Anyone got the recommended idle rpm for a 1994 348 spider? And adjustment - any specifics, tips and traps. Thanks.
There are two adjustments that can affect your idle speed. one is the air bypass screws that are located on the throttle bodies these adjust bypass air around the throttle plates. The other adjustment is on the throttle linkage.There are two of each of these screws so they have to syncronised between each bank. IMHO if your idle is within the range discussed (around 1000 rpm when warm)in the previous thread I wouldn't do any adjusting.
Guys thanks for the quick response. Much appreciated. Mine's idling at an indicated 1000rpm, which is simply higher than I'm used to, but not a problem, so I can relax on that score now. On having a close look at the linkages I see that the throttle cable passes up from between the banks, goes around a curved piece of metal and then passes through a split retainer where it is held by two nuts (on the top). I was thinking there should be a nut on the underside of this retainer. Am I right?
From old archives. Connect a large U-tube mercury manometer to the intake plenum, one port on the 1-4 bank, one on the 5-8 (don't bother with vacuum gauges, doesn't work at all). Disconnect the idle air speed motors electrical connector and block their ports into each plenum. Balance the airflow relative to each bank by adjusting the brass colored screw on each throttle body. Do not touch the butterfly stop screws, the throttle bodies are factory set. Monitor idle speed, should adjust to about 1000 rpm, adjust with airflow bleed, not butterfly. Ensure that the exhaust is not blocked by a bad catalyst. Measure exhaust gas content for additional clues. Reset ECU's by disconnecting battery for about 10 seconds and allow them to "relearn". Last car I could not flow balance at idle was a Challenge race car and turned out to require valve reseating. So, you could also try a leak down test to see what's up if the above does not work. Best regards, Rob Schermerhorn
