Technical HELP stop and start unavailable/warning light/engine light

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Technical HELP stop and start unavailable/warning light/engine light

maybest1

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I have a fiat 500 pop 2011 model, stop and start light, warning light and EOBD injection system failure light appears when I reach 70mph. The engine light flashes and goes away but the warning light and stop/start light stays on.

However, the car runs completely fine, it has never had the feeling of a misfire, with no loss of power and no noise from the engine. It runs like a good car with no problems except these lights.

I have been to the garage and the car is saying misfire - spark plugs, however i have changed these and no change to the lights. I then changed the coil pack and wires leading up to the spark plugs and no change to the lights. I am really concerned whether it could have anything to do with the piston, especially when the car is only 6 years old and done 60,000 miles.

The garage has done a compression test on the four cylinders and the results are 1- 235, 2-150, 3-235, 4-235. is there anyone who has had similar problems with their fiat or any car?
 
Hello and welcome to the forum.

Sorry to hear you've got a problem.

The garage has done a compression test on the four cylinders and the results are 1- 235, 2-150, 3-235, 4-235.

If those figures are accurate, then you may have a serious engine problem. Low compression on a single cylinder is generally down to one of three causes:

1. Head gasket failure
2. Valve/valve seat failure
3. Piston ring failure.

I'd strongly recommend the car not be driven until this is properly diagnosed and sorted, or you risk making a bad situation worse.

The next step is to confirm the compression readings. A definitive diagnosis is going to require the engine to be dismantled and you don't want to do this if the garage just misread the compression on #2 cylinder. When the compressions are rechecked, do the test twice; squirt a little engine oil into the bores the second time around and note any difference in the results - this can help distinguish between valve problems and piston ring issues. Also pressure test the cooling system; if it won't hold pressure, it would point toward there being a head gasket problem. Note that the head gasket doesn't necessarily fail into a cooling channel and HG failure can't be ruled out even if the cooling system checks out. Check the valve clearances; this could help identify a valve fault.

Apart from HG failure due to running the car with insufficient coolant (which is quite common), the 1.2 FIRE is an extremely reliable engine and this kind of issue is almost unheard of.

What's the history of the car?
 
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I'd strongly recommend the car not be driven until this is properly diagnosed and sorted, or you risk making a bad situation worse.
Utterly agree.

One cylinder down on compression is indicative of the top end IMHO, though nothing is certain.

Head gasket or valves. JR's suggestions are spot on to test stuff out.

Get the head off and investigate. You'll need a new HG anyway, and even if the issue turns out to be the piston and/or rings, a top end inspection is the first port of call.

I'm very sorry hear of this problem, and I understand that these engines are really strong and reliable, so I sincerely hope that it's just a new gasket that's required.

Good luck, and keep us informed,
Mick.
 
Wow thank you all for the responses they are all so helpful.

The history of the car has had a service roughly every 10,000 miles with the last one being at the speedo reading 63,751 03.05.17, before that 58,330 3/5/16, from then on 53,771 21/12/15, 42674 02/05/15, 28055, 27/05/2014, 16,448 3/06/13. - In additon, the car has just passed its mot in May. Fiat 500's are suppose to be reliable cars but i am not convinced after this happening at such low mileage and to a well looked after car. (n)

I forgot to mention that the garage did an EML scan and the error codes were P0300 -ingition failures recognition, P0302 cylinder 2 ignition failure, P0303 cylinder 3 " ". They also said they believed it could be the piston cap that has blown, but i will do my own compression test with the suggestions mentioned above to see if the results have changed.

I have booked it into fiat for the 6th sep to get a second diagnosis before spending £1000 of which the garage quoted to remove the engine and see if its the piston.

I will keep you posted on my own results from the compression test and what the fiat dealership says. Thank you all for your help.
 
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I am not sure about the coolant but I am pretty sure it would be topped up when it was serviced. I have taken a photo of the oil on the dipstick which is attached below.

If it was something to do with the engine would the engine light not be constantly on? Why is it that it only comes on at 70 mph? Is there any other problems that it could be such as a sensor or a fuel injector?
 

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I have booked it into fiat for the 6th sep to get a second diagnosis before spending £1000 of which the garage quoted to remove the engine and see if its the piston.

I will keep you posted on my own results from the compression test and what the fiat dealership says. Thank you all for your help.


£1000 pounds sounds a lot for diagnostics. I'm surprised they want to remove the engine. A head removal would be the logical next step and you should not have to drop the engine for that. It will let you inspect valves, head gasket, bores and top of pistons. Even if you can't see anything you have to replace the head gasket and that may effect a cure. Get a couple of quotes for this work first.


Another useful diagnostic tool is a borescope to look in the engine via the spark plug holes. I have a little 1/2" one that plugs into a laptop USB port. Quite cheap on ebay. also for Android tablets or phones. a couple of random examples (I've not bought from these sellers)
http://www.ebay.co.uk/itm/111929569382
http://www.ebay.co.uk/itm/222531366213


These will show you gross issues like burnt valves, bad cracks in head or badly scored bores.


Robert G8RPI.
 
This post contains affiliate links which may earn a commission at no additional cost to you.
It's unrelated to this problem, but looking at the age of the car, may I ask if you know whether the timing belt and water pump has been changed or not?

If not then that is something that will need doing ASAP as it needs doing every 5 years on the 1.2 (can't remember the mileage but it's around the 60,000 mark).

Purely mentioning this seeing as your car is booked into a Fiat dealer, just wanted to be sure that you have everything all sorted in case it costs a bit(y)

And if it has been done then no worries!
 
I believe £1000 would be the cost to open up the engine and change the piston which they believe to be causing the problem. Thank you for that suggestion of the tool i will look into that when i next examine the spark plugs.

Also i think if fiat tell me the water pump needs changing then I will just do it myself thanks for the advice!!

The next step is to confirm the compression readings. A definitive diagnosis is going to require the engine to be dismantled and you don't want to do this if the garage just misread the compression on cylinder.

Just a quick update I did a compression test today and the results were different to the garage. For Cylinder 1 - 185, Cylinder 2 - 180, Cylinder 3 - 185 Cylinder 4 180. This has made me even more confused, the lights are still coming on but not affecting the drive of the car. I still have the fault codes of P0302 and P0300 suggesting a misfire.

Do you think with these readings it could still be the piston? If anyone else is experiencing anything like this please comment below. I will see what fiat come up with and update you all.
 
I believe £1000 would be the cost to open up the engine and change the piston which they believe to be causing the problem. Thank you for that suggestion of the tool i will look into that when i next examine the spark plugs.

Also i think if fiat tell me the water pump needs changing then I will just do it myself thanks for the advice!!



Just a quick update I did a compression test today and the results were different to the garage. For Cylinder 1 - 185, Cylinder 2 - 180, Cylinder 3 - 185 Cylinder 4 180. This has made me even more confused, the lights are still coming on but not affecting the drive of the car. I still have the fault codes of P0302 and P0300 suggesting a misfire.

Do you think with these readings it could still be the piston? If anyone else is experiencing anything like this please comment below. I will see what fiat come up with and update you all.

Thse results would indicate it's not a holed piston at least, that would be a permanent low compression.
Lets see what the Fiat garage says next week before we do any more speculation.

Robert G8RPI.
 
Just a quick update I did a compression test today and the results were different to the garage. For Cylinder 1 - 185, Cylinder 2 - 180, Cylinder 3 - 185 Cylinder 4 180. This has made me even more confused, the lights are still coming on but not affecting the drive of the car. I still have the fault codes of P0302 and P0300 suggesting a misfire.

Do you think with these readings it could still be the piston?

5psi difference between cylnders is normal. Also the numbers you got are more in line with what I'd expect to see than figures into the 200's. You can sometimes tell more from the way the gauge behaves as you test each cylinder in turn; those sort of differences aren't reflected in the final hard numbers.

Given that these engines almost never give hard mechanical problems (unless run short of coolant, and there's no evidence of that), I wouldn't be taking the head off just yet.

As g8rpi says, let's see what the Fiat dealer comes up with - but I'd by wary of accepting their diagnosis as gospel unless it clearly makes sense.
 
5psi difference between cylnders is normal. Also the numbers you got are more in line with what i'd expect to see than figures into the 200's. You can sometimes tell more from the way the gauge behaves as you test each cylinder in turn; those sort of differences aren't reflected in the final hard numbers.

Given that these engines almost never give hard mechanical problems (unless run short of coolant, and there's no evidence of that), i wouldn't be taking the head off just yet.

As g8rpi says, let's see what the fiat dealer comes up with - but i'd by wary of accepting their diagnosis as gospel unless it clearly makes sense.
+1
 
Hello everyone,

So I have been to the fiat garage and good news! They carried out an investigation into the EML and found codes for cylinder 2 and 3 misfire. They carried out an investigation of the engine compondents and were unable to fault.

They looked into the ECU software on the car which hadn't been updated. They carried out this update and new software avaliable for the ECU. They then test drove the car for 31 miles and no lights (stop/start, warning light and engine light) !!! The diagnostic test cost £114 which has saved me £1000 from the other garage who wanted to look into the piston and dismantle the engine. Always get a second opinion on these things.

I have driven the car at 70mph, on a few long journeys and I haven't had lights since!

Thank you all for your help (y)
 
Fiat inspected all the compondents to spark plugs/cause of misfire and said that it isn't an issue with the engine. They didn't mention to me the results of their compression test but when I conducted that test myself the results were normal (I checked them over 3/4 times). Like G8rpi said if it was an issue with the piston it would lead to a permanent low compression.

So I don't know how the garage could of come to that estimation! I believe they were simply looking at alternative options of what it could be.
 
.....They looked into the ECU software on the car which hadn't been updated. They carried out this update and new software avaliable for the ECU. They then test drove the car for 31 miles and no lights (stop/start, warning light and engine light) !!! The diagnostic test cost £114 which has saved me £1000 from the other garage who wanted to look into the piston and dismantle the engine. Always get a second opinion on these things.......

Well I'm very chuffed for you! (y)

Many won't agree, but I'm happy to extol the virtues of dealership diagnostics when problems appear to persist and seemingly endless looking and prodding fails to sort the issues. I've known owners prat around for weeks or months, doggedly refusing to nip to the Fiat dealership and fork out for a diagnostic test/update and yet will spend quite literally hundreds of £££'s getting other people who've no idea what they're doing, trying to diagnose a problem.

When we had our 1.2 POP, I received a card from our not quite so local Fiat dealer, offering a free no strings attached diagnostic test. I drove the 25 miles there, walked into town and returned an hour later for them to tell me they'd flashed the ECU to the latest update and furthermore, 'discovered' that the electric steering control unit was apparently 'faulty'. They couldn't benefit from me personally for fixing it as the car was still under Fiat warranty.

The point I'm trying to get across is, if you are a new or recent owner to a 500 and it hasn't seen the rump end of a dealership for 3 or 4 years, it might be worth just forking out for diagnostic test if you intend keeping the car for a while. There's often a reason why manufacturers issue ECU software updates, usually to solve problems reported by owners. A couple of years ago, I took my Saab 9-3 to a former Saab garage who at my request, carried out a diagnostic test and my vehicle ECU received a whole raft of updates. I have to admit, it ran better afterward! Cost me £100. Sadly though, lots of cars once out of warranty, never see a dealership again, understandable though considering how much some of them charge.
 
Mine does similar but only after staying in 5th at 70 for a while - happens so rarely. Might need to run mine through to a dealership sometime or get a diagnostics done on it.

Thanks for posting this and keeping us all updated with your progress!
 
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