Self-Service Gas: AXR Explained

Hello!

I'm experiencing the following problem, which occurs mainly when the engine is cold (car: Golf 4, AXR engine, manual transmission, manufactured in 2002, no GRA system, no auxiliary heater): the engine unexpectedly increases its RPM. This is noticeable during coasting, for example, when the car is slowing down towards a traffic light. The RPM then suddenly jumps to around 2000+ /min, which could be very unpleasant right before stopping at a red light.

I've also tried searching for a solution, but I haven't found anything except maybe replacing the temperature sensors for fuel and coolant. However, I can't really explain why the engine speed increases to over 2000 rpm because of that, to be honest.

Otherwise, no abnormalities were observed on the engine: performance is good, oil consumption is minimal, and fuel consumption is just over 7 liters in winter with daily use of the auxiliary heater.

Hat jemand Tipps? "Thank you!"
101das

P.S. Oh yeah, and no errors were stored in memory...

"Incorrect temperature seems plausible. What does the error memory say?"

101das wrote:

Hello! "I'm experiencing the following problem, which occurs intermittently, mostly when the engine is cold (car: Golf 4, AXR engine, manual transmission, manufactured in 2002, no GRA system, no auxiliary heater): the engine unexpectedly revs up on its own. This is noticeable during coasting, for example, when the car is slowing down towards a traffic light. The RPM suddenly jumps to around 2000+ /min, which could be very unpleasant right before stopping at a red light." ...

What is the software version of the engine control unit (ECU)?
If the part number is 038 906 019 CR, that could be the source of your problem. Replace it with a 038 906 019 MQ.

/viewtopic.php?t=1671&highlight=019+cr
/viewtopic.php?t=1726&highlight=019+cr

... if you can also confirm that the engine briefly increases its RPM to 1200-2000 RPM when starting (this doesn't always happen, but occasionally), then it looks suspicious and could be related to the G62 engine temperature sensor.

That's at least how it seemed to me, with other potential effects on the automatic transmission as well.

Due to the incorrect values from the temperature sensor, the fuel mixture is calculated incorrectly (too rich), which leads to fluctuations in engine speed or jerking during driving.


Sven.

Me again, with an update:

After replacing both the temperature sensors for fuel and coolant temperature, things seem quiet now; the problem is probably solved!

Thank you!