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Old 06-29-2003, 06:37 PM
ctaylor738 ctaylor738 is offline
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Join Date: Apr 2000
Location: Falls Church, VA
Posts: 5,315
Throttle Vacuum on a 3.8L V8?

I am still chasing the lumpy idle on my 380SL (Wayward Woman). I recently replaced the injectors, seals, and all the rubber plumbing on the intake manifold. This solved about half of the problem if such things can be quantified.

My question -

The throttle housing has two vacuum lines. One connects to the distributor's vacuum advance via a temperature switch, the other to what looks like an emissions cannister.

I took a vacuum reading off these lines and found I was getting zero vacuum at idle. As I brought the RPM's up, I started registering vacuum about 2000 RPM, and had about 7-10" at 2500 RPM.

Manifold vacuum at hot idle is a wobbly 15-16"

Does this sound right? TIA.
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe
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