Hi Everyone

I have a love/hate relationship with a little Fiat 500 twinair which I would love more and hate less if it stopped being such a nightmare to start..

It's a late 2011 model with 60k miles which i've had for 2 years now, i do approximately 18-20k miles a year, mostly motorway. I must say, it's been a pleasure to drive for most of my ownership, however, in November 2017 I started to have issues when trying to start the car on a cold morning, it sounded like it was firing on one cylinder and took ages turning the key to get it fired up, after running for a few minutes the car behaves normally..

I took it down to a mechanic friend who put his diagnostics on it and it came up with a cylinder 2 miss fire, having done a little research this pointed to a possible faulty lambda switch so £150 later an NGK lambda switch was fitted and it seemed to behave ok for a few week or so, all was good.. Then the dreaded startup problem came back.

Question is, has anyone experienced this problem before? does anyone know what it might be?

Any help would be much appreciated.

Thanks, Rob

Forgot to say, it's only ever been serviced by Fiat Ancaster, It did feel a little sluggish after the last service but this may just be me expecting too much from my little Fiat.

Hello and wecome to the forum.

I wouldn't expect a faulty lambda sensor to affect startup when cold, as the fuel control system should be running open loop at this point; it might affect hot start capability.

It's not easy to diagnose a fault sitting in front of a keyboard, but this sounds to me like it's an ignition problem. My first suspect would be the spark plugs, closely followed by the coil packs.

Coil packs are a known issue with earlier TA's and there have been both recalls and warranty replacements on some cars from that period; it could be worth checking if there's anything outstanding on yours.

Robt1970 said:

so £150 later an NGK lambda switch was fitted

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£150 for a TA lambda sensor seems a little excessive; it's only a few minutes work and the part can be bought for half that.

Thank you for replying to my post, the spark plugs were replaced on the last service (sept 2017) I will get these checked just in case. I'm not sure about the coil packs, they certainly weren't on the invoice for the last service. The thing is, when you let it idle for a minute or two it jumps around like crazy and sounds rough, certainly not drivable. If you turn the engine off then on again, its absolutely fine and runs as normal. I had a porsche 997 which had a number of split coil packs and this had a similar rough idle but it was constant, you couldn't get it to run smooth by restarting car like i can with my Fiat 500.
It certainly does look like an electrical fault, whether its ignition or ECU, Im not sure, but it would be nice to hear if anyone else has experienced the same fault with a successful fix..

As for changing over the Lambda, it did look like a bit of a job, took about 1 hour or so, engine cover, battery and tray out, the switch holder was under the battery tray so not possible to unplug easily without stripping a bit out, I guess being in London, prices are a little higher but i needed a quick fix so would have paid regardless..

I just had my twinair actuator replaced, lets hope its not that!!
Read my thread further down "serviced my twinair plus yesterday"

If it turns out to be coil packs I have a couple with about 30k on. I replaced mine when I didnt need to. You can have them for the cost of postage to try them out if you like? Save a few quid.

Ps Fiat oil changes aren't frequent enough on the twinair engine.

Forgot to mention the clutch linkage that can fracture (mine did) and caused the same symptoms but I don't imagine that would throw up a mis fire reading?

I wonder did they use the correct oil in the last service? If the wrong oil is used they can definitely be rough at idle when cold. It’s a specific oil and not at all unusual for the wrong spec to be used

Assuming the oil is correct spec and level(remember the oil level needs to be checked immediately after turning the engine off), then I suspect it's the UniAir unit. Could be as simple as a blocked UniAir filter as these are never cleaned by anyone

UFI said:

Assuming the oil is correct spec and level(remember the oil level needs to be checked immediately after turning the engine off), then I suspect it's the UniAir unit. Could be as simple as a blocked UniAir filter as these are never cleaned by anyone

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Thats where Im going wrong, I normally wait until the oil drains to the sump before checking the level

Surely as long as I put the correct amount of oil in at oil change and it shows on the dipstick then that is the level I look for when topping up after the oil drains to the sump?

If the car is parked too long oil will continue draining from the UniAir unit.

The best time to check the engine oil level is about five minutes after a fully warmed engine is shut off. Do not check oil level before starting the engine after it has sat overnight. Checking engine oil level when the engine is cold will give you an incorrect reading.

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UFI, there has been some recent discussion on the 500X forum about the Multiair filter blocking in the 1.4 MA engine. In that case, it is fairly accessible, and not an expensive part. Do you have any details of buying/fitting the equivalent part in the TA? It could well be the problem, and could be a simple fix.

TrevC said:

UFI, there has been some recent discussion on the 500X forum about the Multiair filter blocking in the 1.4 MA engine. In that case, it is fairly accessible, and not an expensive part. Do you have any details of buying/fitting the equivalent part in the TA? It could well be the problem, and could be a simple fix.

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I don’t think you replace the filter, you just remove,clean and replace. There’s a thread in the Panda section

Just had the Plugs and coil packs checked, all seem to be in good order, thanks for the offer Bookish..
I tried to start it today at 3 degrees and it didnt like it at all, went into limp mode with the engine light on, after letting it run for a few minutes I turned it off then tried after 10 seconds or so and it was perfect, smooth idle with full power..
BOOKISH, Did yours have an actuator problem with the same symptoms as mine ?

I was wondering if anyone knows where the Uni-Air unit is on the car and possibly where the filter might be placed? I'm hoping it might be a dirty or blocked filter, hoping its not the actuator!!

I had it serviced by Fiat Ancaster in September 2017, they have a service menu so i thought i should go for the £299 full service, plugs, oil, filter and all the other bits they are supposed to check over, I wonder if that sluggish performance when i got it back was anything to do with the problem? it did seem to start ok in the mornings though.

Twinair valve actuator oil filter
https://www.fiatforum.com/showthread.php?t=454649

I really would investigate your oil though

Thanks Mercky, I'm assuming Fiat used the correct oil in the service but just in case, what oil is recommended for a twin air?

Selenia K c3 grade, mine had those symptoms yes. But there is so many variables in what could be causing it. As I've mentioned previously my clutch linkage up by the peddle fractured and caused lumpy idle and irratic driving but not sure this would be running only one cylinder though. My initial thoughts when i got the symptoms again were like you.....coil packs, spark plugs, new oil and filter and also checking my peddle linkage again. It's only when I got a specialist fiat/alfa garage to do a diagnostic it threw up the actuator fault.

https://photos.app.goo.gl/l8EgusjfefIBC18w1

Have a look though my photos to see the small filter/strainer on top of the engine under the air box. Mine turned out to be clean.
You'll need a narrow 15mm socket (got mine from the bike section in halfords)