Technical seicento mpi immobiliser

[oldskoolmk1unoturbo]

was in my missus seicento earlier and whilst stopped at a junction the engine cut out and wouldnt re start, i checked for spark and there was none, the key code light which normally goes out when you start the car stayed lit up on the dash,

we went and got the spare key but it was no different

whilst on the phone to the rac 20 minutes after it cut out the engine restarted the key code light is now no longer lit,

this is the 3rd time the car has done this and its doing my head in, the ecu light is always either lit up or flashing,

we had the fault codes read and it came back as coil pack miss firing, coilpacks have been swapped with 2 different units and still exactly the same. the codes were cleared but have re appeared the same.

i dont want to drive the car through fear of it cutting out and leaving me stuck somewhere.

help!

p.s the seicento is a 2003 MPI with punto 75 engine, running standard 1.1 ecu

 

[fingers99]

I'd think both could be faulty wiring. Check/replace those earths.

 

[oldskoolmk1unoturbo]

which earths where?

could it be a faulty ecu?

 

[fingers99]

Start with the main ones -- the batt -ive to os wing and gearbox to ns wing. Don't just look at them, take them off, scrape them, vaseline and tighten up. You could run another to the coil pack mount. There's another earth point around the A post area in the passenger footwell.

No guarantees, but a cheap way to start.

I have a lot of faith in the late Sei MPI ECUs, but some silicon grease on the big main connector can't do any harm.

 

[oldskoolmk1unoturbo]

i bought new battery and gearbox earth wires and fitted them, ecu light still flashs though :-(

 

[fingers99]

Ah well, as long as it doesn't cut out!

Guessing really -- does a code read show anyything? Some of the better readers can record events live.

I'm wondering if the changes are outside the perameters of the existing ECU (you'd expect fuelling and advance to be pretty different). Maybe the lambda is picking up something unexpected?

I'd suspect it may really need a remap, but it could be a transient issue with the cam sensor or knock sensor.