Strange electrical issue

[1998_K1500_Sub]

If you're confused by the YouTube Video, do this:

Hook up a scan tool. Leave everything connected on the engine as it should be... no "jumpers" on the ALDL or anything.

Watch the IAC values. Note the value NOW, write it down, post it back here. Then...

While watching the IAC values, adjust the idle screw slowly. You should see the IAC values respond / change as the ECU moves the pintle, trying to maintain the engine RPM.

Twiddle the idle screw until the IAC values are at their TARGET / TYPICAL VALUE as provided by the factory service manual (example: 18, in my post above).

See how the motor idles... surge / lope / die, etc.

This is a simplistic way of adjusting the idle screw.

 

[bogus]

If you're confused, do this:

Hook up a scan tool.
Watch the IAC values,
While watching, adjust the idle screw. You should see the IAC values change as the ECU tries to maintain the engine RPM.
Twiddle the idle screw until the IAC values are at their TARGET as provided by the factory service manual (example: 18, in my post above).

See how the motor idles, then... surge / lope / die, etc.

Okay. Which scan tool could I use for obd1? Do I have to get an obd1 adapter or is this just directly plugged into the IAC type deal?

 

[1998_K1500_Sub]

Okay. Which scan tool could I use for obd1? Do I have to get an obd1 adapter or is this just directly plugged into the IAC type deal?

It'll plug right into the ALDL connector under the dash.

I use Rinda's DIACOM on OBD1, but it's an OLD tool. I bought it back around 2001.

You need a scan tool, you're pi$$ing in the wind without it. Look through GMT400 or post a new thread asking "What scan tool for OBD1"?

 

[bogus]

It'll plug right into the ALDL connector under the dash.

I use DIACOM, but it's an OLD tool.

You need a scan tool, your pi$$ing in the wind without it.

Gotcha, thank you

 

[1998_K1500_Sub]

I found the base idle chart on the manuals but no direction on how to adjust the factory screw.

Of course, I'm an idiot. You're not supposed to adjust that screw, it shouldn't need adjustment, so they don't tell you how to do so in the manual.

OK, do as I suggested earlier. Twiddle the screw until you get the IAC count to be where the manual says it should be. Let's see how it runs, then.

 

[bogus]

Of course, I'm an idiot. You're not supposed to adjust that screw, it shouldn't need adjustment, so they don't tell you how to do so in the manual.

OK, do as I suggested earlier. Twiddle the screw until you get the IAC count to be where the manual says it should be. Let's see how it runs, then.

Okay I'll have to buy a scanner and an adapter first lmao thank you so much for your help I'll make sure to check in with you once I got it adjusted

 

[1998_K1500_Sub]

Okay I'll have to buy a scanner and an adapter first lmao thank you so much for your help I'll make sure to check in with you once I got it adjusted

Great

I think you've about got this problem licked.