Hey chaps I have a Cinq problem.
Before I get shot for blasphemy, the engine is the same for gods sake.
My sporting is misbehaving with what at first seems like cassic fuel blockage problems.
Power one minute, push the loud pedal down and it dies, ease off Or stop and at tick over it keeps running.
Problem is on way home same symptoms, but clouds of fumes from exhaust, engine rough and management light came on.
I turned the engine off and restarted, drove away slowly and eventually the management light went off.
Where would you look?
Car has just passed MOT but struggled to pass emission test.

Vern and John, put those pants on the outside and come up with a reply.

Cheers Dave

well if the "injector" light came on..its detecting something not right. so the fact the ECU knows theres a fault is a good thing!

now my main thought there is un-burnt fuel.. that makes me think that power to the coils has failed.. it seems the injector was still firing which leads me to think that the crank sensor was still working fine. (if the crank position sensor or CPS ever fails, you do not get any spark or injector firing)

these engines use a twin coil pack system.. so one of the coil packs could be on the way out.. if you have a friendly scrap yard local just grab a set off any punto with a FIRE engine as they all fit and work the same. swap them over, and see if that fixes it.

it could also be down to something as silly as the engine to body to battery earth strap has failed, or is starting to fail. try driving it around with a jumper cable attached to the engine and negative battery terminal then use the other jumper cable and also attach it to the engine, and then to the chassis of the car. see if that stops it. (both cables are going to be used on the negative side. in this test the colours of the jumper cables mean nothing!)

they would be my main "look at" points for this fault.

it could also be some other things.. but i still think its a spark/ignition issue.

a sensor is not.. sensing. it could be a lambda fault.. it may be having connection issues unplug it and see what happens.. running it unplugged with make the car just run as if the "choke" was on. if it still has any issues move onto the next..

now try the MAP sensor otherwise known as the vacuum sensor. if the pipe to this has split, it will cause the engine to be quite hesitant. the pipe will be a very thin plastic pipe.. but the ends are where it splits. just cut it back till the split is gone and re-attach.

most reasons for a car to fail emission tests is because it has some kind of leak in the intake manifold or throttle body.. like a vacuum pipe has split.
a blowing exhaust (or failed exhaust gasket) can also cause a world of issues on the emission test making the exhaust O2/Lambda levels read high.

out of interest, what was the emission levels?
if you have high HC (hydrocarbon) levels it is due to over fuelling, or fuel not being burnt enough in the cylinder (caused by spark issues or very late ignition timing)
if you have high O2 (Lambda) readings it is because you have part of the air flow system open to atmosphere as stated above
(not really necessary for us lot with petrols, but if you have a diesel that smokes, its normally caused by a leak in the pipe that connects the turbo to the intake manifold)

that is about it.. other than doing the old "unplugging connectors and spraying WD-40 in them" old 6v moped style... its been known to work before though!

my go to point on those systems is always the blue coolant temp sensor.

John et all.
Came home from work and started it from cold.
Ran fine, ie as usual, slightly high tick over until warmer.
Pulled off pipe to MAF and engine spluttered, revved engine and put pipe back on. Tick over settled down.
Went for a spin (euphemism for thrashing the nuts off it)and it ran fine.
Got home and left it ticking over at which point it started running rough.
Seemed like over fuelling! With funny smell from exhaust, sort of carbony but not neat fuel.

Do you now think?
Blue coolant sensor
Blocked fuel filter
MAF sensor
Lambda Sensor
Or other

Dave

hmm well a blocked fuel filter would cause it to not get enough fuel.. was it changed last service? to be fair the little nylon prefilter in the tank would catch most stuff. its quite fine.

i didnt think the 1.1 engine had a MAF (mass air flow sensor)?? unless you ment MAP (Manifold absolute pressure sensor)
if the MAP made the enigne run rough when you disconnected it then i would have thought it was running... however whenever i disconnect the one on my 1.2 engine in Fallout it causes the engine to stop dead.. (im lazy when working on the engine to rather than moving around the side of the car to turn the key, i just find another way to stop the engine.. and that works.)
maybe its not sensing right. any punto 55, 60 or 75, cinquecento 899 or 1.1 has them and they are all the same part.

if the lambda is not reading right that will cause the engine to over or under fuel. it is, its job to read the O2 levels in the exhaust to determine how well it can burn fuel.
over time these guys can get clogged up with carbon, for what it takes just change it over.

pretty much every lambda sensor is the same no matter how many wires it has. the more wires, the more "modern" it is. the old single wire ones took a while to warm up as they had no heater built in, but then they came out with heaters. Talon's lambda is 3 wire, 2 wires for the heater (white) and one wire for sensing (black). some have 4 wires, the extra 4th wire is an earth (grey)
i'd swap the sensor out for a different one being as its in a easyish to get to place. think its 19 mm. just make sure you get a sensor with the same plugs on it as yours. not sure but i think the 1.1 is a 2 plug sensor. however it could be a 4 wire single plug like the 1.2 engine.

blue coolant sensor could be reading on and off. if that reads cold, it will try to force the ECU into closed loop mode. (its like putting the choke on only also messes with ignition timing as well as fuel delivery).. again i'd replace it. for what it takes. its pretty easy to get to.
if you are quick you can change these without loosing all your coolant. just make sure your engine is cool. hot coolant on skin is not nice.


try each sensor one at a time..

im not sure of any scrap yards up in chesterfield, but if you want to come down to derby and let me have a look at the cinq i can.. plus i have fallouts boot full of spare sensors haha
and if i dont have the sensor, im pretty friendly with the guys at my local scrap yard so for small stuff most of the time they just let me have it.

Unplug the coolant temp sensor (this will throw the injection light) and run the engine, does it run noticeably rougher, seem more hesitant or choked etc?. The fact you said the light went on to start with suggests that sensor to me, it's actually the only sensor on mine that has ever threw the light at all when it failed!

If it's not different at all, then it's probably worth replacing.

BUT.... first things first, i'd pull the spark plugs out and see what's really happening, whether there's any soot build up on them etc or whether they are suffering any other weird signs. That could tell you a lot too.

Right chaps.
Have taken of air filter body, removed all spark plugs, all nice and lightly brown.
Have cleaned out mesh filter in cylinder head to air filter breather.
Have swapped blue coolant sensor, then unplugged it.
The result was a consistent rise in tickover speed.
Putting the connector back on just slowed the tickover to normal..
Took fuel pipe off and turned on ignition.
Plenty of clean fuel came through, but couldn't test pressure.
Have put in Wynns injector cleaner as well.
Ran it up to temp, no missing , over choking etc.

Took the blasted thing for a run, still seems to go well but still dies occasionally when you put your foot down. Ease off and it picks up again.

Any more ideas?
May it be the fuel pump is not putting enough fuel through at full throttle
One odd thing is it can hiccup going round ninety degree bends.

Dave

hmm that is strange.. have you noticed it do it with a full tank of fuel?

No, but going up a hill in Chesterfield I floored it.
It pulled hard in second and then died, only picking up again when I eased off the throttle.
Then on getting to the doughnut in town it died again with the engine management light on.
It restarted straight away and after 30sec it the light went out.
Weird or what.

yeah that is odd.. hmmm

im getting a fiat ECU fault reading cable through the post, if you want, i could look at it for you?

John.
Things go from bad to worse, depending on how you look at it.
The wife nearly ended up under a bus as the engine died in front of it.
It went to idle but every time she put her foot down to pull away there was no power to do so. Same thing happened all the way home

Have stripped and cleaned all electrical plugs, used Wynns, replaced fuel filter, cleaned throttle body with carb cleaner, reset ecu. Etc.

Car starts first time every time with revs at 1200 when cold, dropping to 950ish when warm.
I called at a 'specialist' who reckons the only thing it can be is the lambda sensor, and to give it a thrash. I told him it wouldn't,t get to the A38 to do so
Only problem on leaving his place it died again with same symptoms.

Came home checked everything, thrashed it hard and no cutting out

Would you replace the sensor or look elsewhere.
Dave

you tried unplugging the lambda sensor? the car will run fine without it.. it would poison the cat over time though but for testing, it wont hut it.

i still have not got my damn cable here yet.. as soon as i do i can pop up and run a diagnostic on the engine.
my money is on the MAP/vacuum sensor being at fault though.
i have spares here so i can just bring one up when i come up to do the diagnostic. you can have it for free.

found broken wire on the lambda sensor, so replaced both it and the blue coolant sensor.
Went for an 15 mile drive and thought I had cracked the fault.
Came out of Matlock UP THE HILLS to Chesterfield and car died again.
It now seems to be a fuel fault as it dies more when extra power is asked for in 4th or 5th gear going up hill.
New fuel filter going on tomorrow.
Dave

hmm damn. what colour wire was it that was snapped out of interest?
every wire can snap off BUT the black one and it will still work. the black one is the data wire. the other wires are there to run the heater and make a good ground.

i wonder if its got a manifold air leak somewhere. so me a favour and check your brake servo vacuum pipe..

other than that.. check if there's any vacuum on the fuel tank.. take the filler out and if it sucks in air, maybe that is the fault.

it could be that the injector may be blocked a little.. shine a torch into the throttle body as its running. if the fuel atomises real nice then it wont be blocked. but if the fuel just pees into the throttle it could be a blocked injector or not enough fuel pressure

John.
The broken wire was a bodge by the previous owner using a sensor without a plug, so wires were taped together.....
After I replaced it the managment light went out and. Has stayed out....
Fuel does atomise nicely, but symptoms now seem to point to fuel pump pressure or failed filter.
Strangely enough I did check the servo pipe for leaks, it is kinked but not sucking air in.
Will re investigate throttle body tomorrow after changing filter
Only other thing could be a failing ECU

Other than that Derby here I come in 200 metre bursts.
Dave

yeah indeed.. that is odd. i have got a replacement fuel pump if it turns out to be that, but they never really fail till they get really old.

sadly i dont have a spare throttle body for a 1.1 :/ though next time i am at the scrap yard i will have to grab one if it is not fixed by then.. i may take a trip down Tuesday as i need to get some parts for a friends car. im going in for quite a few bits so if i stick it in the bottom of the bag they may not be bothered to check all the stuff and give me a price for the whole lot as a bulk buy.
ahh just checked online and they dont have anything with the 1.1 engine in. they do have plenty of puntos in with the 1.2 engine but i am not sure if they use the same throttle body. ill have to check.

i think yours has the 16F ECU?
i would not mind one myself for playing with, so while i am there i may grab a punto 60 ECU with transponder chip/key and code box. if that goes on the 1.1 engine wiring loom then .. if you wanted.. i could lend you the ECU, code box and key, then you could swap them over and see if it runs good on that ECU.

we have recently got our grubby little hands on a complete dealership level ECU diagnostics computer with 2013 software which supports every car under the sun.
you can even control engine RPM, EGR, force it to do a DPF regen, recode fuel injectors and.. well everything you need to fix a modern engine.
the cool thing is that it supports ALL fiat ECUs. even the strange Bosch ECU talon is running!

i'm pretty sure that using that will tell us what is going wrong with your engine.

£1500 worth of garage diagnostics.. bought for scrap value. man i love hunting scrap yards.

Update
Loose vacuum pipes replaced, new fuel filter fitted, black crap that came out of old one was unbelievable even though fuel at throttle body was clean as a whistle.
Took car for a spin 4 miles all ok then same symptoms.
Went to weber specialist who suggested taking Petrol cap off and going round the block. Lots of pressure when we took it off so he thought this was the fault.
Without the cap on it seemed ok.
WRONG.
Filled up with petrol did 20 miles on all road conditions, fast , hills, slow, and town.
Still dies at random and engine management light comes on. Turn engine off and restart and light goes off.
Ease off the throttle and it only just keeps going, accelerate to try to pick up speed and it dies.
Am I right in thinking SPI pulses fuel, so could it be a sensor or part of the throttle body that's faulty
Help Dave

hmm the injector is fed direct from the fuel pump at about 1 to 1.5 bar. the injector only fires when the engine is on the intake cycle so it does pulse into the throttle...

now if the ecu is finding a fault then on monday when i get the cable, i will be able to come up to you and diagnose the fault... just got to hope i get it on monday.

I'm starting to lean towards an intermittently failing crank sensor or the fuel pump itself either blocking (you say the filter was gummed, well cinqs pumps have a mesh filter on them too, so could be under some situtions the gunks blocking it or the filter on the pump has collapsed) or failing.

hmm but if the pump was failing, the ECU would not pick it up.. theres no sensor on the marelli ECUs of that age dont have fuel pressure sensors.

i agree that it could be a failing crank sensor also...