YEAH I JUST REBUILT MY LB9 ,GOT IT TOGETHER 2 DAYS AGO AND WASNT ABLE TO GET IT RUNNING SMOOTH ENOUGH TO SET ANYTHING WELL TODAY I MESSED WITH IT AND SOMEHOW I GOT 1 WIRE OFF ON MY CAP SO IT WAS RUNNING RETARDED WELL THEN I GOT IT RUNNING PRETTY SMOOTH BUT IM KINDA CONFUSED ON THE TUNING ORDER LIKE DO I SET IAC THEN TPS THEN TIMING I NEED THE ORDER IN WHICH TO SET THEM AND THE CORRECT WAY TO SET THEM,CAUSE ITS RUNNING PRETTY SMOOTH BUT I CANT GET MY IDLE DOWN AND WHEN I SET THE TIMING I UNPLUG THE EST WIRE SET THE TIMING TO 6DGREES BEFORE TDC AND WHEN I PLUG THE EST WIRE BACK IN THE TIMING ADVANCES TO 10-12DEGREES BFORE TDC.ARGH! IM NEW AT THIS COMPUTER STUFF SOMEBODY PLEASE HELP. THANX

 

Go to Home page and click on Tech Articles. The procedures are there.

 

What he said :-)

Give that a whirl and let us know what happens.

If its way out of whack, dont be suprised if u have to play with the TPS/IAC a few times to get it where it needs to be.

later
Jeremy

 

The tech article is too vague. It doesn't say to adjust the auto in drive. If set to 450 in park, when put in drive it will die. A lot of TPS's are not adjustable. It should list which are and aren't adjustable. Also, the IAC motor pintle should be checked to see if it's clean. A dirty pintle could cause an un metered amount of air than can cause an improper minimum air rate throttle plate setting. It should also mention that the IAC is not adjustable. It is controlled by the ECM. The ECM "adjusts" it. I've seen a lot of posts that people seem think it's adjustable.

 

well i got the timing thing figured out i didnt reset the computer after setting the timing,but now i have a different problem when trying to set the minimum air rate i with the engine at operating temp, put the paper clip in the a and b terminals in the aldl ,turn the key on but dont start,wait 30-60 seconds, unplug iac,turn key off,take clip out of aldl,unplug est wire, start the engine,had girlfriend get in the car with the car started put the car in drive while i was turn the idle screw to obtain 450 rpm in drive,but the lowest i could get was 1100rpm in drive then when i turn the key off and plug est wire and iac back,disconnect negative battery cable for 60 seconds to clear codes then connect negative cable and start it idles at about 1400rpm everything is brand new all sensors,throttle body, injectors etc ,any kind of insight would be greatly appreciated. thanx, joe
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oh yeah and the timing is set steady at 6degrees btdc now and tps reads 0.54v if that helps anything.

 

What are you model specs?
This is what I do for my '88 IROCZ 5.7L TPI Auto
I added some of my own steps and modified others, so use at your own risk.
Equipment: DVOM & precision Tach, or Scanning Tool (not just a Code reader.)
Any time I reset the IAC I:

1. Turn engine on and set timing under the following conditions:
   • Normal operating temperature
   • A/C off
   • Transmission in neutral
   • Disconnect SET TIMING connector (Quick disconnect with tan/black wire) located in harness over the top of the HVAC housing, DO NOT disconnect 4 wire connector at distributor.
   • Set initial timing to car model's specifications.
   • Check the Timing in Drive, should not have moved.
2. Turn the engine off.
3. Remove the TB & IAC and clean with Seaform - reinstall the TB, but not the IAC.
   • Disassemble the IAC clean with Seafoam reassemble and adjust pintle to about 1" from the seat face to the pintle end, the pintle will reset in step 7.
   • Lube the IAC (even if it's new) and TB moving parts with TriFlow lubricant before installing.
     
4. Leave the Set Timing Connector disconnected.
5. Ground the diagnostic terminal, turn the ignition on, but do not start the engine.
6. Wait 45 seconds for the IAC to fully seat, then with the ignition still on disconnect the IAC connector.
7. Start the engine and allow the engine to go into "Closed Loop"; I wait until the primary fan has cycled at least once. A scan Tool will show when it's in closed loop
8. Remove ground from diagnostic terminal.
9. Adjust idle speed with precision Tach, or Scan Tool to specifications using throttle stop screw.
10. Turn ignition off and reconnect IAC connector.
11. Check and adjust TPS voltage if necessary, check it again after locking it down.
12. Start engine and check for proper idle operation.