Idles high after being in gear.

[1998_K1500_Sub]

Guys, just FYI, after tonight I'll be away until perhaps Thursday and won't be able to contribute.

Finding a solution to this problem is high on my list and, if it isn't ironed-out today, I look forward learning about what's been accomplished when I return on Thursday.

I'll still be active here through the evening.

 

[PlayingWithTBI]

Guys, just FYI, after tonight I'll be away until perhaps Thursday and won't be able to contribute.

Hope it's for pleasure and not work, ha ha.

Finding a solution to this problem is high on my list and, if it isn't ironed-out today, I look forward learning about what's been accomplished when I return on Thursday.

I'll be around off and on but, I'm pretty much running out of suggestions. Maybe wait until @BigRedOne gets his ALDL scanner set up and get some better data from logging?

 

[BigRedOne]

Really appreciate all the help and info guys.

Update: going to have to wait and see how the aldl cable and software work. Tried to set idle in drive with my friends help and that scanner is not helping. I tried slowly increasing the idle and watched the counts come down but it got to a place that it was really loading up and killed the engine. Restarted and it was reving to 1700rpms in park with 0 counts on iac. I need to have proper info and real data to do this right. Still feeling like the prom is giving false data or no datA. Not going to pull the trigger on a new one until I've exhausted all diagnostic option. Hope you guys stay along for the ride with me.
Thanx for ridin this far.

 

[1998_K1500_Sub]

Tried to set idle in drive with my friends help and that scanner is not helping. I tried slowly increasing the idle and watched the counts come down but it got to a place that it was really loading up and killed the engine.

Please be certain you're following the instructions diligently, in particular that the ECU is not in "10k" aka "Special Mode" (see my earlier post) but rather "open mode". See the reference to "open mode" in the instructions on pg. 4-17, and the explanation of the modes on pgs. 13-1 to 13-2 and their effect on the engine.

Too, the charts on pg. 4-44 state the adjustments are to be made "open loop"... and I don't know (yet) exactly what that means. I doubt they mean "open mode", that appears to be something else.

And yes, I think I know what's meant by "open loop" on pg. 4-44, but I'm not certain I know. Until this "open loop" requirement is satisfied during the adjustment, we may be pi$$ing into the wind.

This is going to be a great story to talk about, once the problem's solved.

 

[Donald Mitchell]

I know how these things tend to snowball, and I tend to look for a simple cause for the effect, So pardon me if this has already been looked into. My thought is it might just be a mechanical issue such as a throttle blade slightly bent and sticking. Hell, at least it shouldn't take long to check.

 

[BigRedOne]

Please be certain you're following the instructions diligently, in particular that the ECU is not in "10k" aka "Special Mode" (see my earlier post) but rather "open mode". See the reference to "open mode" in the instructions on pg. 4-17, and the explanation of the modes on pgs. 13-1 to 13-2 and their effect on the engine.

Too, the charts on pg. 4-44 state the adjustments are to be made "open loop"... and I don't know (yet) exactly what that means. I doubt they mean "open mode", that appears to be something else.

And yes, I think I know what's meant by "open loop" on pg. 4-44, but I'm not certain I know. Until this "open loop" requirement is satisfied during the adjustment, we may be pi$$ing into the wind.

This is going to be a great story to talk about, once the problem's solved.

Thats the problem with the scanner I borrowed. No way to turn off the 10k resister. The scanner says I'm in closed loop which in park at idle should be open loop via that service manual. Don't know how or if the scanner is translating that correctly. Gotta wait for the cable I guess. If it is actually in closed loop what would cause that? Prom?

 

[BigRedOne]

Please be certain you're following the instructions diligently, in particular that the ECU is not in "10k" aka "Special Mode" (see my earlier post) but rather "open mode". See the reference to "open mode" in the instructions on pg. 4-17, and the explanation of the modes on pgs. 13-1 to 13-2 and their effect on the engine.

Too, the charts on pg. 4-44 state the adjustments are to be made "open loop"... and I don't know (yet) exactly what that means. I doubt they mean "open mode", that appears to be something else.

And yes, I think I know what's meant by "open loop" on pg. 4-44, but I'm not certain I know. Until this "open loop" requirement is satisfied during the adjustment, we may be pi$$ing into the wind.

This is going to be a great story to talk about, once the problem's

Please be certain you're following the instructions diligently, in particular that the ECU is not in "10k" aka "Special Mode" (see my earlier post) but rather "open mode". See the reference to "open mode" in the instructions on pg. 4-17, and the explanation of the modes on pgs. 13-1 to 13-2 and their effect on the engine.

Too, the charts on pg. 4-44 state the adjustments are to be made "open loop"... and I don't know (yet) exactly what that means. I doubt they mean "open mode", that appears to be something else.

And yes, I think I know what's meant by "open loop" on pg. 4-44, but I'm not certain I know. Until this "open loop" requirement is satisfied during the adjustment, we may be pi$$ing into the wind.

This is going to be a great story to talk about, once the problem's solved.

As far as " open loop" and closed loop. Open loop ignores the O2 sensor feedback for fueling it just follows preset ecu instructions and closed loop relies on all the sensors.

 

[1998_K1500_Sub]

As far as " open loop" and closed loop. Open loop ignores the O2 sensor feedback for fueling it just follows preset ecu instructions and closed loop relies on all the sensors.

Yes… but I can’t assume the manual’s technical writer didn’t get confused between the use of “mode” and “loop” when writing those sections

Too, the manual gives no instruction about how to force “open loop” on pg. 4-44, so I find it possibly subject to misinterpretation.

But follow them as diligently as possible(!)

 

[PlayingWithTBI]

Thats the problem with the scanner I borrowed. No way to turn off the 10k resister.

There may be a jumper on the ALDL connector, at least my ALDL/USB cable for my laptop has one which can jump A&B, add 10K Ohms, or go straight through. YMMV

Here's a quote from the manufacturer of my cable. The 10K resistor goes across pins A&B

"Older 160 baud ALDL cars (such as early TPI's like GM 1227165 ECM, 1986-89 5.0 and 5.7 V8's) will require a 10Kohm resistor to be plugged in between pins A and B on the 12 pin ALDL connector in order to put the car into "ALDL mode" and have the serial data start flowing. The 10Kohm resistor is built into our cable and is enabled with a simple jumper setting."

 

[Schurkey]

Want open-loop? Unplug the O2 sensor wire.