Originally Posted by
David T
From the many posts in this forum concerning the Primary Pressure Regulator, it would seem, once you mess with the "O" rings, there is a high failure rate. I don't know if it is due to the replacement "O" rings not being the correct size, something about how the new ones are installed, or what, but once you touch that regulator it seems to become a problem if it wasn't before. IMHO the primary cause of loss of rest pressure is the fuel accumulator. Next would be the check valve at the fuel pump. Leaks are a possibility but they are very noticeable. The PPR is the LAST likely suspect unless it has been tampered with. Then it seems to become the #1 cause. Bottom line, unless you can rule out all other possible cause you should not touch that PPR.