Technical Seicento won't rev past 3000rpm!

[davesei]

Hi Guys,

I haven't been here in a long time (I use to have a Seicento Abarth in my younger days and was here a lot back then!).... I'm hoping one of you guys could help me out in diagnosing a problem.

My wife has a 2003 Fiat Seicento Active. It's a great little car but has started to give us a real problem. On a recent trip out the 'check engine' light came on going up a hill and then the car wouldn't rev past 3000rpm, and has refused to rev past 3000 ever since!! I have an OBDII connector cable, so have hooked this up but the car doesn't give any error codes at all.

A friend suggested that the 'Lambda / Oxygen Sensor' may be faulty and that I should try disconnecting it. I've done this and it makes absolute no difference at all to the symptoms (I don't know whether this is good or bad!).

If anyone has any ideas of any tests I can perform to try to isolate the probelm it would be extremely greatly appreciated (if not I'll have to lend her my car, and I really don't want to do that ).

Thanks!
Dave.

 

[slugworth1987]

if the lights on its on get me home mode which restricts the engines rev limit down to 3000rpm look into why it came on if its an MPI engine which is OBDII if it isnt OBDII its a 3 pin diagnostic cable but it could be a range of things

if its the micro ECU system (early MPI) then could be worst case a dead ECU

things to check

O2, MAP, Crank/TDC sensor, Water temp sender

 

[cc1]

If the oxygen sensor has burned out then disconnecting it won't make a difference. Check resistance of cable pairs.
Pins 1/2 = 5K ohms.
pins 3/4 = 2.4 - 4.3 Ohms @ 20DEG/C.

 

[davesei]

Hi Guys - sorry I missed out some important info! The warning light came on when the problem initially started but went straight back off. Now when you rev up to 3000 the light comes on, the revs drop, the light goes out. if you keep your foot on the accelerator you basically go through that cycle over and over.

Thanks all!

 

[levemircento]

does it run on all 4 cylinders?

if not, it will be a coil pack and this will show up the light on the dash

if it does run on all 4, then I would go for a new lambda sensor

 

[rallycinq]

Leave the cable and reader on while it goes through that cycle and it will tell you why the light is coming on.

Cheers

D