I am having problems with my Seicento engine stuttering whilst driving under load. Stationary it will rev freely.

My thoughts and having read through this forum is that it is a fuel issue. So today have had the back seat out, disconnected the out hose, connected a spare length of hose and spun the engine over to fill a jar. There is no shortage of fuel there so have now gone to the front to do the same there.

I am not familiar with injection systems, more used to diesel. I pulled a hose off the throttle body, see photo top arrow. No fuel came out so I am guessing this is the tank return. The lower one, bottom arrow, I cannot remove. Tried pressing the buttons but can't shift it. All I want to do is to check the fuel is getting up to the front.

So could someone please let me know which hose to remove for testing and how to remove it.

I am guessing that if I cannot fuel through here then it is the filter. Could someone let me know where this is located please.

Thanks for your time.

Before you do anything else, try disconnecting the electrical connector from your MAP.

Lift the bonnet and look on the passenger side of the engine. The MAP in held in position by three bolts and also has a vacuum tube connected.

With the MAP disconnected take the car for a drive. If the stuttering has disappeared - it's pointing towards a faulty MAP.

When spark plugs last renewed?
If old and gap too large under load will misfire.

Thank you.

I assume you mean the 3 wires indicated by the red arrow in the attached.

Pulled the plug and took it for a run and it was fine. Plugged it back in again and it was still ok. Not to say this isn't at fault as this problem has happened before and cured itself. Would your money be on that this is the fault?

I've got old eyes, Seamus and can't make things out in photos like I used to do.. Is that also a vacuum tube connected? If so, that's your MAP.

I have a 1994 900cc Cinquecento, even though I don't remember breaking a mirror .. It had the same problems that you describe.

Sometimes it would start and run okay and at other times - spluttering and jerking enough to rattle your teeth.

I changed the plugs, which made no difference. I took the injection apart, cleaned it - and it made no difference. I even took the fuel pump out of the tank to inspect that and...

... then I disconnected the MAP and took it for a run. No spluttering/missing .. so I changed the MAP and haven't had any problem since then.

They're cheap enough on Ebay .. about £25, and personally I would change it. If the car still sputters at least you know it's not the MAP!

Coil packing up. Cant handle being under load

Glad you've sussed it out. Some of these small, niggling faults can be a real pain.

Thanks for the suggestions.

For the moment it has cured itself and don't want to end up replacing everything in the hope it cures the problem but leaving me unsure in case it hasn't.

The coil is a possibility but my experience from years back is that once faulty they did not right themselves.

The map sensor is a possibility but not have experience of them. Assuming that I have identified the location correctly, the next time it fails I will disconnect it and see if it solves it

If it's any help, I've attached 2 photos of the MAP on my 1994 900c Cinquecento. On this car it's situated near the ECU towards the passenger wing. Note the vacuum tube ..

The OP has an MPi, the 899 is SPi so quite significantly different.

The OP seems to have resolved the issue for the moment and on the MPi, if it has the micro ECU the coil drivers are what fails, but like a coil, these don't fix themselves.

D

Thanks for the feedback.

Took it out today and after about 4 miles the fault is back.

I am enclosing some more pics and the red arrow indicates what I think (from the info you have give) is the MAP sensor. It has a 4 wire connector at the top. When the fault occurred I disconnected the 4 wire plug and continued. It did not cure the problem and in fact made it worse. The car does smell like it is running too rich.

If I stop the car for about 10 seconds I can then carry on without trouble for about 100m, then starts stuttering. To me this seems more like fuel starvation.

Is there point in the engine bay where I can check the fuel flow.

Would welcome any thoughts on this please.

Hopefully rallycing will read your comments - he seems to know a lot about things.

Personally, given the price of a MAP, I'd change it just to see what the result is. The symptoms you describe are identical to what I experienced with my Cinquecento

Yes, could be a solution.

I am a bit confused about the MAP on this car. According to this ebay listing
http://www.ebay.co.uk/sch/i.html?_from=R40&_sacat=0&LH_PrefLoc=1&mvsub=1&_mcatda=true&selfil=2%2C3%2C1%2C9%2C8&selvel=Fiat%7ESeicento%7E2002%7E187%2520%255B1998-2010%255D%2520Hatchback%7E1.1&_nkw=map%20sensor%20Fiat%20Seicento%202002%20187%201.1

There are two types of MAP for this car. One has a 4 wire connection and the other 3 wire. On my car there is a 4 wire held in by bolts and 2 wire connector held in by spring clip. See photo, red arrow shows 4 wire and yellow arrow 2 wire. I am assuming that the top one is that in question.

Sorry about these stupid questions but an not up to date with modern petrol having had diesels for a long time.

You can easily check (though I can't see a MAP that has 4 wires). You can also look here:
http://www.ricambio.co.uk/2487-map-...nto-seicento-punto-mk1-panda-uno-tipo-bravo-a

When you look at a car item on Ebay use the 'See Compatible Vehicles' link. After clicking on the link you will be presented with a further screen where you can enter your car details.

If the part isn't compatible with your vehicle it will tell you so in red letters.

There's no such thing as a stupid question, only an unhelpful or stupid answer.

Here's 2 images to show you how to use 'Check Compatibility':

Thanks for that.

Here is a link for the 4 wire version. It was in the link you provided but not very clear.

http://www.ebay.co.uk/itm/Genuine-F...pe:1.1&hash=item35f4611a31:g:7JgAAOSw0hlZEqjk

There are cheaper ones but this shows the connection more clearly.

Both the 3 and 4 wire versions are shown as correct for this car so Fiat must have changed the design at some stage as can't see wear else it might be fitted.

I have now fitted a new map sensor and there is no difference.

It is ok initially though the pickup is a bit jerky at low speed, but after about 3 miles it starts to stutter - engine dies then picks up then repeats. Coasting and restarting the engine immediately cures it for about 1/2 mile then fails again.

I am a bit stumped as to what to do next.
Doesn't sound like a coil as it would not restore
I can hear the fuel pump pressurising at each switch on. Is there something that cause the pump to work intermittently?

Please help to get this car working again.

Thanks

Lambda sensor in the exhaust maybe, the front one controls fuelling it could be knackered.

The simple answer is to get the leads and plug it in to your laptop....but in the meantime.

The lack of a management light would suggest that the management system thinks everything is ok.

If it was over, or under fueling, the ecu would try and adjust within the parameters of the map. If it couldn't resolve then it would put the management light on.

I would be heading towards crank sensor or its wiring.

D

Thanks for the suggestions.

I have tried the Multiecuscan software but am not getting any readings from it.

I have got the VAG connector but the only socket I can find is by the drivers right leg. Is this correct? I was expecting to find a smaller connector in the engine bay but cannot find anything resembling the socket.

Could someone point me in the correct direction please.

Sei MPi should be OBD2 and under the dash. The earlier SPI cars were a 3 pin socket in the engine bay.

D