Idle speed

[wrecking-crew]

What is a normal idle speed for a 2.9? Mine is at 850-1000 all the time.

 

[177CIOfPureLove]

Believe that auto equipped had a curb idle of about 800 rpm warm, manual's have a curb idle of about 850. You want the idle a lil higher than 800rpm with a stick, makes the truck much easier to drive. That is why they have two settings. You should have a sticker under the hood that gives you this spec as well.

The 1000rpm your seeing is when its still cold right? Even if not, my experience with my 1st gens dictates that the earlier computers are more prone to, "float" the idle number around than rather it always being constant, however mostly remaining in spec. my 89' has always been managed smoother with the newer computer. also check your idle voltage at your tps, should be at the spec. voltage as well.

 

[jhammel85]

Mine sure floats. If it does though it's only between 100 rpm or so. Usually sits at 800-850. Sometimes I'll see it at 750-850.

 

[177CIOfPureLove]

Yeah, my 88' does the very same. I think its all in the first gen issued computer. I remember seeing someone had put a later computer in a first gen and it ran it better. It is not a big enough concern for me to ever do.

My first BII, that thing was a treat, it was an automatic, and whenever you started it cold, it ran the engine to about 1600 rpm for about 45 seconds and stepped down to about 1000 rpm until it was warm. Its just how eec IV decided to run it.