[Nick H]

That's a huge difference, nice one. Great to have real world results to back up the theory, happy days.!

Nick.

 

[Nick H]

That could be it then, that the ECU can calculate the difference between actual airflow and what it expects to see, because it's assuming th EGR is still functioning normally.

Nick.

 

[Nick H]

Top Man
Thinking I might be a bit short of that figure.
Could my blanking of EGR make a difference? Guess not because it's after the MAF?

Thank-You

Blanked EGR will have the effect of increasing the MAF readings at a given rpm, as now the EGR is not recirculating exhaust gas into the cylinders, they become charged with more air, which is obviously drawn through the airflow meter.

Systems like Bosch EDC16 (a la 1.9cdti's) use this MAF reading to figure out if an EGR is blocked/stuck etc as it knows how much airflow it should be seeing at a given RPM/load/throttle, and hence why no EGR feedback on the actual valves on those systems.

Suspect your van isn't sensitive enough to pick up that the EGR has been blanked. Your idle figures are slightly up so this makes sense. I bet fully revved wouldn't be far off either. Have seen airflow meters fail on these but normally open circuit and fault codes.

At least she's running a treat now

Nick.