TPITuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
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Well, I used the tech page writeup for the IAC adjustment and unfortunately followed it to a T. I believe there is supposed to be a 'turn ignition key from on to off' prior to unplugging the IAC............yes? Well, I didn't turn it off, and then upon trying to start the motor it wouldn't, so I went back through the sequence (key on but motor off for 30 seconds, then key off, unplug IAC, start motor) and it started. Code was flashing, expected that.
So next weird issue. After putting the trans in Drive (wife in vehicle holding brakes), lowering the idle, couldn't get it below 550 before the throttle return 'bottomed out' and was no longer adjusting anything. Put the screw just barely against the throttle return, shut off the motor, took out the U shaped paper clip (again not mentioned at what stage to remove this, assumed it was after you shut motor off............was I wrong?), plugged back in the IAC and started it up.
TPS was now at .35 volts............but the motor was idling very smooth. Adjusted the TPS up to .54, now it starts to idle up and down (hunting).............and idling at 950 rpm in park.
Prior to doing this, I cleaned the IAC as per the instructions........went very well.
Your sequence was a little off.
Here are the instructions from the Haynes manual:[list=1][*]With IAC valve connected, ground the terminal B on the ALDL (ignition off)[*]Turn ignition ON but do not start the engine. Wait 30 seconds (this allows time to close the IAC plunger)[*]With ignition ON, disconnect the IAC electrical connector.[*]Remove the ground jumper from the ALDL.[*]Start the engine (you may need to either step on the accelerator some to let air in the engine since the IAC is completely closed, or screw in the idle stop screw)(this is why the engine would not start the first time)[*]Run the engine until it reaches normal operating temperature[*]Adjust the idle stop screw to obtain either 400 RPM in Drive or 450 RPM with manual transmission.[*]Turn ignition OFF and reconnect the IAC[*]Adjust the TPS to 0.54 volts +-0.075 volts[*]Start engine and check for proper idle.[/list=1]
Remember to reset the code. Also remember that when setting the minimum idle speed it is somewhat important that no accessories are running. That includes the cooling fans too. This will remove any load from the engine.
Originally posted by Ozzy88GTA Your sequence was a little off.
Here are the instructions from the Haynes manual:[list=1][*]With IAC valve connected, ground the terminal B on the ALDL (ignition off)[*]Turn ignition ON but do not start the engine. Wait 30 seconds (this allows time to close the IAC plunger)[*]With ignition ON, disconnect the IAC electrical connector.[*]Remove the ground jumper from the ALDL.[*]Start the engine (you may need to either step on the accelerator some to let air in the engine since the IAC is completely closed, or screw in the idle stop screw)(this is why the engine would not start the first time)[*]Run the engine until it reaches normal operating temperature[*]Adjust the idle stop screw to obtain either 400 RPM in Drive or 450 RPM with manual transmission.[*]Turn ignition OFF and reconnect the IAC[*]Adjust the TPS to 0.54 volts +-0.075 volts[*]Start engine and check for proper idle.[/list=1]
Remember to reset the code. Also remember that when setting the minimum idle speed it is somewhat important that no accessories are running. That includes the cooling fans too. This will remove any load from the engine.
Good luck,
Ozzy
Thank you very much...............that did the trick. I was using the tech article one from the main tech page and it had a couple of steps not spelled out...................did the job as you described it and no more problem. Appreciate the post.
