five7kid

iTrader: (14)

My son's S10 Blazer 5.3-bored-to-5.7 swap uses a Vette filter for fuel pressure control (with aftermarket in-line pump). Initial dyno runs showed it going lean under power, so we dropped the tank and installed a new pickup/pump assembly, kept the in-line because we weren't sure the 4.3 pump would keep up with the 5.7 (he's on a student budget, so decided not to upgrade the in-tank pump). At the same time, we installed a fuel pressure gauge on the fuel rail (Wilson rails), as well are replacing the filter/regulator (a Wix unit, IIRC). At that time, it showed a nice steady 58-59 psi, including under power. (Oh, the lean problem turned out to be the stock 5.3 injectors the swapper used, about 22 lb/hr, being too small and going 100% DC).

The damper spun on the crank last July, so the truck has sat since then. He had just filled the tank before that happened (I didn't think to put some stabilizer in the tank, because I didn't think it would be down this long). Last night we got it running again, and the fuel pressure now reads about 63-65 psi. We only ran it at idle and gave it some quick throttle blips from time to time (fresh rings and bearings, didn't want to run it too hard), and the pressure would momentarily drop down to 61-62, but would quickly recover to 65.

Seems kind of weird, but wondering if something happened to the regulator while it sat these last 8 months. We'll see what it does after it's been driven a bit, but may end up changing the filter.

Wondering if anyone has seen this type of behavior.