Increasing Idle as car warms up

[QBRacing74]

Started the truck for the first time in ages the other day to show a family member what it sounds like with the exhaust on. Thought I would let it run for a little bit to get some heat in it as well.

Car started fine and ran fine BUT as it slowly warmed up the idle increased from 1100ish to over 2000rpm with no throttle input (and I couldnt find any air leeks)

I was luck I had the laptop running a couple of logs at the time.

The IAT was reading 50+ as there was no airfilter on and it was pretty warm under the hood. I turned it off, checked the temps of the headers and most were about 130 degrees (2 & 7 were only about 105-110).

Any ideas on where to start?

I see for some reason that base advance was at 40 degrees and appeared to be switching on and off so I suspect it has to do with that. What triggers that in that fashion?

[dhoagland]

Your going to be asked to post your tune so it can be looked at...

Are you saying you didn't hit the throttle a few times?
In the log I looked at the throttle position was raised at the peaks in the rpm.

[ryan_axberg]

you should log you iac position, stit and ltit

[QBRacing74]

dhoagland: I did give it a couple of blips but after than it was idling and thats when the rpm increased and throttle was a 0% (or close to).

Ryan_axberg: I have added them now . thanks

Added the tune file now to post 1 (thought I had but I had added 2 logs), my bad

[QBRacing74]

So I just went an run another check after adding IAC POSN, LTIT and STIT.

• LTIT didnt appear to do anything at all for the 6 mins just sat on 0
• STIT dropped if I revved the engine at all
• Idle air position started about 220 and dropped to about 20 after 50 seconds. During this time idle was about 1000rpm and had a lope to it.

After this the IAC POSN sat at 0 unless I gave it a blip on go fast pedal and the idle increased to a pretty constant 1400 rpm.

What is concerning me is the high voltage reading of the 02 sensors.
In the back of my head thats a "rich AF" reading and considering it sounds like a tornado trying to suck small animals into the inlet it must be hell rich. I only say this as after the 6 minute run this time the headers had a nice red sheen to them

Think I should go get a air/fuel sensor to throw on the exhaust before i start it up again.

[ryan_axberg]

your short term and long term fuel trims aren't doing anything, you have it in open loop. If you enable stft it will be able to correct fueling. Also you should try closing off your throttle blade some to get the idle down. Have you checked for any vaccum leaks? It is running so low of timing also becaus it is trying to reduce the idle speed. It never hurts to have a wideband in there, but you will be fine with just stock o2 sensors at idle and part throttle.

[dhoagland]

Are you intentionally not wanting to go into closed loop? Closed loop enable has the coolant temp maxed out.

Also your PE is set to 1, is that on purpose? I have never seen that done...
(I know that has nothing to do with your idle)

Keep us posted

[QBRacing74]

@ryan and @dhoag
To be honest the tuner I plan to use flashed me an SD tune (from a similar car/engine combo) so I could move it around and get it on and off trailers etc. At that stage I didn't have doors and windows installed (still dont) so I haven't gone back to finish the tune as he wont do it without them (fair enough).

I'm a beginner tuner but understand what you are talking about. I've just compared the original tune with the one he did and can see both of your points (I just dont know why he did it). I'll try changing them back to original, make a note for him of what I've done and go from there I guess.

Q

[dhoagland]

I'm a beginner too...
I'm enjoying following this, looking at your logs and tunes trying to find things... I'm real interested in seeing what effects the stock tune has on your situation

[INSANEREINDEER]

Throttle blade is open too much or there is a vacuum leak allowing to much air in. The IACV is maxed out and can't do anymore to minimize airflow.

If your tuner set your PE tables all to 1, you should find a new one that wants to do it correctly. Don't try to rev it at all like this.