V8supra Posted May 7, 2012 Report Share Posted May 7, 2012 Got a buddy with a LS1 Trans Am 6 speed car. Says its built(who knows if it really is) Says when you start the car it idles rough then surges then tachs like 7k before it idles back down. Someone told him its the idle air control sensor... Do you guys have any idea what it could be. The OBD2 port dont work so we cant get any codes Any & All help would be greatly appreciated thanks Quote Link to comment Share on other sites More sharing options...
Rocky31186 Posted May 7, 2012 Report Share Posted May 7, 2012 Might need to start by figuring out what he considers "built" and who it's tuned by. With no scanning ability you will be cleaning / throwing parts at it. Quote Link to comment Share on other sites More sharing options...
V8supra Posted May 7, 2012 Author Report Share Posted May 7, 2012 thats what I am thinking lol here is what I know for sure is done to car Fulley Rebuilt motor arp bolts Aftermarket Pushrods Behive Springs Roller Rockers really thats all I honestly know of besides stage 1 clutch(as he put it) Quote Link to comment Share on other sites More sharing options...
Cordell Posted May 7, 2012 Report Share Posted May 7, 2012 I'm willing to bet theres no power at the OBD2 port, so check the cigerette lighter fuse and see if you can get codes. That would be a good place to start. I doubt the IAC valve is bad, as I'd be looking for vacuum leaks or a hanging throttle. Quote Link to comment Share on other sites More sharing options...
AJ Posted May 7, 2012 Report Share Posted May 7, 2012 +1 on the fuse blown. Almost sounds like someone forgot to hook up the vacuum line for the power brakes. Quote Link to comment Share on other sites More sharing options...
V8supra Posted May 7, 2012 Author Report Share Posted May 7, 2012 I was figuring on hung throttle or vacume leak. I will check the fuses. Dude is trying to trade it to me for a S10 I have its a nice car and all the stuff I listed above he has receipts for (heads have work also) but yea. Im going to look it over later. Quote Link to comment Share on other sites More sharing options...
Berto Posted May 7, 2012 Report Share Posted May 7, 2012 Might want to try 're learning' the IAC (idle air control valve) I had weird idle issues after I finished my swap, the IAC was not calibrated. To calibrate it, unplug the valve, then key on (do not run the engine) for some time (30 secs just to be sure) then key off. Plug the sensor back in, Key on for a few seconds then start it up. the IAC should be calibrated at that point. might fix the issues and is easy enough to try. Quote Link to comment Share on other sites More sharing options...
V8supra Posted May 7, 2012 Author Report Share Posted May 7, 2012 thanks nice RX7 in sig. I am about to swap a 87 Supra lol If we do the deal I will then be trouble shooting lol Quote Link to comment Share on other sites More sharing options...
GTPSS Posted May 10, 2012 Report Share Posted May 10, 2012 Get the OBD port working! IIRC its only 3-4 wires to verify worst case, but most likely a blown fuse as others have stated. Once you have codes, it should be problem solved. Quote Link to comment Share on other sites More sharing options...
V8supra Posted May 10, 2012 Author Report Share Posted May 10, 2012 looked at said car it had a big bunch of hack job(someone cut vacumes I fixed so I could hear motor right it was knocking in bottom end(So I figured it was so someone couldnt hear long enough to hear bottom end knock) Quote Link to comment Share on other sites More sharing options...
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