I have an 87 305TPI with an automatic bone stock except for the wiring harness that was changed by the previous owner. It idles really high and has since the day i got it. I have checked all the connections and realays and they all check out good. all the sensors seem to be getting the correct volatge. i have tried to set the minimum idle by IAC and it desnt drop below 1500 even with the idle scew COMPLETELY out. the TPS is at .54 at idle and 4.5 at WOT. I have sprayed the intake with water to see if it changes the idle and it doesnt so there is no leak. i have also disconnected EVERY line individually to eliminate that possibility. Could it be my computer? I have checked all the voltage coming from the computer based on the wiring diagram and everything is good. Could the computer itself be fried? The check engine light stays on but it wont let me pull any codes when i jump it. I also tried to run winaldl and it wont give the computer any info. ANY HELP would be greatly appreciated.

the car has the 1227165 ECM in it if that helps.

John34683@yahoo.com

 

does the blade on the throttle body actually closed down to the idle screw? mine have a ridge on the inside that stops it from closing down to the idle screw. Jump A and i think D connector on diagnostic port with a wire or something.(two top on the right). Then turn the key in on position for 30 seconds. Unplug IAC(you should hear it closing before you unplug). And then start the car. If idle is good then possibly IAC is bad.

 

It wont let the blades close past a certain point. I tried to do the jumper to reset the iac and when i unhook the iac it makes the car idle even higher than before.

 

if the point is before it hits the idle screw then the problem is the throttle body it self.

 

are the blades supposed to close all the way until they hit the throttle stop? (the piece of metal that the idle screw is in)

 

also, when the car is cold i have to hit the throttle in about half way and let it crank over for about 30 seconds before it starts. Then when it does start it chuggs and dies unless i hold it at 3500 and let it even itself out and then it goes back to 1500 and stays there. I have an aftermarket fuel pressure regulator on it and at idle it holds about 38 p.s.i. and goes up rapidly when i rev the motor. When i turn the car off it holds the fuel pressure for a few minutes and then trickles back down to about 15 or 20 psi and holds there. I really appreciate your help, i have to get this car running right or i will have to sell it. Its our only car and we have a 1 1/2 year old and another on the way. the wife says if it isnt dependable and getting better gas mileage it has to go. please shoot ANY ideas you guys might have.

 

Checking for vacuum leaks with WATER? You need something combustible to detect a vacuum leak, ESPECIALLY a small one. Try a propane torch with a piece of 5/8 rubber hose attached to the end and go over the intake base, TB mating areas, runner mating areas, even around the base of the fuel injectors to detect leaking injector o rings. Water won't work, don't know who told you to do that.