PorKen

Were the special S4-up larger lower o-rings used when the old injectors were put back in?

safulop

Hmm well, they did use new o-rings but I can only assume they used the right kind of parts. Might need to check up on that. . .

dr bob

There's a BIG difference between the booster check valve and the the check valve by the booster that helps maintain vacuum in the reservoir for the HVAC and cruise control systems, and for the intake flappy control on S4+ cars. The booster check valve plugs into the grommet on the brake booster itself, helps maintain vacuum in the brake booster only.

safulop

Oh jeez, didn't know there were two different check valves. I'm pretty sure we only changed the one with the booster grommet (cuz I got that part from Roger to go with the check valve). Interesting, then, that it fixed the comb flap issue. Could simply have been bad lines/connections. But I will see about the *other* check valve next time. . .

dr bob

The check-valve for the HVAC/Cruise/Flappy reservoir has small tubing nozzles at both ends of a small 2-colors barrel that's about the diameter of a dime.

The brake booster check valve gets the ~10mm ID hose from the eductor (commonly somewhat misreferenced as a venturi) next to the throttle quadrant on the side of the intake manifold. It slips into the booster grommet with a similarly-large single-barb nozzle. OD of the check-valve section is about an inch or so.

safulop

OK here's a baffling statistic -- after 2 or 3 tanks of 11 mpg, my mileage is improving significantly. I'm now over 12 mpg on my last tank, which is what I had generally run in all-city conditions in hot weather using AC over the past 5 years.

By what miracle would mileage improve spontaneously? How long does the adaptation circuit take to figure things out?