Hi all,

My Cinquecento Sporting, 1108cc, 1998, recently started this fault. I did a bit of boards searching but didn't find anything conclusive, so I thought I'd ask .

It's single point injection but has the GSR inlet and cone filter. Last year I had to change the head gasket and cleaned the breather filter blocked with 'mayo', had the head skimmed. Fitted the 866 cam and shimmed it very well. It ran very smoothly after all that.

Would the ECU be too early, 1998, to have the fault code thing?

It still starts OK from cold but is now rough / missing on idle and low speed, with light flashing instead of steady, and staying on. Those states would continue until I'd driven a mile or two, the roughness then going smooth and the light going off.

Now it lasts longer and is cutting badly at speed on the dual carriadgeway. A bit similar in feel to the rev limiter, or whatever goes on there at about 7000rpm.

The boards suggested:
MAP,
Water temp,
Lambda,
Injector,
Crank position sensor.
(Throttle position sensor)?
(Coil Pack)?

The fault would seem to be affected by engine temperature or/and runnung time.

Water temp goes up a bit, but probably not much in only 1 mile.
MAP unit itself could heat.
Air temp sensor in the throttle body?
Crank position istelf could heat.
Lambda does heat. Is that input ignored by the ECU until water temp is up? Or timed delay? Or measuring straight away? Some delay as has to heat up to work?

In the last 2000 miles or so I fitted new MAP and new water temp sensors.
I measured the air temp sensor and it's Ohms were within the stated limits.
Lambda is about 6000 miles, or less. IS the NGK NTK OZA527-E19 (0296).

AFAIK, the crank posn sensor is the original.

Thanks.

No, the ECU is not too early to read faults. Your lists contains essentially all the ECU can discover in terms of sensors / actuators (there are also functional trouble codes). The cable (VAG KKL + Fiat 3-pin adapter) costs peanuts these days, software is for free (IAW ECU Scan (II)). It will save you hours of guessing and replacing components A general thing that you should check (ECU will not tell you it is a problem and get confused otherwise) is all earth points and connections. Especially when you took the head out for HG replacement you could have forgotten / damaged the small earth connection at the back of the head.

Thanks for that

I don't have a laptop PC, tablet, any anything like that, nor can I borrow one. Desktop PC here, so can't use that.

Is there a cheap fault code reader I can just plug into the three pin socket? And list of the codes?

I noticed something just now:
From switch on, red light as normal, few seconds, goes off, as normal. But a few seconds later it comes on flashing.

That would rule out some things as it's not temperature related. Unless that merely shows a fault was logged some time earlier, perhaps when the engine was running, and not that the fault is present when the light flashes at that moment?

Found this list: https://www.fiatforum.com/tech-talk/197403-eobd-error-code-list.html

Also found a post saying that older Centos don't use standard codes but Fiat's own codes. Would that apply to my 1998 car?

My gut feeling reading the symptoms is more away from sensors themselves (albeit crank sensor would be worth swapping), and more into vacuum type issues. Some kind of leak, most likely the pipe leading to the MAP sensor. They are prone to cracking and splitting.

Have you done the Phonic wheel re-learn after engine re-build?

Had something similar years ago, it was the spark plug leads.

Thanks for your replies

woj said:

No, the ECU is not too early to read faults.

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Local Fiat main dealer wanted minimum charge of £114 just to plug the reader and have a look. Their Throttle Position Sensor price is about £120, I paid £9 from eBay for a new unbranded one with two year warranty!! (And they're making a profit out of that £9 and paying taxes, shipping, etc.) I read somewhere that the fault codes of the older ECUs are 'secret' to Fiat and third party readers might not say the meaning of the code.

woj said:

earth points and connections. Especially when you took the head out for HG replacement you could have forgotten / damaged the small earth connection at the back of the head.

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I have checked earth points previously. If there was one behind the head then I would not have missed it, I'm meticulous and thorough with things, more like a scientist in a lab than some mechanics in a garage.

cc1 said:

Have you done the Phonic wheel re-learn after engine re-build?

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No. What is that? However it worked very well indeed after the head gasket, camahaft and reshim a year ago. The faults started a few weeks ago.

mrcinquecento said:

My gut feeling reading the symptoms is more away from sensors themselves (albeit crank sensor would be worth swapping), and more into vacuum type issues. Some kind of leak, most likely the pipe leading to the MAP sensor. They are prone to cracking and splitting.

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Hoses consist of a hard plastic straight pipe and a rubber 90° hose at each end. All are in very good condidtion. Leaks tend to be consistent and not varing in the way these issues are, and then there's the red light. Which leaks would cause the ECU to turn on, or flash the light with this model and year of car?

EPa said:

Had something similar years ago, it was the spark plug leads.

Click to expand...

Did that turn on the red light? My leads are good condition Magnecore KV85. Plugs were OK last time I looked, only done 1000 miles since. I did have a continuous rough idle when I bought the car and I eventually found that was one or two of the OE leads had gone faulty.


The status so far is I've swapped, measured, replaced more parts but had no effect on the red light, the problem starting, the bad idle or cutting out after starting.

I've changed or measured:
Lambda; for an old one, I just plugged it in but the red light stayed on so I reverted to the existing one.
TDC / crank position; new from Eurocarparts. No change in anything. New one measures about 1100 Ohms, old one; about 600 Ohms.
Water temp, was new a couple of years ago.
MAP; now reverted to original, as I removed the rubber pipe from the new one the hose barb simply snapped off!!
TPS; measured, and a new one that measured about the same is fitted. £9 from eBay.
Air temp; measured, about 600 Ohms.
Idle speed stepper; seemed to be working as the idle is about 1500 for a few secons then drops to about 1000, as always has.
ECU; changed for another. Worked mostly. Difficult to start one time. Red light on, but not flashing at all. Rough and not stable at idle and idle also keeps dipping in revs every minute or so. However so far it revs all the way past 6000 whereas the existing one was rev limiting to 4500rpm. So was the old ECU going wrong? The red light has goine out a coupleof times with this one, but come back on and stays on once ign key is turned off and then engine is restarted.

Not changed:
Coils x 2. I did measure the resistance. ECU could monitor the resistance.
Fuel injector. ECU could monitor the resistance.
Purge solenoid. ECU could monitor the resistance.

Could these turn on the ECU light? It would have to sense / montior / measure the resistance and or current flow to earth of these to know anything was abnormal. Can and does it do that?

I starting to wonder if this could be the end of this car.

It also needs:
Rear wheel bearing.
Headlights. The reflectors are crazed and dull.
Fuel filler under the cap has come unstuck.
Gearbox noise / low oil? Might input shaft bearing. I can't get under there any more to check oil, etc. Local garage wanted silly money to do anything with the gearbox.
No speedo as the plastic cog broke in the gearbox it seems. I've been using a GPS one with Odometer.
Wheel rebalance and tracking.
Seems to leak around the front of the rear side windows and very wet into the boot. No rust anywhere in there so not the normal hole.
Rear trailing arm bushes knock a bit.
What else? Something breaks every few miles. Today the drivers door lock jammed unlocked and the key wouldn't turn and the button wouldn't push down.

I've been tipping money into this car for years trying to keep it going, it's only 55000 miles or so, I'm only the third own and the second one is a pal of mine, a classic car specialist, I have all the receipts from new and full service history, it evidently been well looked after since new but it keeps surprising me with yet more stupid failures. It's getting me down and I have started look for a suitable replacement car.

One plus point seems to be I may have fixed the erratic and slow door locks that last week went into a cycle of locking and unlocking on their own maybe 20 times. I began to think it would only stop when something burns out. I traced the relay by it nois and vibration to be the yellow box above the passenger footwell. Sadly the socket partly broke to bit as I pulled off the relay module But I foun within it an electrolytic capacitor. I removed and measued it and it came to it rating or 10uF, so OK then?? I replaced it with a much better type, conductive polymer, of the same value 10uf 25V. Refitted to the dangling yellow remnant of a connector, the locks now respond promply to the key or door button as they once did

Ian S said:

Did that turn on the red light? My leads are good condition Magnecore KV85. Plugs were OK last time I looked, only done 1000 miles since. I did have a continuous rough idle when I bought the car and I eventually found that was one or two of the OE leads had gone faulty.

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Yes, the light and engine behaved exactly like you say. Light flashing and engine unwilling, then later while driving symptoms going away and coming back randomly. With the light flashing.

You changed so many things. I think leads usually "look good" even when damaged. You changed so many things, isn't there an easy way to just test some other leads without buying, a friend maybe?

That's interesting. Thanks.

leads usually "look good" even when damaged

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That was true of the OE ones I replaced. Until one of the spark plug connectors came away from the lead revealing a lot of corrosion in there.

An odd thing with my car; a few years ago tried some non resistive plugs, NGK three earth electrode type, 7 heat range, and pre-gapped to 0.9mm (36 thou) together with non resistive copper cored leads, each with a 10k Ohms resistor in series in a cap at the spark plug end.

That should have provided a matching impedance, and matching ignition timing, to all cylinders, and indeed, the higher revs were a lot smoother, but at idle it just popped and banged and wouldn't run. I never found out why. I didn't notice if the red light it came on then. I'm not sure those plugs can be re-gapped, the earth electrodes are shorter than normal as they are at the sides of the centre electrode. Maybe I'll try squeezing one in a bit and if that is OK, I'll try those leads and plugs again.

Unfortunately I don't know anyone with one of these cars that I can borrow parts from to test with. These are now a rare car here Eastern London. Some years since I last saw a Cinquecento or a Sei. The small specialist Alpha / Fiat garage I used until last month, when they stopped trading, had someone working there who had several Cinq's but he moved away a few years ago.

Ian S said:

Repaired the erratic and slow door locks.....conductive polymer capacitor of the same value 10uf 25V

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For the sake of correctness I'm updating the above post here as I can't edit that now.

I was referring to the capacitance more than the voltage. The original voltage was 50V, not 25V. I didn't have a 10uF at 50V in stock and the normal maximum DC voltage in my car seems to be about 14.5V. Maybe Fiat did that in case of alternator regulator failure, but even then, would they need a 50V? The ECU I just took apart also has 50V electrolytic capacitors; two 220uF.

Door locks back to just as faulty as slow as they were, and did the repeated locking unlocking thing again.

Regarding the ECU codes, I found a garage with the correct equipment and he read the many 'historical' codes off, cleared them and now I have to take it back next week with the lastest codes as the red light has been on.

Further, mostly it starts and works OK, idles a bit high.

Drove to a local shop, then it wouldn't start, so undid the fuel filler cap to let out any fuel tank pressure. No difference. Left the key turned and after 10 or 20 seconds a chamber fired, then again, let off the key and it just about ran, then got going but idled steadily at 5000rpm !!! Then dropped but then rose again to a steady 4500rpm.

Eventually it became steady at about 1500rpm and I drove it home.

Sometimes the idle has be going up and down between, say, 2000 and 1200. And other times it steady at 1000 but has a momentary dip every maybe 20 seconds, as if the fan has cut in, which it hasn't.

Do any of you chaps have any clue as to what's wrong with this? And how if can be fixed?

Thanks if you can help.

Lambda sensor does not read until warm. Therefore if these problems are happening immediately, then its not that or anything to do with a dodgy temp sensor.

Crank sensor is a prime suspect.

High idle is usually air related. There are several vacuum tubes going into the TB, make sure they are all intact. Remove them and blow down them while holding a finger over the end. Eyeball is not a good enough test machine.

I would suggest that you do not drive the car until you resolve the gearbox issue. It does not need a ramp to do anything. Remove plug on front face of gearbox and attempt to add oil. My worry is that the noise and lack of speedo would suggest failed diff bearings.

Cheers

D

OK, so there have been a few developments since my last post.

The local Alfa and Fiat specialist who has the Fiat Examiner and read the codes off for me again after I'd driven the car until the red lamp came on a few times; Coolant temp sensor and Lambda Sensor.

As the coolant one was fairly new and came from, if I recall correctly, Ricambi in a printed box marked Facet, not at all cheap looking, I presumed it should be OK so, as he advised, spent some time checking continuity of the wiring to and from the sensor. All was OK. So I changed the sensor for the original 18 year old original one and the car immediately started instantly in the way it always had and ran smoothly with no nonsense at all. It hard to believe that the ECU would or could cause such appalling behaviour just because that one sensor had gone high resistance! Maybe high idle could be expected as it presumes the engine is cold, but none of the other ridiculousness.

So, I drove somewhere for 10 miles and it went nicely. Half way back and it suddenly cut out on the dual carriageway.

Got a tow home. Wouldn't start at all. Next day, checked the new TDC sensor as the other new sensors had failed nearly straight away, but that seemed OK. So did some more continuity testing and found there was no voltage to the coils; blue wire, should be +12 from the white relays module near the ECU. This also feeds a few other things.

Ascertained that there is voltage at the supply pins to the relay from the 20amp fuse and from the ECU. Seems one coil might not be working. Today I traced the continuity to the ECU plug, all that seems OK. With the ECU removed, I tried to energise the coil with a +12 to one side and earth to the other but before I applied the +12, with just the earth, there appeared +12 at the coils blue wire and something in the throttle body made a constant whirring noise. I checked the pins twice and I can't explain why they powered up with no feed at all and just one side of the relay coil earthed.

I've just checked the white double relay module and all seems well in there.

What do you all think about this weirdness?

I'm wondering now if the immobiliser is the cause of the engine shut off as when I earthed pin 23 of the ECU connector (pin7 of the white relay) and everything powered up, the only thing joined to that was the immobiliser, so was that supplying the power during the test and not supplying during normal running?

I'm at the point now where I'm going to scrap the car.

I've had enough. I need a working reliable car that can easily and cheaply be diagnosed and fixed if a fault does occurs, which hopefully it wont. If I get this trailered to a garage that is willing to take it on, that plus the the cost of so many hours of diagnosis, the value of the car would be probably be far exceeded. And it needs maybe £900 of stuff doing apart from that.



Thanks for having a go at this problem

rallycinq said:

Lambda sensor does not read until warm. Therefore if these problems are happening immediately, then its not that or anything to do with a dodgy temp sensor.

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When I fitted this 4>2>1 exhaust manifold a few years ago, I had to try two Lamda sensors as from setting from from cold, with the Bosch fitted, the engine would not run well at all, however with the NTK, it did, even though the heater in that did not have continuity, so was perhaps not working. So my ECU did seem to be affected by the Lamda more or less straight away. It's had a McCrich chipped ECU, if that's relevant at all.

rallycinq said:

Crank sensor is a prime suspect.

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I already changed that with no effect. That wasn't the problem, but a few people suggested it was.

rallycinq said:

High idle is usually air related. There are several vacuum tubes going into the TB, make sure they are all intact. Remove them and blow down them while holding a finger over the end. Eyeball is not a good enough test machine.

Click to expand...

With my car the idle drops with there is an air leak into the inlet manifold. I double checked by taking off the MAP feed, and it dropped. So I guess the ecu senses the throttle posn is closed and does not rev up when idle vacuum is reduced or lost.

rallycinq said:

I would suggest that you do not drive the car until you resolve the gearbox issue. It does not need a ramp to do anything. Remove plug on front face of gearbox and attempt to add oil. My worry is that the noise and lack of speedo would suggest failed diff bearings.

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I have no choice there, it's my only car so I have to drive it. I couldn't see any oil filler on the front. The Haynes says it's at the rear for this car, out of site or access from the top, which is rubbish. A couple of mechanics that work with Fiats and Alfas separately suggested it was the input shaft bearing as that was common with these gearboxes and that the oil level would be OK if they checked.