?

Can someone just detail the procedure for fitting a replacement ECU and lock set - correctly. Perhaps somebody who has done it.
Not the mechanical part.. just the flaming key and immobiliser bit!!

Thanks
Desperate, Sheffield
The ECU is IAW 16F.E3 46545152 61602.106.02
And the car is 1999 1.2L petrol

 

[thefallenangel]

Can't you bypass the little bit at all or find a scrappy with one to change?

 

[T14086]

you need the code box from the same car you got ecu/locks from...theres hundreds of posts on this, how could you miss it!

 

[fingers99]

If this is a Mk1 car, then it's SPI (single point injection) and all the coding is done by the transducer ring and antenae.

The easy way to do it is to buy an uncoded ECU chip (PM gazzaman2k) which will render the immobiliser circuit useless.

The next easiest way (all keys lost) is a new key/lock set and ECU (and ignition transducer ring assembly -- the ring must match the ECU).

But an ECU light -- I'm assuming the engine turns over -- tells you absolutely nada about the code system.

 

[d3xt0r]

The next easiest way (all keys lost) is a new key/lock set and ECU (and ignition transducer ring assembly -- the ring must match the ECU)

You dont need to replace the ring as the ring send the signal to the code box witch either accepts it or denies it.

I replaced mine last year, ECU, Code Box and Ignition Barrel, but not he ring.

d3xt0r

 

[d3xt0r]

I've just made a guide for replacing ECU and Code Box, but not replacing locks as i havent had to replace my locks as of yet.

 

[PhilShef]

Quite easily the forum is a bit like Wikipedia.. quite a lot of misinformed or plain wrong information. Hard to find THE authoritative answer.

 

[fingers99]

Of course. But to repeat myself:

But an ECU light -- I'm assuming the engine turns over -- tells you absolutely nada about the code system.

I think your last step -- I'm assuming the engine turns over -- sorted out the code issue. You now have another one to do more directly with the ECU.

 

[PhilShef]

Of course. But to repeat myself:

But an ECU light -- I'm assuming the engine turns over -- tells you absolutely nada about the code system.

I think your last step -- I'm assuming the engine turns over -- sorted out the code issue. You now have another one to do more directly with the ECU.

Well she hasnt got a handbook I dont know what the lights mean.
I have never seen a keycode light? I dont even know if her model has one.
I am guessing the bulb is gone?? The engine does turn over.. but will not start. I am assuming that a mismatched key would turn over the engine but not start it.. just like this.

I never got the code box matched with the new ECU so on the basis of your info I am assuming the mismatched code box sent an error to the new ECU and so.. it wont start. Working without the handbook or information is very frustrating and yes... I am pretty well sick of the whole deal.
I dont think there is a fault with the car in any other way. It was fine till she lost the key. Re-fitting the original ECU but keeping the new barrel and keys just does the same thing... car no start... still no key code light.. but then... that could just be a bulb?

Based on all the available advice and in the absence of the original keys... I am thinking getting the ECU re-written as free running and fit it back on.

 

[T14086]

Quite easily the forum is a bit like Wikipedia.. quite a lot of misinformed or plain wrong information. Hard to find THE authoritative answer.

take it to a garage and pay for the answer then!

 

[fingers99]

Based on all the available advice and in the absence of the original keys... I am thinking getting the ECU re-written as free running and fit it back on.

If this is an SPI car (one injector) it should have come with a blue and red key. The easy way to overcome the immob is to fit one of gazzaman2k's chips. Probably a lot, lot, cheaper than sending the ECU off.

 

[PhilShef]

take it to a garage and pay for the answer then!

Yes helpful... the other great use of the internet the opportunity for low rent amateur stand-up.

Actually in my experience that approach wouldnt give a definitive answer either. There are garages and garages.

But thanks to the helpful folk who responded.