Setting idle speed

[Ryunker]

So setting idle speed, 351c m code. Books show like 600rpm, cant seam to get there, lowest is like 800. Runs OK, but when you put it in drive, idle is way too slow.

What is the correct procedure for setting idle speed?

 

[c9zx]

Turn the mixture screws out 1/4 turn. If that makes it worse, turn the mixture 1/2 turn in from there. A vacuum gauge monitoring manifold vacuum would be helpful. Chuck

 

[Ryunker]

Turn the mixture screws out 1/4 turn. If that makes it worse, turn the mixture 1/2 turn in from there. A vacuum gauge monitoring manifold vacuum would be helpful. Chuck

Will do tomorrow night. What am I looking for on guage?

 

[Don C]

With an automatic transmission the idle speed is usually set with the transmission in drive (see section 24-21-03 in the shop manual).

 

[Galucha]

Will do tomorrow night. What am I looking for on guage?

You're looking for highest vacuum reading as you turn the idle mixture screws in or out. With a mild or stock cam, the reading should be relatively steady somewhere between 12-20 in/hg. If the gauge is bouncing all over the place, you will have to address what's causing it to do that before you set the idle mixture (vacuum leak, misfire, incorrect timing, etc.). Make sure you turn both mixture screws in or out equal amounts.