anyone had this problem?

[mirkoelek]

its my friends gsx 97, with 550cc and afc2, idle is not constant. It's working weird, it goes to 2000 rpm than goes back to 1000 , then again the same thing, this repeats every second.
he has com101101 or whatever cams but i dont think this will happened because of that

 

[Turbocharged]

Check the resistances of the ISC pins. If the resistances between pins 1-2, 2-3, 4-5 and 5-6 are not between 27-33 ohms he needs a new ISC.

Try adjusting the BISS screw. If it is adjusted too far out, too much air will be bypassing the throttle plate. This will result in the symptoms described.

 

[mirkoelek]

you have to tell me what is isc and biss

 

[quiksilver38]

idle speed controller=isc mines flaking out and the part is kinda exprensive it reads a p0505 scan code from the service engine light. i got one from the junkyard and it was junk

 

[Turbocharged]

BISS = base idle speed screw

The BISS is on the top front of the throttle body. You turn the screw to set your idle higher or lower. The ISC is located on the bottom of the throttle body. Take the connector off and test the resistances of the pins on the ISC.

The problem could also be caused by an intake leak after the throttle body. Do a boost leak test.

 

[mirkoelek]

how would you do that after throttle body

 

[Turbocharged]

A standard boost leak test will show if you have any leaks after the TB.

 

[oldman]

Obviously, the problem didn't just come out of no where. Tell us everything that was done to the car recently.