Some questions about idle and boost

[drk mrk iv]

I finally got my car running the other day. When I crank it up the idle kind of jumps around. It almost stalls, but then catches and idles relatively smoothly at 1k. Then it will slowling climb to 1.3-1.5k and then slowly go back down. This happens after I have been driving awhile. And, what is the difference between 12 lbs of boost and 15lbs of boost on a T25? I have hardpipes and 2.5 inch exhaust. 20horsepower? Thanks.

 

[evolvingGS-t]

Sounds like idle surge? Are you VTA?

 

[sanguinefaery]

sounds like idle surge...my car does it too I just haven't fixed it yet. A number of different things can cause it. Check the base idle set screw located on the throttle body (<a href="http://members.shaw.ca/dsm.1000q/Engineprimer/1G/biss.htm">here</a> is a good pic of it) if it wiggles around and such or just turns with your finger...that could be part of the problem.

Here is a great write up on how to diagnose idle surge <a href="http://www.dsm.org/how-tos/tttt/tttt3.html">http://www.dsm.org/how-tos/tttt/tttt3.html</a>

 

[drk mrk iv]

The BISS is fine as far as wiggling. I should explain the situation better. It will idle at 1k after a little while and then will creep up to 1.3-1.5 and stay there until I tap the gas and it will fall back down to 1k and be just fine.