Technical Odd Twinair error.. Investigations

[Tropicalmike]

Have you actually had MES on when the problem happens to see the live temperature? Swapping the solenoid connectors and doing the "ticking" test only showed me anything on a stone cold engine. The engine sump is alloy with fins so it must also contribute to oil cooling . TBH I havn't thought /looked at the oil cooler below the main oil filter but presume it has engine cooling water through it. So an issue with the thermostat could be a factor.

 

[varesecrazy]

No, not tested 'hot",

But today in Stone cold temps

I tried to activate both injectors.. All good

Checked temps.. All look sensible

Warmed motor from cold, again temps climbed in a controlled manner

Info : at point of failure while driving, stored errors were at a temp of 85'c, which sounds normal


I will plug into another TA this week to see if it "looks" any different

Maybe the different ECU's will display differently though..

 

[The Panda Nut]

I am sorry have no experience to base comment on. I would have the sump off and check the oil pick up. I seem to recall a few failures. Based only on daffo our old 169, I would also change plugs. What does mes say about injectors. He had misfire codes and did overheat. Laughably plugs seemed to fix it. Check you dont have a loose plug? I might also try another coil try each one in turn?

 

[Vic20]

What oil is in the engine? Our twinair would only run properly (including passing MOT emissions) if Selenia / Petronas Oil was used. It's complex temperature / viscosity profiles are what the Uniair was designed to accommodate.

Remeber to do a Uniair reset in MES after replacing the oil too!

 

[varesecrazy]

What oil is in the engine? Our twinair would only run properly (including passing MOT emissions) if Selenia / Petronas Oil was used. It's complex temperature / viscosity profiles are what the Uniair was designed to accommodate.

Remeber to do a Uniair reset in MES after replacing the oil too!

Strange you say that..

My 2 TA"s are the lowest emissions of any car I have owned
(Obviously being ZERO VED is a clue.. as a reference)


Been on 5 different brands of oil with no obvious change

Just realised.. This is MY Panda thread..

It has run the same..

Good AND bad

On TOTAL, Selenia and now Millers

 

[Vic20]

Yes, ours was too, HC's and CO near zero, but without Selenia oil it would get a high Lambda figure, sometimes on the edge of the Fail point. A sign of too much oxygen in the exhaust gases. All other possible causes (manifold / exhaust leak) were eliminated. Basically this was due to the inlet valves not closing quickly enough due to the different oil letting in a little more air than metered.

Tolerances in the uniair are incredibly tight, obviously tighter in some units more than others!

 

[The Panda Nut]

I too stick with Petronas for these reasons. It should be fine with a same spec oil, but additives are now so important, or absence of them. Im suspicious that oil also varies from one batch to another so you may just have filled with a batch thats just too far off the spec. Probably more than fine in anything else. I wish we had all the information to make an informed decision as I hate Petronas in general.

 

[Tropicalmike]

No, not tested 'hot",

But today in Stone cold temps

I tried to activate both injectors.. All good

Checked temps.. All look sensible

Warmed motor from cold, again temps climbed in a controlled manner
View attachment 445679
Info : at point of failure while driving, stored errors were at a temp of 85'c, which sounds normal


I will plug into another TA this week to see if it "looks" any different

Maybe the different ECU's will display differently though..

Just read through the whole thread again. My 500 TA has Uniair oil temperature at 84 deg.C when up to temp. May be it was it 85 or 86 it was 5 mins after I stopped when I plugged MES in.

I assume you meant you tested the uniair solenoids not the injectors on a cold engine .

But thinking about your symptoms that it occurs at 90 mins driving only in summer time ( when ambient temperatures are higher ) and that the engine runs a bit rough for 300 metres or so on starting . The Uniair is designed to run on 0W30 oil ( ACEA C2 Fiat spec 9.55535 GS1 , Which your Miller's oil is ) in a range of temperatures from cold to hot with corresponding viscosity from thick to thin . The ECU only knows the Uniair oil temp and how many hours/miles run the oil is from the last oil change reset and on that information it controls the actuator solenoids based on the viscosity it thinks it is . Also the throttle demand and other engine sensors including the Lambdas . But there will be some minute wear in the Uniair actuator on this engine on it's mileage . I know the ECU learns how the whole combustion performs but I don't think it has some adjustment on assumed wear with age, So at 90 mins running in summer the viscosity is just on the cusp of being too low that Uniair action is effected giving the misfire ( or the oil viscosity is different from what the ECU thinks it is ) and also oil pressure just on the verge of being too low ( hence the warning light that one time ) This says viscosity too low .
Did you do the oil change reset in MES at last oil change ? If not done the ECU thinks the oil deteriorates further probably increasing it's viscosity (from contaminants ) thinking the oil is thicker than it really is. Worth doing this now if not already done or at next change,
So........ how can you get the oil viscosity a bit higher when the engine is hot . First thing is eliminate any chance of a slight oil overheating issue .. but second idea is a bit radical . but how about drain off about 1 litre of 0W30 and add in a fully synthetic oil of the same make but 0W40 or 5W40 . This will mean the oil will be a bit thicker at the higher temperature. Might be worth an experiment, but it would be a "fudge " masking the real issue that could be the wear in the Uniair actuator . But it would prove that it is the viscosity that causes it .

I am sceptical that using only Selenia oil is the at the crux of all these issues. Many of us have TA engines running fine on non Selenia oil. Of course even Selenia Oil could have a bad batch mix too . It is the oil viscosity that is the key factor to the hydraulic action in the uniair actuator. The chemistry in the synthetic oils is complex and one of the additives is to maintain viscosity at higher temperatures and another to combat contamination from combustion products and acidity level and another to aid how the oil clings to metal surfaces of cylinder walls and bearings especially with turbo chargers . The C2 is to do with the Euro 6 compliance I believe. I think if there was a special oil additive just for the uniair action it would be mentioned somewhere in one of the technical articles on them. Using 0W30 C2 Fiat 9,55535 GS1 is important for the whole engine . What I would love to see is the graph in the ECU programme on how it modifies the actuator signal based on oil temperature and oil age. but for sure it is based on the engine having the correct oil and how it should change as it ages.

Apologies for prattling on here this evening and teaching anyone to suck eggs . Interesting and frustrating with these TA engines !!!

 

[varesecrazy]

Thanks for that,
a few very relevant things there I want to work through

 

[jrkitching]

If not done the ECU thinks the oil deteriorates further probably increasing it's viscosity

With age, a good quality oil will first thin slightly, then thicken slightly (though if changed at the recommended interval and topped up when necessary the latter should not happen).

A low quality oil (which you shouldn't be using in a TA) will likely first thin out of grade and then thicken a lot.

I would be hugely surprised if the ECU makes any compensation for oil viscosity based on age; I've never seen this documented anywhere.

 

[The Panda Nut]

I interpreted the reason for the reset process to be exactly for this reason. I thought the ecu does account for degradation over time, miles or both of the oil and the reset is to inform it at a given point its got new oil again. It does magnify the fear this system creates in me if that amount of change has a sustantial impact. Even more it says stick with the specific oil around which the system is designed. When Petronas stop doing that oil we are all stuffed. I am sure the uni air system is not of Fiats design either. This explains why they dont know how it works, how to fix it, or what is wrong when it doesnt perform right.....
I have also noted tge car does not start cleanly with some oil changes, and now thing tge garage went through a phase of using Castrol. I took tge last car back after service becauae of this. They shrugged. Stop startcrestarts are clean and instant on tge right oil, but sometimes awkward with, I susoect, a different oil.

 

[Twotone2]

I'm just about to do the first oil change on our Panda 4x4 TA (2023) and I've read various things about the oil reset using mes which I have but there's nothing actually definitive describing how it's done or should be done, one of the guys on here said it was a complete waste of time ie revving the engine up to 6000 revs for so many seconds for so many times and the OP said he's never done an oil reset on any of his cars BTW.

Anyone have a link to an actual oil reset guide using mes or should I just change the oil and reset the service time to zero?

The car's only done just under 5k miles and is just over a year old but we've only had since last July and it sat in the dealership for about two months there was only about 100miles on the clock when we picked it up.

Just had a quick read through mes user guide, page 45 explain's how to do a 'service interval reset' which seems easy enough however there's no mention of carrying out an oil reset for a TA there is this below though which doesn't apply to my car.

"Please note that for vehicles equipped with DPF you also need to reset the Oil Change indicator in engine control module. You have to connect to the engine control module, then go to Adjustments and execute “Oil Change” procedure."

 

[Vic20]

Uniair reset is discussed here https://www.fiatforum.com/threads/slight-lumpiness-briefly-old-cold-start-twinair.508033/
It's in the same actions area on MES, which in itself details how to carry it out.

 

[Twotone2]

Uniair reset is discussed here https://www.fiatforum.com/threads/slight-lumpiness-briefly-old-cold-start-twinair.508033/
It's in the same actions area on MES, which in itself details how to carry it out.

Had a look on mes simulation mode and notice that there's a service interval reset option available and also an oil change option available (below) depending on the engine version.

So does this mean after an oil change, oil filter change and air filter change then the service interval reset procedure has to be carried out plus the oil change procedure for the UniAire module?

Thanks

Tony

 

[Tropicalmike]

I have done both on my 500 TA
So I would say yes

 

[varesecrazy]

Thanks for keeping this thread rolling

Correct.. I have not reset Any parameters

However the garages I"ve selected = Italian Specialists (using Selenia)

Will have used Examiner to do the resets

One car runs great, the other has its issues

And the problematic one has had a specialist service with no change to running

 

[The Panda Nut]

One is the service indicator - cars computer. Mine seems to be haywire. Garage did it. It then said next service 365 days 9miles. After 3 goes set the interval to 15540km (I think) and car said 9000 miles to service! The other informs ecu its running new oil and resets the uniaair operating parameters in the ecu. This makes sure valve timing is reset and correct for new rather than degraded oil.

 

[jrkitching]

Getting to the root cause of TA running issues is still frustratingly confusing; I don't think the forum collective has any clear cut answers yet.

The ultra cautious will probably just steer clear of buying one, but we ought to be able to do better than that.

As I see it, the possible causes to the commonly reported rough running issue are as follows:

1. Oil related issues, either the wrong grade, an unsuitable brand, dirty, old, or out of spec oil, clogged uniair oil filter. There have been a number of posts where poor running has been resolved after an oil change, and a number of other posts where poor running has started after an oil change. I'd say oil is definitely one of the potential factors to consider.

2. Software issues, perhaps resulting from a reset procedure not having been carried out or having been carried out incorrectly. There's been some debate over whether this is necessary and what it actually does; right now, I'd say the link is unproven. I don't buy into the idea that the ECU adapts according to the age of the oil; any change in oil parameters as the oil ages is completely unpredictable.

3. Mechanical faults with the uniair module (basically excessive wear); well documented in Mark Stammers excellent case study. Some cars have had rough running issues disappear after repacing the uniair module, but I'm not aware of any easy way of assessing its condition and replacement on a hunch is an expensive gamble. Most garages won't have access to the diagnostic kit Mark Stammers used in his case study. My take is that the modules definitely wear, probably to the point where they will need replacing before the core engine wears out, and that some, but not necessarily all of the issues reported are basically the result of this module being worn excessively. Right now, replacement seems to be the only option in such cases; I'm not aware of anyone offering a repair service for the uniair module on the TA (but it could happen in the future). It would seem reasonable to me that a module that has worn, but not failed outright, might be more chossy in regard to the oil than one in good order, and more likely to give intermittent faults.

4. Mechanical fault elsewhere in the engine, leading to low oil pressure in certain situations, loss of compression not related to the valvetrain, worn plugs, etc. I'd say this is possible, probably not the most likely cause, but definitely needs ruling out before spending £1000-£1500 replacing the uniair module.

 

[The Panda Nut]

If a reset has been done and the oil not changed it is also likely to throw a wobbler. Tyese things run Very wet and produce huge amounts of mayo. I dont like this and am certain the uniair wont either. Its the big reason I changed my 17 car after just 18 months. I have enquired of many dealers they all confirm TAs are the same. MotorVogue in Kings Lynn flushed PTs engine at 2 years. It didnt seem to harm it. I would possibly drain, flush and fill with the right oil the do the oil change reset. I believe this will eliminate oil from the picture. Keep what you drain out, and use it again if it makes no difference. I would find and change the temperature sensor. Suspect bad contacts? Change thermostat, then look at the coils. MES will likely show a fault.
There is still a case of fuel, spark compression it will run but the valve opening and timing are also electr hydraulically controlled so Uniair must be a prime suspect. Why not try and find Mark Stammers and ask him for help. I know I would try that. Live data from MES is also a must do. Im happy to compare data from mine if it would be helpful or even come across and do matching live data to compare. We all need to understand this more.
Have you had a word with Millers if you use their oil?

 

[jrkitching]

Why not try and find Mark Stammers and ask him for help

I think this is an excellent idea.

Live data from MES is also a must do

If we could find some way of correlating live MES data with known faults, and also get a baseline of what a car in good order should look like, this could help a lot.