Hi guys, long time no post if ever i haven't had a seicento in a while...

long story short i have a 1100cc Seicento LX

basically when it gets hot in traffic it'll bog down almost like its being flooded then cut out under load, i've researched so much about this but i'm stuck

only because it'll cut out then start no problems

it only dies when the car is at full operating temp and under load

some information about the car

New headgasket
New coilpacks
New spark plugs
New HT Leads
New battery
New genuine magnet mirelli Crank sensor (thought this was the issue initially)
New Green water temp sensor

it has a FLEXICAP petrol cap which doesnt look like its sealing that well, could this be the problem?

heres a youtube clip to show whats going on, my foot is flat on the accelerator....



Any help is massively appreciated!!

There is no engine code stored or even pending???

Sam

Just from experience, Crank sensor or called TDC sensor.

thanks for the reply

Thats what i initially thought so went and got a brand new one from euro car parts fitted it and still have the same issue... you don't think it could be a faulty new part?

sam7986 said:

thanks for the reply

Thats what i initially thought so went and got a brand new one from euro car parts fitted it and still have the same issue... you don't think it could be a faulty new part?

Click to expand...

My bad, should have read your post properly first!

I would suspect the blue temp sensor, but the fact that no codes are being stored made me think it isn't that.

This is MPI, does it have the micro ECU?

P.S, i still do strongly believe is the Crank sensor, but is not worth chancing buying another.

thanks fro replying again!

i replaced the green temp sensor with a brand new part this morning still no difference

i still suspect the crank sensor but perhaps it could be the cam sensor?

tested the crank sensor with a lighter and a multimeter and its values climb, doesnt drop to zero ohms at all :/

it has an ecu but not sure if its micro?

very confused indeed

when i went to euro car parts they had 2 cranks sensors to choose from relating to engine number

i couldnt find the engine number but they only had one listed for a genuine part so went with that, it starts drives and runs fine, but when it gets hot just bogs down and cuts out :'(

The video doesn't work.

Why do people just replace stuff willy nilly? To test If it is the TDC sensor, wait till it conks. While hot, remove one spark plug, re-connect the lead, lay it on the rocker cover, get someone to crank the engine. If it sparks, the TDC sensor is OK. If it doesn't, get the helper to crank the engine some more, pull another plug. If it's dry, rather than petrol smelly wet, then the TDC sensor is flooked.

To reprise -- a fubar TDC sensor will result in no fuel past the injector(s) and no spark.

ive just checked the part numbers on the crank sensors...

the original magnet marelli sensor is stamped 46778331
the new magnet marelli sensor is stamped 55189514

but the car still runs fine until hot, is this the issue?

try that?

i can see the video but thats no good!

for the previous poster, it has a micro ECU as it is incredibly small!

before i go removing the airbox can anyone confirm different crank sensor part numbers would cause this issue?

Test it, man.

TDC sensors and coils are known for breaking down when hot. But it's not a precise science.

Part numbers change -- FIAT (at least) -- have had 2 sets of part numbers running concurrently.

Personally I'd not buy anything other than oil, filters and NGKs ftom EuroCarParts: eurocarcare and Shop4Parts (or even a local factor) will generally give tou better parts and service.

I did post up the test resistances for the TDC sensors a while back -- a search (advanced search, m user name, TDC sensor) should snag it. I'd re-post but don't have the book here.

so pulled a spark plug, plug is dry, started it, missfiring and sounding like a tractor the plug on the rocker wasnt sparking!

From my last search for TDC sensor, the differences in part number only relates to the length of the cable !

I was searching for one with the longest cable and cinquecento has that.

so because the plugs are dry the sensor i've just bought for £30 is faulty?

seems odd that a brand new genuine part doesnt work...

but the plugs are dry and its not sparking so thats 100% the TDC sensor??

I'd guess you have a coil pack out. 1 and 4, 2 and 3 should share a coil pack. With the evil micro ECUs it's wise to replace coil packs as a pair.

Still, you might try the counterpart of the non-firing plug, check that's flooked. If so, swap both of the spark leads, so that 1 and 4 are to the coil pack which was 2 and 3 and the reverse, try again. If the fault jumps cylinders, you've confirmed, pretty much, that the coil pack was the issue.

Bit worried by this talk of removing airbox to get at TDC sensor.........?

hi mate thanks for your help, the airbox was removed to get to the spark plugs not the ~TDC~ sensor.

ive just replaced the coilpacks with the original ones that came with the car in the boot and the problem is still evident, even tried one coilpack of each but to no avail

this thing is pi**ing me off now

reckon its a duff TDC sensor?

I have my doubts.

In the Punto Guides/FAQs there are some tests for a fubar ECU. (Mk2 Punto uses the same POJ as the early MPI Sei).

But in all this, you have to sit down, bit of paper in hand, work out the logic.

If it fires on any cylinder (or sparks on any cylinder) when hot, it won't be the TDC sensor.

It's starting to sound like it is the Ecu. Where are you located as I have an unlocked test Ecu.

The good news (in so far as there can be good news) is that a rebuilt ECU can be bought (if that turns out to be the issue).

I count myself very lucky in that I've always managed to avoid the early MPI ECU.

i'm in the south east pal

Tunbridge Wells in Kent

what would i need if i were to replace?

immobilisers and keys etc?

basically the car was sold to this guy sold as seen, he tested it, drove fine and took it home, i get a call the next morning saying he wants a full refund

1. i've already spent the money...
2. private sale so he has no leg to stand on apart from anger

i said ill offer my experience but he'll have to pay for parts as at the end of the day its his problem now but i don't understand how its broken overnight...

thoughts if i were to just send him the link to this?

bit wary how it says self coding though...

http://www.ebay.co.uk/itm/FIAT-SEIC...arts_Vehicles_CarParts_SM&hash=item2ed711df66