Hi

My Seicento MPI sporting is playing up ..

Car was running fine, then the morning after driving 100 miles in the pouring rain, i went to start it and the engine light came on and stayed on, car started but seems to be not running on all cylinders

The car has a couple of other problems that have been there for a while (i really need to sort them) the water rail is leaking a bit and the cam end gasket/rubber has a slight leak, not sure if the water has dripped on to a connector or such

Any ideas guys??

Thanks

Mike

The misfire will be causing the light to come on, not the other way round.

With insulated pliers, remove and refit each plug lead in turn and identify which cylinders are misfiring.

Go from there.

Cheers

D

rallycinq said:

The misfire will be causing the light to come on, not the other way round.

With insulated pliers, remove and refit each plug lead in turn and identify which cylinders are misfiring.

Go from there.

Cheers

D

Click to expand...

Ok thanks I will try this..

To be honest, I am not sure it's a misfire. When in the drive engine running and you put your foot on the throttle, it just runs badly, sort of chugging sound..if that makes sense!

Could it be a sensor or the ecu?

Thanks

Mike

Try replacing the HT leads, easy quick task. And only costs about £10 if that.
Wait till it gets dark, which seems to be never with these long days.. and check for the blue sparks, they can look like Christmas lights on your leads

Andy

Andy2011 said:

Try replacing the HT leads, easy quick task. And only costs about £10 if that.
Wait till it gets dark, which seems to be never with these long days.. and check for the blue sparks, they can look like Christmas lights on your leads

Andy

Click to expand...

Thanks Andy

Will have a look tonight for blue sparks then go from there

I just bought a set of plugs and leads from my local motor factor £14.00 not much to rule out a runing problem. It would quite likely be high tension problem especially if it started when the engine may have been damp from driving through standing water at speed.

Ok, it;s not dark so can't see sparks of course . But ..

I removed each HT lead in turn from the coils and started the engine

First cylinder (front left as looking at engine) made no difference, engine still lumpy

Second cylinder made it worse, third same as when all leads attached, fourth made it worse ..well i think thats right..

Funnily enough when i re-connected them all, it started and ran perfectly, could rev the engine, all smooth for 10-15 secs then rough again, i managed to re-create this several times by undoing the leads then re-conncting them, but never got it to stay fine.

So is this the leads?

Cheers

Mike

Sounds like the leads. Replacing the set would be wise

Eurocar parts (normally abit over the odds) have a offer on atm, type 'MIDMONTH30' at the checkout and you get 30% off

P.S. Dont be afraid to give it a good tug and yank when removing the spark plug end
Edit: Not the end which is easiest to pull off, but the ones under the airfilter

Thanks for that Andy, will check out that offer

Mike

spray some wd40 on all the connections to make sure no water in there

Ok, so i replaced the HT leads and sprayed wd40 on connectors etc

Still misfiring

When i unplug the ht leads from the rear coil, it makes no difference to the running of the engine, do the same to the front and the engine will not start, so the rear coil is at fault yeah ..

Or is it ..

reading on the forum it seems the ecu could be faulty, and i may have to change the ecu and the coils

Any more advice

thanks

Mike

nsr500rossi said:

Ok, so i replaced the HT leads and sprayed wd40 on connectors etc

Still misfiring

When i unplug the ht leads from the rear coil, it makes no difference to the running of the engine, do the same to the front and the engine will not start, so the rear coil is at fault yeah ..

Or is it ..

reading on the forum it seems the ecu could be faulty, and i may have to change the ecu and the coils

Any more advice

thanks

Mike

Click to expand...

Swap the coils over. If the fault follows them its just one coil and the ecu is ok. If not then then its ecu and at least one coil.


If it is the ecu then you may be able to send it for repair rather than get a replacement.

DannyCento said:

Swap the coils over. If the fault follows them its just one coil and the ecu is ok. If not then then its ecu and at least one coil.


If it is the ecu then you may be able to send it for repair rather than get a replacement.

Click to expand...

Ok so i swapped the ht leads from one coil to the other, also swapped the connectors with the small wires, started the car, still doing the same thing.

I am confused to what i should see

Am i doing it right

you actually need to swap the coils over really for that test not just swap the leads. But it is highly likely to the be coil rather than the ecu..

Ok, why though, if i swap the ht leads and the connectors then is that not just the same?

And why is the conclusion that it ran just the same, i don't understand how i can tell if it's the ecu by swapping the coils, it's only going to run the same as one coil is not working.

I am ready to be shot down here i think, so sorry, clearly i am a bit lost on this one

M

nsr500rossi said:

Ok, why though, if i swap the ht leads and the connectors then is that not just the same?

And why is the conclusion that it ran just the same, i don't understand how i can tell if it's the ecu by swapping the coils, it's only going to run the same as one coil is not working.

I am ready to be shot down here i think, so sorry, clearly i am a bit lost on this one

M

Click to expand...

Yes it is the same because you moved both the low tension and high tension leads.

As a final check, move the small plugs only, then the fault should move to the other coil if its the ecu.

Cheers

D

I did try that earlier, the engine would not fire at all

Does that mean it's just the one Coil at fault then..

Thanks

M

One coil will spark 1 and 3 the other will spark 2 and 4. It does sound like a coil pack has gone.

nsr500rossi said:

And why is the conclusion that it ran just the same, i don't understand how i can tell if it's the ecu by swapping the coils, it's only going to run the same as one coil is not working.


M

Click to expand...

The way I've always understood it the ecu gets damaged if there's a particular type of fault with the coil. It permenantly looses the ability to fire 2 cylinders, effectively the 2 that the faulty coil served. The coil remains faulty. By swapping the coils you're looking to see if the car still runs on 2 cylinders - if it does then it's only one coil pack at fault because the ecu still has the ability to fire all 4 cylinders - you prove it if the cylinders that didn't fire are now firing, so the ecu is fine in that instance.

If the car doesn't fire after swapping coils then it could well be that the ecu is damaged and can't fire 2 cylinders, plus one coil is broken so doesn't fire the other 2 cylinders. So no cylinders are firing as there is no spark from the plugs.

Best way to know for sure is to whip all the plugs out, connect to the ht leads, ground them on the head, and watch for sparks whilst you do your testing.

You could buy a coil now and fit it, they're not too expensive, but if by testing you find your ecu requires repair and it turns out too expensive to repair/replace for you then you save yourself the money on the coil.

At least i think that's what happens!

They are wanting to test the coil packs, if the coil packs are fine and you are getting fuel. Then i would get a compression test done!

Ming