Ok,
After a week of going crazy with high idle and bouncing idle and all the annoying trials and tribulations of removing and reinstalling the throttlebody, I've figured it out, and I wanna share.
First, DO NOT DO THE COOLANT BYPASS MOD! It sucks and it makes your car idle high all the time in any weather below like 80 degrees (had it for a year). Make sure you have the proper amount of coolant (8 quarts) in your system. Start the car, let it warm up, and have the radiator caps loosened. once the small overflow resevoir fills up, cap it. Watch the filler neck by the pass. side of the engine, squeeze the hoses and burp all bubbles out of the system. Try to just keep the water level up in the neck so it can't suck air back in, and be careful the stuff gets hot! Squeeze the hose till the fluid is all the way to the top(ready to spill out) and cap it tightly. Once you're content all air bubbles are out, move onto the next step.
Why worry about coolant? Bubbles in the IAC are bad and make idle fluctuate in a slow, annoying way.
OK, you NEED a timing light, no ifs ans or buts about this. Without the timing light none of this will work. Insert a jumper pin between the ten and gnd pins. Hook up the timing light to the battery for power and hook up the signal to the #1 wire location on the disty(make sure all 6 plugs will still get full spark). Loosen the two 12 mm bolts on the disty so it can rotate(not too loose). Now, with the jumper pin inserted, start the car, if it dies, then open the idle air screw on the top of the tb a couple turns.
Make sure the car is warmed up, NO accessories or fans or anything is on, and if the idle is like 1500 then close the idle air screw a little, it should be open 2-3 full turns. Now, move the power steering hoses and wires out of the way, point the flashing timing light at the crank pulley, and watch the small tab on it illuminate and reference it's location to the small timing marks on the plastic tab that sticks out over it. Rotate the disty until the notch on the crank pulley is exactly in line with the "10" on the plastic timing mark indicator(this is 10 degrees before top dead center). Now when it's at 10, tighten the disty down carefully so as not to move it. Double check for 10 deg. btdc. Now adjust the idle air screw until your idle sits right at 650 rpms (+/-25). Turn off the car, remove the jumper pin.
Do not adjust the idle air screw unless the car is running with the ten/gnd pins jumped!!!!!
Now, get your voltmeter. Set it to ohms. Touch the two terminals on the idle air bypass control valve(black part on bottom of tb). The resistance should be 10.2-12.3 ohms. If so, then that is ok. Unplug the TPS, with the voltmeter still on ohms (or continuity check mode), touch the two lowest pins with the terminals of the voltmeter. There should be continuity. If not, loosen the two screws holding it so you can just rotate it, and rotate until you get continuity. Next, take a .006"(.15mm) feeler gauge, and put it between the throttle stop screw and the throttle linkage(back/top of the TB) Before doing that, make sure that the stop screw that the linkage hits JUST barely touches it at closed throttle.(2.5mm allen key wrench for it). Now with the feeler gauge inserted, there should still be continuity, if not, rotate until there is. Next, switch to a .020"(.50mm) feeler gauge in, there should not be continuity, if so, redo the previous step until it is correct.
Plug the sensor back in, turn the key to the on position with a paper clip jumping the ten and gnd pins.Now measure volts, and put the black from the voltmeter on the neg. terminal of the battery, and tap into the yellow(2nd wire down from top of tps harness). Voltage should be between .1 and 1.1 at closed throttle, but I found .5 to be perfect. At wot it should be 3.6-4 volts(check by pressing gas pedal to ensure it opens fully).
Now start the car, your idle will be perfect. Don't bother resetting the battery! Let it adjust for the next few miles of driving. Throttle let off MAY be a little little jerky, but that's how mine has always been, when it was ever smooth the car wasn't idling right. Notice how quickly the rpms drop off and goto 650 when you pull to a stop
There, hope that helps, post questions here if you have them, but make sure you follow this word for word, step by step for accuracy. I referenced a good bit of this from my Ford Technical Manual.
Nick
After a week of going crazy with high idle and bouncing idle and all the annoying trials and tribulations of removing and reinstalling the throttlebody, I've figured it out, and I wanna share.
First, DO NOT DO THE COOLANT BYPASS MOD! It sucks and it makes your car idle high all the time in any weather below like 80 degrees (had it for a year). Make sure you have the proper amount of coolant (8 quarts) in your system. Start the car, let it warm up, and have the radiator caps loosened. once the small overflow resevoir fills up, cap it. Watch the filler neck by the pass. side of the engine, squeeze the hoses and burp all bubbles out of the system. Try to just keep the water level up in the neck so it can't suck air back in, and be careful the stuff gets hot! Squeeze the hose till the fluid is all the way to the top(ready to spill out) and cap it tightly. Once you're content all air bubbles are out, move onto the next step.
Why worry about coolant? Bubbles in the IAC are bad and make idle fluctuate in a slow, annoying way.
OK, you NEED a timing light, no ifs ans or buts about this. Without the timing light none of this will work. Insert a jumper pin between the ten and gnd pins. Hook up the timing light to the battery for power and hook up the signal to the #1 wire location on the disty(make sure all 6 plugs will still get full spark). Loosen the two 12 mm bolts on the disty so it can rotate(not too loose). Now, with the jumper pin inserted, start the car, if it dies, then open the idle air screw on the top of the tb a couple turns.
Make sure the car is warmed up, NO accessories or fans or anything is on, and if the idle is like 1500 then close the idle air screw a little, it should be open 2-3 full turns. Now, move the power steering hoses and wires out of the way, point the flashing timing light at the crank pulley, and watch the small tab on it illuminate and reference it's location to the small timing marks on the plastic tab that sticks out over it. Rotate the disty until the notch on the crank pulley is exactly in line with the "10" on the plastic timing mark indicator(this is 10 degrees before top dead center). Now when it's at 10, tighten the disty down carefully so as not to move it. Double check for 10 deg. btdc. Now adjust the idle air screw until your idle sits right at 650 rpms (+/-25). Turn off the car, remove the jumper pin.
Do not adjust the idle air screw unless the car is running with the ten/gnd pins jumped!!!!!
Now, get your voltmeter. Set it to ohms. Touch the two terminals on the idle air bypass control valve(black part on bottom of tb). The resistance should be 10.2-12.3 ohms. If so, then that is ok. Unplug the TPS, with the voltmeter still on ohms (or continuity check mode), touch the two lowest pins with the terminals of the voltmeter. There should be continuity. If not, loosen the two screws holding it so you can just rotate it, and rotate until you get continuity. Next, take a .006"(.15mm) feeler gauge, and put it between the throttle stop screw and the throttle linkage(back/top of the TB) Before doing that, make sure that the stop screw that the linkage hits JUST barely touches it at closed throttle.(2.5mm allen key wrench for it). Now with the feeler gauge inserted, there should still be continuity, if not, rotate until there is. Next, switch to a .020"(.50mm) feeler gauge in, there should not be continuity, if so, redo the previous step until it is correct.
Plug the sensor back in, turn the key to the on position with a paper clip jumping the ten and gnd pins.Now measure volts, and put the black from the voltmeter on the neg. terminal of the battery, and tap into the yellow(2nd wire down from top of tps harness). Voltage should be between .1 and 1.1 at closed throttle, but I found .5 to be perfect. At wot it should be 3.6-4 volts(check by pressing gas pedal to ensure it opens fully).
Now start the car, your idle will be perfect. Don't bother resetting the battery! Let it adjust for the next few miles of driving. Throttle let off MAY be a little little jerky, but that's how mine has always been, when it was ever smooth the car wasn't idling right. Notice how quickly the rpms drop off and goto 650 when you pull to a stop
There, hope that helps, post questions here if you have them, but make sure you follow this word for word, step by step for accuracy. I referenced a good bit of this from my Ford Technical Manual.
Nick
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