Regen Right After Start?

[Pilot91]

Hello,

My car seems to start running hot within a few minutes of starting it, with cooling fans on full blast.
I have a checked the temps with OBDII and app

After a 9 minutes drive, I had:
Coolant: 194F
Cat B1S1: 1,000F+
Cat B1S2: 1,000F+
EGTB1S1: 700-800F
EGTB1S2: 600-700F
EGTB1S3: 1,000F+
EGTB1S4: 900-1,000F

This has been going on for a few days now, I had a checked a few days ago and the Cat B1S1 was just over 1,400F

Anyone have any ideas?

Possibly unrelated, smell of burning oil in the cabin and outside, but no smoke.
Just replaced the old cabin air filter, had some oil in it as well.

Thank you

 

[super1]

Hello,

My car seems to start running hot within a few minutes of starting it, with cooling fans on full blast.
I have a checked the temps with OBDII and app

After a 9 minutes drive, I had:
Coolant: 194F
Cat B1S1: 1,000F+
Cat B1S2: 1,000F+
EGTB1S1: 700-800F
EGTB1S2: 600-700F
EGTB1S3: 1,000F+
EGTB1S4: 900-1,000F

This has been going on for a few days now, I had a checked a few days ago and the Cat B1S1 was just over 1,400F

Anyone have any ideas?

Possibly unrelated, smell of burning oil in the cabin and outside, but no smoke.
Just replaced the old cabin air filter, had some oil in it as well.

Thank you

If you shut off the car before it finishes a regen on your next start up, it will regen process over again
Any check engine lights on?

 

[Rx7145]

I don’t think the regen will start until the engine is at full operating temperature.

 

[Pilot91]

If you shut off the car before it finishes a regen on your next start up, it will regen process over again
Any check engine lights on?

No check engine lights are on, I normally try not to interrupt a regen, but I don't think this is a regen as the idle RPM did not increase, and the MPG was not dropping.

I don’t think the regen will start until the engine is at full operating temperature.

I had checked temps earlier on my first drive of the day, and within 4 minutes of car being started, fans were already going to cool the car

 

[Rx7145]

I know from experience that fan controllers can be flaky. I would go off of actual engine temperature as reported by the ECU.

 

[ZippyNH]

Oil in a cabin filter?
Is the engine rpm slightly elevated indicating that a Regen is actually getting called for vs just a leaky injector spraying extra fuel that's then not getting burned in the engine and is then burning further down past the engine?!

I would suggest that you check your oil level ASAP and monitor it closely to see if the oil level is going up.... maybe even grab a sample and check for oil dilution since oil and fuel is a terrible lubricant....and unlike gasoline , diesel isn't easy to identify by smell.

 

[Pilot91]

Oil in a cabin filter?
Is the engine rpm slightly elevated indicating that a Regen is actually getting called for vs just a leaky injector spraying extra fuel that's then not getting burned in the engine and is then burning further down past the engine?!

I would suggest that you check your oil level ASAP and monitor it closely to see if the oil level is going up.... maybe even grab a sample and check for oil dilution since oil and fuel is a terrible lubricant....and unlike gasoline , diesel isn't easy to identify by smell.

Engine RPM is not slightly elevated like it would be during a regen, holds at the normal ~800 RPM
Oil was not low when I checked the other day. It does burn oil, but falls above the limits for VW. I need to add a qt. every 1800-2200 miles

 

[Zakh55]

A regen is just a fuel dump for the CBEA and CJAA. You have no active trouble codes and report aux fans active and abnormally high temperatures across multiple sensors.

Have you checked your fuel rail pressure in Vag?

I am not sure what the pressure specs are during a regen, but I would look at the injectors and HPFP first.

It may be that the car doesn't register changes that happen during a DPF regen as problematic, like the fuel supply, because it's normal during regeneration, and the parameters aren't associated with any codes despite being abnormal during regular operation outside of regen. Your engine coolant temperature sensors are reading normal. 194F is normal.

I don't have the full manual for testing the fuel system. On a primer test, the HPFP ranges from .5 to 3.5 BAR, after the pump runs for 30 seconds--- electric only, without the car running. The fuel rail pressure should be approximately 40 BAR at idle.

Look up the N290 fuel metering valve as well.

 

[Pilot91]

A regen is just a fuel dump for the CBEA and CJAA. You have no active trouble codes and report aux fans active and abnormally high temperatures across multiple sensors.

Have you checked your fuel rail pressure in Vag?

I am not sure what the pressure specs are during a regen, but I would look at the injectors and HPFP first.

It may be that the car doesn't register changes that happen during a DPF regen as problematic, like the fuel supply, because it's normal during regeneration, and the parameters aren't associated with any codes despite being abnormal during regular operation outside of regen. Your engine coolant temperature sensors are reading normal. 194F is normal.

I haven't checked fuel rail pressure, I don't have a reader.
Now that I think about it, it has been an intermittent issue for some time now, that comes and goes.
I would always check the coolant level (past issues/PTSD), and there was always plenty in the reservoir, and never put further thought into it.

 

[Zakh55]

I haven't checked fuel rail pressure, I don't have a reader.
Now that I think about it, it has been an intermittent issue for some time now, that comes and goes.
I would always check the coolant level (past issues/PTSD), and there was always plenty in the reservoir, and never put further thought into it.

If you open the HPFP, the fuel system has to be reprimed. That's diagnostic work that I wouldn't do as a DIY project because of that fact.

The amount of fuel going through the injectors can be monitored by vag. Check the Ross-Tech forums. I can guarantee there's a guide.

It will give you a readout of the fuel injected per stroke, the range (idle vs under load), and you can make an A/B comparison.

 

[Pilot91]

If you open the HPFP, the fuel system has to be reprimed. That's diagnostic work that I wouldn't do as a DIY project because of that fact.

The amount of fuel going through the injectors can be monitored by vag. Check the Ross-Tech forums. I can guarantee there's a guide.

It will give you a readout of the fuel injected per stroke, the range (idle vs under load), and you can make an A/B comparison.

I will look into it, thanks

 

[ZippyNH]

Engine RPM is not slightly elevated like it would be during a regen, holds at the normal ~800 RPM
Oil was not low when I checked the other day. It does burn oil, but falls above the limits for VW. I need to add a qt. every 1800-2200 miles

Regens cause the oil level to go UP due to unburnt FUEL getting past the oil control rings....
Same for a leaking/streaming injectors..
Regen are after all just a call for extra fuel to be injected on the exhaust stroke....
A leaky injector or streaming injector can cause it to look like you have a constant Regen... typically most people catch it from oil dilution in a test at an oil change or the oil level going UP.....or suddenly the engine seems to be not burning as much oil.

How does the engine start? Long crank like loss of prime after it sits or does it start right up?
Stumble at all after cranking? Smooth idle?

An actual Regen typically has a slightly elevated rpm at idle, some notice a slightly rougher idle.
A "passive" Regen can occur in typical cruising at higher loads and lower rpms I believe where the DPF just gets hot enough WITHOUT extra fuel to burn off collected soot.....

Any chance of getting an ash load on the DPF?
Sure that bit of into will shed some light on what's going on and help others figure out what's happening.

 

[Pilot91]

Regens cause the oil level to go UP due to unburnt FUEL getting past the oil control rings....
Same for a leaking/streaming injectors..
Regen are after all just a call for extra fuel to be injected on the exhaust stroke....
A leaky injector or streaming injector can cause it to look like you have a constant Regen... typically most people catch it from oil dilution in a test at an oil change or the oil level going UP.....or suddenly the engine seems to be not burning as much oil.

How does the engine start? Long crank like loss of prime after it sits or does it start right up?
Stumble at all after cranking? Smooth idle?

An actual Regen typically has a slightly elevated rpm at idle, some notice a slightly rougher idle.
A "passive" Regen can occur in typical cruising at higher loads and lower rpms I believe where the DPF just gets hot enough WITHOUT extra fuel to burn off collected soot.....

Any chance of getting an ash load on the DPF?
Sure that bit of into will shed some light on what's going on and help others figure out what's happening.

Drove it this morning to have an inspection, of course nothing happens. Running normal.
Starts all have been normal, literally nothing abnormal about them. 99% of my driving is all highway, 45 minutes each way to work, so passive regens should be normal. I have felt active regens while driving and idle.