Fiat Fiat Seicento 0.9 899Cc 1994 Throttle Body Single Point Injection Unit

Hi, Got a problem with my Seicento. Driving along fine ( engine is warm and been driving for about 15 minutes) and stop at a T junction ( on a slight rise). Engine stalls. I try and start, nothing, engine turns over fine but will not fire, as if run out of petrol. I put more petrol in, still won't fire. after about 45 minutes try again, after copious amounts of trying, engine fires up, runs perfectly fine for maybe 20 - 30 seconds or so, stalls. won't restart
RAC(breakdown) man takes the Single Point Injection Unit apart, we turn over fuel pump is working fine. Try and start again with the cover off.
After maybe a minute of turning over on the battery - injector seems to backfire a couple of times , then nothing but the engine turning over - good job I've got a good battery !
I was towed to my garage who can't diagnose the problem. his only solution is to replace the entire Single Point Injection Unit assembly and see if that works - if I can find one 2nd hand that is from a scrapper, that is!

Has anyone else had this problem and has any idea what it is ? - car was fine, then cut out on a run and won't restart.

Problem getting spare parts and I may have to scrap it,if I can't resolve so any help would be appreciated. Loads of Punto Single Point Injection Unit's for sale on web -Are they the same as in a Seicento? Seicento ones seem to be as rare as hens teeth !!

Thanks

Disappointing that they seem to have focussed on the injection unit, as these are very reliable.

More likely to be a crankshaft sensor. These do fail, and often when they get hot, working again as they cool, which would fit your symptoms.
Coil packs can also give up, but there should be no need to replace anything just to find out. Needs proper diagnostic first, but as this is pre-OBD11, it needs Fiat specific plug and software. The diagnostic plug is a 3-pin, then an adaptor is needed to connect this to the computer. There is a great diagnostic software called MultiECUscan, search for threads about this.
Plus here's their website. http://www.multiecuscan.net/SupportedVehiclesList.aspx

Advise your location, someone might be local with MES and the correct cable.

portland_bill said:

Disappointing that they seem to have focussed on the injection unit, as these are very reliable.

More likely to be a crankshaft sensor. These do fail, and often when they get hot, working again as they cool, which would fit your symptoms.
Coil packs can also give up, but there should be no need to replace anything just to find out. Needs proper diagnostic first, but as this is pre-OBD11, it needs Fiat specific plug and software. The diagnostic plug is a 3-pin, then an adaptor is needed to connect this to the computer. There is a great diagnostic software called MultiECUscan, search for threads about this.
Plus here's their website.

Advise your location, someone might be local with MES and the correct cable.

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Thanks Portland - Interstingly it was a very hot day when it stalled - so hot I first thought that the petrol was evaporating somewhere in a pipe ( or similar prior to getting to the injector !

Location is Baldock Hertfordshire SG7

Thanks

Big chance its the crank sensor. just change it for a new one they're dirt cheap.

LeonL said:

Big chance its the crank sensor. just change it for a new one they're dirt cheap.

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OK Update , Car still at the garage/ Fiat turns over fine but still not start.Had a chat with the garage today, they have completely checked over the fiat, injector assembly, wiring loom crankshaft sensor ( and replaced). The fuel pump is fine BTW.

They say there is no spark being generated anywhere and are at a complete loss to find out whats wrong. They said it would be completely unlikely that both starter coils would fail at the same time.

Any help advice would be more than welcome as my only option at the moment will be soon to have the car towed home,as its clogging up the garage, put on my driveway until I myself can try and work out whats wrong with it - or scrap it. It seems so crazy, car was absolutely fine, there is nothing wrong with it except it won't start !!

Help!!

24grange said:

They say there is no spark being generated anywhere and are at a complete loss to find out whats wrong.

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That is a very disappointing statement form a Fiat dealer, or any garage.

A coil needs a live feed and an earth, that is then switched to create the spark.
Their diagnostic machine should show if the ECU is switching the coils, but simple tests can diagnose it.

I believe the ECU switches the earth, or return, wire from the coil.
So there should be a live feed to each coil, and a measurable switching of the other wire. Simple voltmeter stuff.
If the coils are not being switched, fault lies in wiring, connections, or ECU. If they're being switched, but not producing a spark, the coils are dead.

Whilst we're thinking simple checks, the cambelt timing should be checked. If it has jumped a few teeth, that would prevent it running. A seizing water pump can cause this.

portland_bill said:

Whilst we're thinking simple checks, the cambelt timing should be checked. If it has jumped a few teeth, that would prevent it running. A seizing water pump can cause this.

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No belt on an 899, but, yes, check the supply to the coils and report back.

D

Really stupid thought....have you triggered the crash switch?

Press it and make sure

D

rallycinq said:

No belt on an 899, ....

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Good thinking. Perhaps I should have gone to bed earlier, instead of browsing the forum.

rallycinq said:

Really stupid thought....have you triggered the crash switch?

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That's a very good thought.

Thanks - were and what is the "crash switch?" never heard of it?

Thanks for all the advice to date

There is an inertia switch that cuts off the fuel supply in the event of a collision. Not sure whether it also stops ignition, but without fuel it won't start anyway, so this is worth checking. These can be a little over-sensitive, triggering with a violent stall.

Your handbook will tell you exactly where it is. I think it is listed under Fire Protection System.

A long time since I owned a Sei, so here's a guess. You are looking for a button to press. Probably about 1.5-2cm diameter. Under the passenger seat, or the driver's seat, near the front. Or under the centre of the dash, just beside your left foot, or perhaps the right foot of the passenger.