General hesitating?

[mattyguk1]

hi all, my daughters sei 1.1 sporting hesitates when pulling away? the power/revs drops when you try to pull off for a second then pick up again. so far ive changed fuel filter,plugs,leads and air filter but no change! could it be the pump? any suggestions appreciated....

 

[cc1]

Which yearis it< MPI/SPI?

 

[mattyguk1]

hi,1999 spi

 

[rallycinq]

Highly unlikely to be pump, its running at a constant pressure all the time.

Have you cleaned out the Map tubes/made sure they are intact?

Cheers

D

 

[mattyguk1]

thanks for reply, where exactly are the map tubes? and ill give them a clean and check

 

[fingers99]

Look for a long black pipe running from the centre of the engine out to a bracket mounted on top of the ECU on the passenger side front wing. If the tubes are intact and clear, you might try another MAP sensor (at the far end of the pipe, on the bracket).

 

[mattyguk1]

ive found a pipe coming from centre of engine over to passenger side with an inline filter/vaccum in marked carb one way distributor the other way? is this the correct pipe? well this pipe was cracked and split at wing end so i thought id found problem, renewed pipe and now i have another problem..... the car barely runs! im guessing sombody has adjusted something in the past to compensate the split pipe? any ideas?

 

[fingers99]

My guess is that the MAP sensor has gone down. Not overly expensive -- you might pick one up for a fiver from a scrappy -- and very easy DIY job.

 

[mattyguk1]

cheers,is there a picture of a MAP sensor anywhere i could view?

 

[fingers99]

Just go on eBay and do a search for Fiat Cinquecento Map Sensor and lots of pics will turn up. The one for the MPI models is 4 pin, you want the 3 pin type, hence the Cinquecento search.

Bound to be pics in the Seicento Tech Manual (free from the Dowmnlods section) -- green arrow at top of page.

 

[mattyguk1]

cheers, out of interest why would the car run so much worse after i stop the leaky pipe?

 

[fingers99]

My guess is 'cos the MAP is fubar -- disconnecting it will have much the same effect as running with a big hole in the pipe.

 

[rallycinq]

Also check that the vac pipes are the right way round on the TB.

Cheers

D

 

[fingers99]

Also check that the vac pipes are the right way round on the TB.

Cheers

D

Yup. There's a diagram I put in the guides or faqs.

 

[mattyguk1]

thanks chaps, fingers on your diagram in guides which are the vaccum pipes to check are right way around?

 

[mattyguk1]

will any of the three pin sei/cinq sensors be ok as part numbers on ebay listings dont match mine?

 

[fingers99]

Should be fine. There are actually 2 lots of FIAT part numbers! For best results, try eurocarcare (Fluffy the Impaler) eBay shop "It's Cento Time".

 

[rallycinq]

thanks chaps, fingers on your diagram in guides which are the vaccum pipes to check are right way around?

The ones for the map and the inlet flap.

Cheers

D

 

[mattyguk1]

hi all, new MAP sensor fitted but no change! anymore advice would be great. to recap, the car was hesitating when pulling away ,checked pipes and found the MAP sensor pipe was holed so i renewed it which has made the car struggle to tick over. in fact it runs better with pipe disconnected! could a previous owner have adjusted something to make the car run better if they hadnt noticed the holed pipe maybe?

 

[levemircento]

pull the long plug out of your ecu, then plug it back in after 5 mins, this will reset the ecu and the engine might run better

check the small vacuum tubes [like the map sensor tube] that are on the inlet and back of spi unit, any leaks in these will result in poor running