You have a MAF voltage fault and you have the MAF voltage rigged on a switch right?? Do the lights dim when you are trying to crank? Is the battery in good shape? I think the EWS can cause no-crank or no start depending on what conditions are met but I don't remember exactly how that works. It would have been good to get a bigger and maybe better gauge along with some fuel line hose to splice your adapter to so you could get a more accurate idea of your fuel pressure and easier to read while driving. With a longer hose it would be good to have the proper bleed valve at the gauge but you can probably get away without that.

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1988 325is (purchased new) sold
2004 X5 3.0 2005 X3 2.5
2008 X5 3.0 (new to me)