high idle when warmed up?

Neelsonwheels

Neelsonwheels

Donating Member
Anybody have any idea why my truck will startup and idle at around 1000 rpms and run just fine,then once the engine is good and warm the idle will rise to around 1400 to 1500.
I was thinking vacuum leak and checked all that and all seems well there. I was also thinking possable intake leak when thing warm up maybe the leak shows itself and is causing the idle to climb?
Does this seem like an IAC issue?
Let me know what you think.
The motor is fresh and is in need of tuning but it is diffucult to find someont to tune the big stuff ecm and I am a computer idiot basically.
The truck is going in for a dizzy gear swap from standard to composite soon and if it is an intake issue I will address it at the same time. I need this straightened out before 10/2 as I plan on competing in a local car shows 100 foot drag competition.
Thanks in advance.
 
SYCLONE#1531

SYCLONE#1531

'MOFOFAST
Re: high idle when warmed up?

could be worn bushings in tb throttle shaft. When things warm up clearances will increase. I had the same issue with mine. Replaced it with a Profesional products 58mm tb and solved the problem.
a1000pump002.jpg
 
The Bronze

The Bronze

New member
Record a file using DM. We should see RPM, desired RPM, IAC pos, TPS, engine coolant, Battery voltage and MPH PIDS. also the A/C switch status. Report the results. All the above pids have a hand in idle control. Throw MAP in as well. A full cold to warm DM file would be best.

I want to see if the ECM is commanding the increased idle or trying to reduce it. We then go from there.

Mechanically, I would be checking for a free throttle cable and no vacuum leaks.
 
Neelsonwheels

Neelsonwheels

Donating Member
Re: high idle when warmed up?

thanks I will look into those things.
As far as files I am as before mentioned a complete failure at any ecm type stuff.
My truck is controlled by big stuff3. tranny and every thing.I will keep you posted.
Thanks again.
 
The Bronze

The Bronze

New member
Re: high idle when warmed up?

If nothing else, just jot down the cliff notes during the first moments cold running and after the idle has stabilized at it's higher idle. Make note of any fluxuating data while it is idling though.
 
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