EGR

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Originally Posted by Fatso

Gday dougal , been trying to find an answer to a question re egr blanking , blanked my MY7 RRs td6 (Jan 2007) egr,s and after a few weeks got a PO402 code sitting in the ecu but no alarms or CEL nothing to indicate a problem and eng goes a lot better . apparently it is ok to blank pre 2007 but not post 2007 due to more egr monitoring . Question is could the PO402 (excessive egr flow) be a problem latter on if left or ignored , what happens to the fueling in this condition . Al

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The code will be because the airflow doesn't match expectations. I have no idea what that particular engine does fuelling wise in those conditions, but a remapper can flatten the EGR flow tables and prevent that trouble code from re-curring.

On my work car (completely unrelated other than being a diesel with EGR) I had EGR blanked, but a flat-spot in performance. I had to get into the ECU and flatten the EGR flow tables to get rid of the flat-spot.

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Originally Posted by Dougal

For the shift points to change, a sensor is now reading a lot different to what it was previously.
That is driving your differences. Conditions in cylinder don't alter shift points.

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However available power at a given engine rpm will affect the torque converter lockup and whether to drop a gear.

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Originally Posted by Gerokent

Who ever invented the EGR system should hang their head in shame.

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Saab had to fit an EGR valve to one of its vehicles purely to comply with a particular country's law that required it to be fitted, nothing to do with actual emissions.

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Originally Posted by Graeme

However available power at a given engine rpm will affect the torque converter lockup and whether to drop a gear.

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True, but he was talking about gentle throttle also.

Hi Dougal. Just blanked, no remapping, and no fault codes. Jim

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Originally Posted by Dougal

True, but he was talking about gentle throttle also.

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I don't understand your point because its on gentle throttle that EGR is normally operational and possibly where the worst EGR effect on torque occurs.

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Originally Posted by Dougal

How can you not be trolling?

For a start, there is no throttle to close. Diesels are controlled on fuel alone. If the actual rpm is higher than the requested rpm, then fuel is reduced or cut completely. This continues until the requested speed is reached.
Same thing when the requested speed is idle speed.

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I did actually say first up pardon my ignorance ...:angel:

Re throttle, my mistake I should have been clearer, as a motorcyclists first and foremost in that method of transports terminology a throttle is the thing you hang onto and twist on or off to go fast or go slow. It does not refer to the method of fuel delivery, be it carburettors or fuel injection or anything else.

My main point was if any motor is idling then it will be using fuel to keep idling, whereas you were saying a diesel will use zero fuel.

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Originally Posted by Graeme

I don't understand your point because its on gentle throttle that EGR is normally operational and possibly where the worst EGR effect on torque occurs.

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With gentle throttle, you are producing only little amounts of torque, a long way from kick-down and the T/C we'd expect to be locked unless it was in a gear/speed range where it wasn't practical.

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Originally Posted by TerryO

My main point was if any motor is idling then it will be using fuel to keep idling, whereas you were saying a diesel will use zero fuel.

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Only in over-run. I.e. being driven by the wheels.
Surely it's obvious that an idling engine needs fuel?

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Originally Posted by Dougal

Only in over-run. I.e. being driven by the wheels.
Surely it's obvious that an idling engine needs fuel?

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Yes it is obvious that a idling engine needs fuel and that is why I pointed it out, because that is not what you said.

On occassion you do ridicule others when you see a hole in their comments rather than explaining in a friendly manner where they went wrong or just ignoring them.

So why shouldn't others do the same in return to you? Better still how about we all cut each other some slack so this forum stays a friendly and inviting place to visit?

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Originally Posted by TerryO

Yes it is obvious that a idling engine needs fuel and that is why I pointed it out, because that is not what you said.

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This is what I wrote:

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Originally Posted by Dougal

There is nothing pedantic about correcting those applying petrol engine theory to diesels.

How exactly do you disagree with the fuel cut?
The fuel use display in your own vehicles will show a big 0.0 litres/100km whenever you lift off.

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