John, You said it your self, 95% of the problems is the accumulator. The only check valve I have sold with out the fuel pump was to a shop who replaced the fuel pump that a Auto store recommended and they didn't know it needed a check valve, then the De Lorean owner wonders why he's having acceleration problems. Your statenments are correct. But: what do you do if you have the older long neck ver of the fuel pump 954 or 964 with a built in check valve. It can't be replaced. The 957 has a check valve that can be replaced. The other way to check the thermo time switch, is to check it for open or closed in hot or cold water. You can see the different fuel pumps on the site. John Hervey http://www.specialtauto.com/fuelsystems.shtml