Technical Juddering & cutting out - Mpi injectors coils or fuel pump?

[Smiler121]

As some of you may know I run a Seicento Mpi but my girlfriend's 1242 Mpi Punto has been struggling & juddering since Christmas - particularly at higher revs in anything over 1st gear, especially under full throttle applications so I swapped plugs, did the cam cover leak & an oil change hoping the plugs would help. The clutch then packed up completely so I hoped that it may all have been a result of slipping badly.

I don't drive it regularly & she continually downplays faults saying it feels like things are fixed every time I try something (I think that her sensible low speed driving masks the issue as she barely revs the car) :bang:

I have put a full tank of fuel dosed appropriately with Redex through the engine with no improvement so I changed the leads the other night & the car started stuggling to start, requiring high revs to stay running & then cutting out, swapped them back & it has continued cutting out so I am at a loose end

Am aware that it is likely to be fuel filter/pump, coils or injectors but need a professional to help diagnose which (have a qualified mate coming round tonight to try).

We have a baby on the way as well as having absolutely loads of ca$h to shell out as we have no choice but to move house so I have a few questions for anyone that may be in the know - I have a load of old parts from my original Seicento that was written off a while back so...

Does anybody know if the injectors on a mk2 1242 mpi punto are interchangeable with those from a 1108 Mpi Seicento?

I can't convince myself if the noise from the pump priming is loud enough 'cos in my Seicento it is really noticeable, is there definately no way of cleaning/replacing the filter in a Mpi fuel tank other that a swap of the pump, & if so does anyone know if the pump from my Seicento Mpi can be used.

Are the coil packs on my Mpi Sei interchangeable with the Punto?

 

[rallycinq]

Open the bonnet in the dark, check for stray sparks.

When the engine fails, are the plugs wet or dry?

Cheers

D

 

[ycming]

Well in my cinq am using a punto 1.2 16v fuel pump and fited in perfectly .

You just have to remove the actual pump itself from the plastic stuff.

Ming

 

[fingers99]

I've yet to come across either failure. I'd go Rallycinq's route and look at the ignition first -- it's cheaper, easier, and more likely.

 

[Ralf S.]

Rather than changing things at random, try some simple diagnosis first.

It sounds like it's a coil problem so confirm this by laying a spare plug on the cam cover to earth it .. then connect one HT lead at a time to it. See if it sparks when the engine is running. If it doesn't, check the other lead attached to the same coil. If both of them don't work, it's that coil. If only one doesn't work, it's either the plug or HT lead.

Do you have fuel at the fuel rail? Disconnect the rubber tube and see if petrol comes out when you crank the engine (do this with a cold engine and make sure you catch any fuel that comes out). It's a much quicker and easier way to diagnose a fuel issue than taking the pump out.

Ralf S.

 

[Smiler121]

Well in my cinq am using a punto 1.2 16v fuel pump and fited in perfectly .

You just have to remove the actual pump itself from the plastic stuff.

Ming

That's handy to know thanks.

I'm not planning to just swap stuff at random but had figured that the service was a good idea either way.

Never had this kind of issue with my car so thanks to everyone for the diagnosis tips, I'll get the plugs out again & take a look at them checking for a spark.

 

[ycming]

Check coil pack first , remove all the leads at coil pack have someone to start the car. You should see sparks on both coils.

Ming