406oc.co.uk

Benjamin,

I believe the ECU will register a fault as the air flow won't match the expected values but doesn't actually throw up the EML or limp mode in the short term, what the long term effects are I have no idea.

This is correct: fault but no EML or limp mode.

if you plug the vac line to the egr there will be no fault registered if you unplug the vac valve on the bulk head there will be a fault registered

I'm not sure that's true.
I believe the fault arises because the MAF value is higher than expected when exhaust gas is supposed to be being recycled.

My 406 had an EGR map on it - even though it was blanked and it never threw a fault, even after a year....

I understand what RWB is saying, the engine is sucking all the air past the MAF, even though the ECU thinks the EGR is open so some of the air flow should be diverted and sucked past the EGR.

I'll be blanking the replacement car before I get it mapped, just to eliminate some issues.

rwbs car is a newer 707 or sum thing like that so is more sensitive to things being blocked and unpluged the 406 on the other had is quit basic in its computerization and can't tell if the egrs working corectley or not just if the electrovalve is plugged in and that is giving the correct feed back

Ben,

I recently did this with mine - I fitted the egr blank, left the electrovalve connected and didn't change the software. I disconnected/plugged the vacuum supply to the electrovalve, but this was more to eliminate possible vacuum leaks than any need to do so.

The car ran fine - no warning lights, BUT when I checked with the diagnostic computer it have logged a fault, "air flow higher than expected". While this did not cause any outward problems, you have to wonder if it would have done so in time. No big deal for me, since I could simply reset it if necessary, but I decided to download a no-egr map, since I had one available.

Blanking the egr alone gave me an improvement in driveability and about 2 mpg more, installing a no-egr file gave me at least the same benefit again.

My story is buried in this post:viewtopic.php?f=1&t=21954

I'm not suggesting it would damage the engine, but it might eventually cause you a warning light / limp mode situation.

No doubt others will tell you their's have been OK for years. I am just trying to give you the full picture.

I believe your engine will have 2 electro valves mounted on the bulkhead, standing at the front of the car the left hand one being turbo, the right-hand being EGR...but.....
As you'll be installing a blanking plate the simplest and guaranteed way to identify the EGR electro valve is to remove the turbo pipe and follow the vac pipe from the EGR back to the electro valves.
To eliminate future vac leaks I removed the vac pipe completely and blanked it prior to the electro valve but left the electrical connector plugged in.

blue plug is the best way to identify the egr electro valve

Are those electro valves the things on the bulkhead that carry on whirring after engine switched off?

Mine has 3 of them if so....

Check your banking plate isn't leaking and that you have no boost leaks elsewhere.

If the vac line isn't sealed properly and you're losing vac pressure it might cause the turbo actuator to misbehave.
I believe poor vacuum on the 110 holds the waste gate open but could be wrong, someone with better knowledge will confirm or deny I'm sure.

As Doggy says make sure the blanking plate is sealed properly, did you use high temp liquid gasket and allow it to cure?

ye put a clip round the plug in the vac line

There should have been a copper gasket under the EGR, the copper will deform as the EGR is tightened down. The blanking plate will be a soft metal but not soft enough to deform and fill any gaps hence the need for liquid gasket.
Personally I'd be inclined to plug the vac pipe at its source, it will feed from a 'T' from either the vac pump or the brake servo. Can't remember where t fed from on my 2.2 as a lot of rubber pipe was liberated from my car that afternoon