my car a cinquecento sporting 1108cc spi on a p reg has been diagnosed with an ecu fault. does anyone have any ideas of were you can get one from plus if i get one from a scrap yard does it have to match up with the ignition key or can you get them de coded as i do not have the red key for my car.

any help will be very welcome.

An ECU fault generally does not mean that there is anything wrong with the ECU itself, rather that the ECU has picked up a wrong signal from one of the sensors on the engine. Cure that fault and you're done.

Maybe the best place to start is with you telling us what symptoms the engine is displaying: what does it do that it didn't use to?

well when you start the car up it runs fine for 5 seconds then its starts running rough and you can not drive it like this when you put the throttle down theres no power its just like there's not enough fuel getting there but some times you can rev it but then it wont. so we tried new plug leads new map sensor and it still runs rough after all this . eventualy it will stall when its ticking over it last about 4 mins then drops revs that low that it cuts out.

I had a simular problem i needed a whole new head very expensive!

so you dont think its the ecu you think it needs a new head

I don't think a new head will be necessary - let's not be too fatalistic about this

My first job would be to check the throttle body hoses for leaks, same for the map sensor pipe.

I would then check the TDC/crank sensor to see if that is dirty or out of tolerance.

Failing that, it could either need a new crank sensor a a new lambda.

Is it firing on all 4 cylinders?

eventualy it will stall when its ticking over it last about 4 mins then drops revs that low that it cuts out.

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This to me says lambda - the lambda sensor is ignored on start up/when the engine is cold.

Yes Shes Running On All 4 .will Try Lamba Tonight And Crank Sensor And Map Sensor Pipes And See If She Runs Any Better Will Let You Know Later Tonight. Do You Think It Is Likely To Be Ecu.

I reckon a broken ECU is less likely than a FUBAR'd sensor. I can't remember the last time someone on here had to change a Cinq ECU due to damage.

It sounds like the ignition coils should be OK then if it still runs on all 4 cylinders.

Lambda would be my first port of call if it only does it hot.

Don't just replace stuff. Get a meter and check the readings for each sensor against what they should be. If a sensor is sending duff information to the ECU, then it will do the wrong calculation and send the wrong amount of fuel, or the wrong ignition timing.

Cheers

D

this is the list of parts we,v tried so far

lamber sensor
coil packs x2
throttle body with all components
map sensor
plugs and plug leads
we changed crank pulley because it had corrosion

the car is running a tiny bit better it will just tick over without cutting out now but is still running a bit slow.
as for driving it will rev up with no load but as soon as you lift the clutch and start to put it under load it dies and kangaroos.

when its ticking over and you blip the throttle the fuel gauge needle moves down 4mm and then goes back up to normal.

another thing we found out tonight befor we got the car it failed the mot on hazzard lights not working and some bodging bas*ard has wired it up to the radio live wire can that have an effect if its dodgy wiring

Check the engine earths.

Cheers

D

Hi When I Changed The Lamba Sensor The Old One Was Bent And Was Broken Inside (it Rattled When Shaken) And It Was A Universal Sensor With The Wires That Have Been Connected Together But 1 Wire Was Broken Could This Fry An Ecu If The Sensor Had Shorted Out.

Ps. The Car Had Been In A Bump And Been Bodged By The Last Owner.

ECU's are designed to take electrical abuse, so probably not.

Is the injection system warning light coming on when the problems show up (red light, looks like a spark plug with spray coming off it)? If so, then the ECU will be logging the fault. The fault code can be read out, and the problem part identified.

You say it feels fuel related, have you changed the fuel filter? They're often overlooked in service. Its under the car, near the handbrake lever.