Ignition tune up questions

[canada karl]

I have new Bosch Super Plus spark plugs from Bavauto.....WR8 7907....is the plug gap for these plugs still .025? Also...some models have an independent adjusting screw on the throttle linkage which does not disturb the idle screw....does the 76 530i have this or how do you keep the idle at 1700 to set the timing at 22 degrees? I couldn't see any other adjustment other than the adjustment screw with the locknut. Thx CK

[T.Hanson]

See throttle body rebuilding and timing FAQ's.

Plugs for 528i are Bosch WR9 DS ( Silber) Google search past posts for fun with platinums, other non-spec tries.

[Mike W.]

There is an air adjustment in the throttle body for idle speed, the linkage should not touch the stop, but neither it nor the stop have enough to get it up to 1700 to time it. You pretty much need a friend with a steady foot on the gas pedal. Or take the stop screw out, put a bolt in from the linkage side with a head on it and adjust it that way. Removing it of course after setting the timing.

[canada karl]

and the car runs great except that the idle is at 1200 with the throttle aginst its stop? Any typical reasons for this? CK

[T.Hanson]

My 528i's...

The little screw / nut in the throttle body, (see FAQ) holds the butterfly lever just open, off the cast arm that the screw threads into. If you wanted to get picky about it, there are tiny holes in the big barrel of the throttle body. The screw holds the brass disc in position over one of those tiny holes.

If timed correctly, there is a big brass screw on the throttle body on the firewall side, down low. ( See FAQ.) Turning it meters air, or fine tunes the idle.

Predicated on everything else being like new, up to specs. If not, expect the idle to fluctuate; cold, up to temp, happy, heavy traffic, blah, blah.

My preference is 1000 to 1200 for that. Usually smoother if wrong, as I don't like lumpita, lumpita, futt threatening to quit just to save gas.

[Lenny D.]

and the car runs great except that the idle is at 1200 with the throttle aginst its stop? Any typical reasons for this? CK

An air leak?