Technical Cinquecento 899cc Misfire

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Technical Cinquecento 899cc Misfire


New member
Jan 20, 2006
Hi Hope someone can help me,

My partner has a Cinquecento sporting which she loves N reg 55,000 miles .:)

However it recently started misfiring when it has always been a good runner and first time starter. I whipped the plugs out and they were very carboned up as if running rich. She had also mentioned a strong smell of petrol.
Cleaned plugs but no great difference getting very black again though after only a few miles.:confused:

In the end changed plugs and leads and all ran well although I noticed plugs were getting choked up again very quickly.

After about a week of running she mentioned a return of a slight misfire and lack of engine power intemittently similar though not as bad as the original problem.:(

I think at first it may have been running on 3 cylinders due to a faulty HT lead I guess this is where the missing and smell of petrol was coming from however since I replaced those there is no smell of petrol but just the return of intermittent missing and slight lack of power occasionally.

The car is not using water and there is no suggestion of Creaming up in the Oil filler cap so I think the Head Gasket is ok.
I should point out the last time I worked on a car proper was way before all this fancy new stuff, points condenser and plugs was my thing!!!!

I think the car maybe running rich causing the plugs to choke up. I have seen ref on the forum to the Lambda sensor and MAP sensor controling mixture (I think) !!:confused:

1)Where are these sensors and are there any test that can be done to check them for operation ?
2) Any other ideas as to the possible cause?

All suggestions much appreciated.

Thanks Adrian
OK then its not sporting!

It must have had the (s) added to the badge and alloys put on it then.

Dont really know much about the different model nuances.

If we say its an 899cc OHV unless there were any other 899cc models does this help you ?


The ECU wqarning light isnt on is it? Thats the red light nearest the Left hand side of the dash that looks like a spray.
The MAP sensor sits on the inner wing on the passenger side. It is a flattish roundish thingy with a thin vacuum pipe going in one side and an electrical plug on the other.

It senses the vacuum and adjusts the timing as neccessary. The thin pipe can become clogged or split, either condition not good for acceleration.

The lambda is a known issue too, although it ususally throws the management light on.

Have a wee look at the crank sensor. Sits just above the crank pulley and provides the

Throttle position sensor would be next up to check. This is on the throttle body and there is not a lot to do to check it, but make sure the plug is in properly.


Fixed Cinquecento 899cc Misfire

:) Problem sorted, I hope.

Drove it myself yesterda and was was reported as a misfire was more a case of lack of power as if running on 3 cylinders.

Thanks to all of your help especially RALLYCINQ(y) you were spot on with the pipe from the MAP sensor. IT WAS SPLIT.(n)

Temporarily fixed with some tape nad now runs a treat:D :D :D

A BIG THANKS again to everyone for your help.