idle surges between 1000 rpm and 2000 rpm.... no vaccuum leaks i just tried redoing every line and no luck. Any other suggestions ?

 

unplug the bac, wind out the thermowax adjustment so it has no effect, see what it idles at now, adjust at the throttle body until 750.

 

How did you verify there was no leaks?


-Ted

 

i verified that by changing every line and then checking it with a propane torch

 

Propane torch, good, so we dont have to listen to this anymore. Do what the rest of us have done and research. Im still new to this club, but spend some time reading. How is your AFM, BAC, ACV, O-2 sensor, what are your trouble codes? Have you checked TPS- adjusted it, throttle cable, checked LIM, timing, grounds to your engine, is your driver side airbag working? Sorry, been up all night trying to figure out if yellow and blue do really make green.LOL, and read my threads, and then get back.

 

Propane torch doesn't always work.
I've used propane torches before that didn't catch vacuum leaks like a spray can of starting fluid...


-Ted

 

Appologies for my attitude, but what year, and is it surging cold, warmed up, what year and which car? Like RETed said, easier to find leaks with starting fluid or I use carb cleaner. Check around LIM and adjusting TPS seems to always fix my 1990 FC3C vert.

 

I found that when the throttle plate gap is set too wide, I get that pulsing idle. Base setting is very narrow. That plus making sure the TPS was set correctly. I first set it at dead-on 1K OHM fully warmed up. Then I attached the twin test lights and both were lit, so I adjusted the TPS to where only one lit. Went back and checked the resistance and it was about 1065. I left it there and went on an extended test drive...perfect idle and no pulsing. Came back and rechecked the TPS setting. still at 1065 and 1 light lit.