i just recently put a new head on my 86 and when i start the ****** it idles at about 4 grand..it starts out where it used to at 2, 400 but then climbs to just under 4. I made sure the cam timing was correct and has enough tension on the belt. I didnt do a vacuum test yet but to be revving that high it would have to be a huge leak. Any suggestions about what else i could try?

 

Did you make sure your thottle body ain't open any ? Also check for leaks, if your Thottle body is stuck open alittle with a leak, then it would be this high.

 

Is it carbed? The choke could be stuck.

 

Yaw. Was that year Carbed??? That would be a good start....

 

mine is not carbed had major idleing issues so I jumped in and figured most of them out. does the Idle change drastically when the AC is on if so turn it on and adjust the Idle screw out till it idles down. 2nd question does it lobe at idle? if so there is a disc shaped thing cant rember what it is called it has 2 screws in the top philip head screws take them out and tighten the thing with slots in it this will fix it

 

all Si's are fuel injected, hence the "i" in Si.