I have been having a problem my Seicento 1100 losing power when hot. It will also do it if allowed to just idle and as comes up to temperature it will stutter then stall.

Today I have exposed the top of the fuel pump and put an ammeter on the supply wire to measure the current. Initially with the engine running it will hover around 4.8a. As the engine gets hotter it starts getting lumpier. The current varies wildly from 3 to 4a until the engine stalls at 2a.

I have tried this with the MAP sensor disconnected as well.

No sure where to point the finger of blame. Only happens when the engine is up to temperature. The pump re-pressurises immediately when the ign is switched on.

Really puzzled. Can someone help please.

Hey Seamus-

I wouldn't have said this was a fuel-pump issue.

If the pump was struggling; I would have expected it to draw more current as it failed, rather than less; (I must say I'm astonished to hear of the size of values you've quoted there.)

Does the 'Sei' suffer from the crank-sensor failure thing, that other FIATs have? This is often brought about by heat, and offers failures in the manner you describe...

SPi or MPi?

D

dante giacosa said:

Hey Seamus-

I wouldn't have said this was a fuel-pump issue.

If the pump was struggling; I would have expected it to draw more current as it failed, rather than less; (I must say I'm astonished to hear of the size of values you've quoted there.)

Does the 'Sei' suffer from the crank-sensor failure thing, that other FIATs have? This is often brought about by heat, and offers failures in the manner you describe...

Click to expand...

Thanks for the reply.

I agree that it is not the fuel pump. Looking at the wiring diagram it connects next in line to the MAP so have ordered one of those.

Re the current draw, I will have to recheck that though looking at the gauge it the feed wire it looks to be in keeping.

By way of a test I am going to run a feed direct to the pump to see if any other sensors kick in to stop it.

The puzzling bit is that it will restart immediately. The pump starts at once.

Welcome any other thoughts.

rallycinq said:

SPi or MPi?

D

Click to expand...

MPi though not sure of the difference. It is 2002, 1100cc

Seamus2012 said:

MPi though not sure of the difference. It is 2002, 1100cc

Click to expand...

MPi runs at a far higher pump pressure, the fuel filter is also 'in tank' rather than external.

Check the nominals of the temp sensor.

D

I have run MultiEcuScan again today and notice that the "Canister fill" gradually reduces to 0% and then the engine stalls.

Does that give any clues?

Carbon canister issue, would suggest that its filling which would be a too much fuel issue.

Blocked return?

D

I would have thought that reducing to 0% and stalling would mean that it is empty?

According to MES 0% means empty.

I have fitted a new MAP sensor today. It is a bit better in that it is less likely to stall at tickover. The canister fill starts at 0.006% and gradually zeroes. The engine losses power once it is down to 0. I don't really know the purpose of the canister.

The canister traps excess fuel from the injector and stores it in the carbon until such time as the engine is running and then releases it back into the induction system to be burnt.

D

Thanks for the reply. I have looked all over for an explanation. It makes a lot more sense now to see it running down to zero.