I recently finished swapping the 13B in my 90 vert with a direct factory replacement. Everything works perfectly, but it's idling at about 1,200 RPM, when it used to idle at about 750. The throttle cable has a bit of play in it as it should, but I'm clueless. Adjustment issues or advice would be great.

 

Tight cruise control cable possibly.

 

I thought it was slack too, but I'll check again. Thanks.

 

Sounds like the fast idle system on the throttlebody might not be working right.



See the part that says Cam adjusting screw? It sits on top of the thermowax. If you physically lift that up, it will rotate around and drop the idle down. Normally the hot coolant should push the water thermo wax up and drop the idle down automatically.

Spec is 1-2mm freeplay for both throttle and cruise cables.

 

So if that screw isn't allowing the idle to drop, all I have to do is loosen it a bit?

 

You would do the opposite.

 

Ah. I'll look at that next then, once it's not 99* here.

 

The throttle mechanism on the back of the throttle body is directly tied to the throttle mechanism on the front of the throttle body, push one and it affects the other. So with the car idling press "upward" (not downward as that would cause the idle speed to increase) on the front throttle mechanism and see if it drops the idle or not and if it does then you know the cause.

 

Excellent. Thanks for the help, I really appreciate it.

 

If you push up on the linkage and there is no change there could possibly be a build up of carbon inside preventing the plates from closing as they should. You could eye the primary plate w/the intake tube disconnected and see what opening/gap you have. W/the engine off it should barely be cracked open. If the gap is larger than a slither you would manually apply upward pressure on the throttle linkage and see if it closes more.

 

I adjusted the cam screw today, it's now idling at about 800. I'll call that good. Thanks for your help.

 

So after I got my idle fixed, more problems arose. Now whenever I start the car, it goes to 3,000 like it should for the quick warm-up, but then it drops to about 1,000 and constantly bounces up to 1,800-ish. It's a very quick surging, and it does it until I drive the car a bit (until it warms up) and then it goes down to idle, like it should. Please help. I'm stumped on this one!