Technical Yet another TwinAir misfire right after an oil change.

[Louie Bee]

The Elearn says: " Oil temperature NTC sensor connector" Negative Temperature Coefficient Thermistor right on the TA module, looks like it measures the oil temperature inside the TA

Sorry @Zardo I posted the reply to Mike before I noticed you had confirmed Elearn sas there is just 1 Oil temprature sensor as I'm a bit slow. Have seen it is K029 and appears to be in the exact location where the UniAir connects to the engine loom, but missed where it says it is type NTC.

 

[Zardo]

Sorry @Zardo I posted the reply to Mike before I noticed you had confirmed Elearn sas there is just 1 Oil temprature sensor as I'm a bit slow. Have seen it is K029 and appears to be in the exact location where the UniAir connects to the engine loom, but missed where it says it is type NTC.

No worries. See page 260 in the pdf file https://www.schaeffler.com/remoteme...loads_11/Schaeffler_Kolloquium_2010_18_en.pdf

It is necessary to monitor the oil viscosity, particularly during cold starts and the subsequent rise in internal temperature of the system. In this context, and as the only additional sensor for this system, the temperature sensor (Figure 13) is an important component. The sensor measures the oil temperature in realtime and supplies an important input for the control unit for determining the oil viscosity. The temperature measurement sensor already present on the engine for measuring cooling water and engine oil is not fast enough. The sensor with a NTC element (negative temperature coefficient) is specially calibrated for use at low temperatures (highest precision at 0 °C) and has a response time (τ90 in water) of a maximum of 1.4 seconds.

 

[Louie Bee]

No worries. See page 260 in the pdf file https://www.schaeffler.com/remoteme...loads_11/Schaeffler_Kolloquium_2010_18_en.pdf

Thanks again. I think I read that too as panda nut had uploaded it, but I don't know who found it first.

I wasn't sure if 'The temperature measurement sensor already present on the engine...' was refering to existing water and Oil temprature sensors both elsewhere on the engine. The Oil and Water sensors are often (for off highway) exactley the same part inserted to coolant or oil as they just sense the temprature of liquid and don't care if it's oil or water so long as any o-ring can withstand both.

 

[Zardo]

Thanks again. I think I read that too as panda nut had uploaded it, but I don't know who found it first.

Actually it's a different document with mostly similar content.

Looks like there is some "fresh" oil flow to the high pressure chamber but I can't really figure it out if this flow only occurs when decelerating. It still don't think so. The high pressure chamber is closest to the valve and I would presume the oil in it will reach the highest temperatures. So I wonder what temperatures are actually reached there (the design limit is +150 °C) and if the oil is refreshed often enough with colder oil from the engine's oil pump when motoring on the highway under full load. It doesn't make sense to only "change" this oil in the high pressure chamber when the engine isn't producing any power.

 

[Tropicalmike]

Might be worth trying to measure the resistance of the two Uniair solenoids based on the DTC code you have .
The voltage and current in the solenoid are variable as it is the essence of how the uniair control works . If the solenoid is a bit sticky when cold with new oil in it may be trying to drive a higher current to get the solenoid to where required and that is what triggers the fault code.
The fact that it is OK when warmed up probably means not the actual coils are faulty. Just a thought.

 

[Louie Bee]

Not sure a coil would do anything apart from short or open circuit, but no harm measuring resistance. Maybe the moving part has warped due to getting too hot creating extra friction but would that get worse when warmed.

My feeling is dirt build up preventing movement, but I have seen another actuator stick due to getting too dry inside. My punto MJ egr value solenoid. I fixed that by just removing the electrical side (3 screws) and lubricating the shaft with moly grease after teasing it out with a magnet. No need to drain the coolant and remove the mechanical side. But that's on the cooler hot side so much harsher conditions compared to the uniair solenoid.

I've recorded each first startup of the day before and after adding the MecaTec and the missfire duration seems to be getting shorter.

 

[Louie Bee]

Actually it's a different document with mostly similar content.

Looks like there is some "fresh" oil flow to the high pressure chamber but I can't really figure it out if this flow only occurs when decelerating. It still don't think so. The high pressure chamber is closest to the valve and I would presume the oil in it will reach the highest temperatures. So I wonder what temperatures are actually reached there (the design limit is +150 °C) and if the oil is refreshed often enough with colder oil from the engine's oil pump when motoring on the highway under full load. It doesn't make sense to only "change" this oil in the high pressure chamber when the engine isn't producing any power.

Don't forget the top of the valves would be covered above the stem seals with fresh engine oil separate to the internal uniair oil. That would be the cooling path and lubricant for inlet, exhaust valves and camshaft. The uniair may not need additional cooling or maybe some oil constantly flows through the chamber before the first check valve, which could function as cooling separate to the post valve oil mass.

Inside the uniair oil it expands with heat and when cools is back filled with fresh oil. Perhaps speeding up and slowing down makes the oil heat and cool enough to make it circulate and let the cleaner into inner bits.

 

[Tropicalmike]

At the end of the day guys you can't do/change anything inside the uniair other than there may be a bit of crud that the additive might shift.

As it is raining here today, no gardening so I have done the test on the old oil temp sensor I have in my garage.
It is part no. 55250135 written on it.
In iced water about 1-2 degrees C
It read about 29 K ohms
In Ambient temp at 15.6 degrees C it read 14.46 K ohms.
In boiling water it read 0.881 K ohms.

I don't think NTC thermistors are completely linear if you want to plot it. But the ECU software probably allows for that.

Unless it is a dodgy connection or wiring to the temp probe I think the thermistor will be good or not. It seems unlikely that it would just give a wrong reading when engine is cold but who knows.

 

[Louie Bee]

Brilliant thanks. What kind of seal was used on the oil temperature sensor please? Wondering if remove it to test if it needs a new o-ring or copper washer.

Thinking of also removing the strainer & sucking out any oil below. Is there a pathway between under the strainer & the oil temperature sensor port?.

I now suspect the strainer is also a check valve as it has a ball bearing or something that rattles around after cleaning it... As well as being a banjo bolt with strainer. I'm thinking it's the check valve item 3 in the block diagram.

 

[Louie Bee]

OK I got about 10ml of oil from under the strainer - 15ml if I’m lucky. I added fresh oil, stirred it up a bit with the end of the pipe, and removed it. dis that a couple of times until it came out clean. I also measured the resistance of the oil temp sensor

Uniair top cover temp around 70 degrees c - 1.667K ohm
Uniair top cover temp around 52 degrees c - 2.626K ohm

So the numbers sit between @Tropicalmike scores and going the right way as it cools.

I might have forgotten to re-connect the oil temp sensor and scored another error code of P0195-15 - well it knows if open or short so maybe no need to do it again at cold.

But it's reading Oil temp as 104 degrees with no oil temp sensor attached?

Also I'm seeing no P1062-71 in the log which I believe I last reset Wednesday evening right after adding the first product (dare I say). I'm not claiming any sort of end yet. I couldn't decide on cleaning the oil under the strainer as it's skewed the product results a little. I decided it needs every bit of help I can give.

 

[Tropicalmike]

It was a captive aluminium washer on my temp probe, so a copper one should be OK too
I think that sprung ball bearing on the top of the strainer filter is just there for hand priming with oil when new or if removed and a refill required.
I think the supply oil into the strainer filter enters in centre bottom and exits into the uniair via the 4 ports on the side after passing the strainer mesh
The oil feed up from the cylinder head enters into the Uniair via another sprung ball bearing non-return valve in the underside of the uniair then goes straight to the strainer, I believe this NR valve is to keep the oil in the Uniair when stopped .

 

[Louie Bee]

Thanks again, really good to know.

 

[Peter Pick-Up]

Not a fan of additives at all.
Just use good oil, is it for me, Petronas Syntium 7000E 0W30 C2 ( Same as Selenia made by Petronas !!) and a Bosch oilfilter, change at every 10.000KM's (=about 6000mls).
As the Syntium is harder to find these days, next change will be Castrol Magnatec 0W30 C2.
Always keep the level at "max", engine needs 1/2 L in between 10.000km intervals.
One more thing about rough idling and misfire after a cold start, I changed the original two coilpacks for new Bosch coilpacks, and use the correct NGK sparkplugs, change every 30.000km's, engine runs fine, cold and hot.
I also took the oilstrainer out once, it was spotless clean after 60.000km's, so no need to take it out again.
2018 Panda Twinair, 80HP

 

[Louie Bee]

Just watch the Bosch filters as they have different designs. I've just returned one to Halfords with a made in Poland label. Same part numbers the one I removed before these troubles started but not material on the top side, just groves. Napa filter was the same, UFI and Mann still have the material top side so bit hit and miss with Bosch F026407159. I think they put the material on for good reason

I've had a Mann filter in and next oil change in a few days time will be UFI.

 

[Louie Bee]

Not to mention the Euro 5 TA is 5W40 c3 spec. Euro 6 is the thinner spec

 

[Peter Pick-Up]

Just watch the Bosch filters as they have different designs. I've just returned one to Halfords with a made in Poland label. Same part numbers the one I removed before these troubles started but not material on the top side, just groves. Napa filter was the same, UFI and Mann still have the material top side so bit hit and miss with Bosch F026407159. I think they put the material on for good reason

I've had a Mann filter in and next oil change in a few days time will be UFI.

Pictures..??

 

[Peter Pick-Up]

Just watch the Bosch filters as they have different designs. I've just returned one to Halfords with a made in Poland label. Same part numbers the one I removed before these troubles started but not material on the top side, just groves. Napa filter was the same, UFI and Mann still have the material top side so bit hit and miss with Bosch F026407159. I think they put the material on for good reason

I've had a Mann filter in and next oil change in a few days time will be UFI.

What do you mean with "material" on top, I use the Bosch made in Poland filter without problems for some years now...

 

[Louie Bee]

Damit I didn't take a picture of the bosch one before I returned it. I have the original Bosch, Napa and UFI filters ( used) at home and should have a new UFI filter later today. Not sure when I'll do the next step of the Dupag process. I've done 200 miles now with the first product in. It's raining today so don't fancy an outdoor oil change

 

[Peter Pick-Up]

The grooves on top of the Bosch filter will fill with oil and seal good enough, I have a cheap filter (Blue Print) laying around with some soft material on top, without grooves, if that's what you mean...??

 

[Louie Bee]

Yes that's what I mean. The Bosch filter used to have the material. Here is the UFI filter with flat top & material. Not sure how having dipped groves makes a seal as they are lower than the mating surface. Wouldn't they be a path for dirt too pass through?