If you wanted, you could use one of those 5-prong relays for your fuel pump, then connect the other output (the "center" prong) to the check engine light so that it comes on whenever your fuel pump is off...
A very good idea, something I didn't think about. Thanks.
I was thinking a Hobbs switch that was set to open at a low vac, setting and a bypass switch for the 99.999% that I didn't need to worry about the Check Engine light.
But I think Bob's idea sounds like a cleaner setup.