Ed - thanks for that, looks like temp sensors are OK then.
OK, I took another log this morning (tried yesterday but it lost comms at the most crucial point, think it's my lead
).
This time I have logged blocks 008 and 011.
Parameters logged:
Engine speed (rpm)
IQ limit (driver request, mg/R)
IQ limit (rpm, mg/R)
IQ limit (MAF, mg/R)
Specified intake pressure (mbar)
Actual intake pressure (mbar)
MAP sensor duty cycle
This is how I understand Injection Quantities (IQ) to work:
There are 3 sources of information for how much fuel should be injected.
First there is the drivers request - IE how far down your foot is. Ranges from 0-70 mg/R.
Next is the maximum amount the ECU says can be injected at a given RPM.
Finally, is the maximum amount of fuelling the ECU says can be injected for the amount of air being sucked in (from the MAF reading).
The lowest of the three values is selected.
Intake pressures are straightforward: Specified is what pressure the ECU says it wants, actual is how much is generated by the turbo. Figures are in millibars, to work out boost you need to subtract atmospheric pressure (usually around 1000millibar give or take).
Here is today's log:
http://www.seat-ibiza-mk4.co.uk/files/LOG-01-008-011-xxx.csv
Some areas of interest:
- Time stamp range 518.43-527.23 was a steady cruise on the cruise control, road reasonably level but with some slight undulation. Was around 70mph in 6th IIRC.
- Time stamp range 810.84-830.03 was a full power run, I think in 6th.
- Time stamp range 985.88-1003.48 was a full power run, I think in 4th.
- Time stamp range 1964.45-2047.64 was a variety of full power bursts, as and when traffic permitted on a dual carriageway. Unfortunately a few gaps here and there due to traffic, but you can see the full power bursts as this is anywhere the IQ Driver request sits at 70mg/R.
A couple of interesting observations:
On full power runs, the limiting factor for the fuel injection quantity is the fuelling map (IQ from RPM). The IQ for the MAF readings is always slightly higher, suggesting there is always enough air coming in. However, it was smoking again today, which does fit in with the possibility of a boost leak - the ECU would see enough air coming in and inject enough fuel accordingly, but not all of that air is reaching the engine, causing slight overfuelling and smoke.
During just one of the full power runs, the specified intake pressure was approx 2.5bar, whilst the actual sat just over 2.6bar. Any theories on why this would happen ?
Over to you, my fellow geeks