Re: Egr bypass EB Xr8
i have had a bit of experience with egr valves and why they can cause excessive fuel consumption when removed or blocked off.
EGR valves were implemented to reduce exhaust emissions in mid to late seventies here in australia on all local and import vehicles.
The egr is activated by a vacuum diaphram from the carby or on efi from the manifold or upper plenum, some use a isolating solenoid to stop egr opening at cold engine temps, or to open it from the ECU. They mostly open in the mid, or high rev range, but can fully open with wide open excelerator at low rpm(low vacuum).
On the 4.1 six in the XF(efi), it is common to find the runner tube blocked with carbon and nitrites, from the exhaust passing throught the egr into the upper plenum, this will cause error code(code34) when interogating the ECU.
How the ECU knows the egr is not flowing is because the engine speed will be higher, then if the egr was open.
In reply to the first thread, without the EGR the engine will run richer, you can remove the EGR or block it off, but remapping the ECU will be required to bring the engine back into optimum state of tune, as the ECU is programmed to run with a EGR, and also that vehicle complys with ADR's in relation to Exhaust gas recirculation. i would consult your local automotive engineer and get second opinion. good luck
2011 FG GT boss 335 6sp man build no178