I am checking out all of the sensors and or relays that feed the brain of
this thing. After 120,000 miles, I want to make sure everything is reading
what it should and that the computer isn't compensating or "just inside
range" on some of the values. Just a bug I got on and wanted to follow
through. Yes, it does have the TBI and yes, it is a 4x4, so that means it
has the K designation. Are you sure there is not an IAT? What would replace
it or what other readings does the brain pull from?
in this instance, the 4x4 is not the "K" he was looking for, it is the VIN
code for the 5.7 TBI engine. IAT is Intake Air Temp, right? 96+ Vortec's
have them, TBI motors do not.
I'd say since the TBI is a MAP based system, air temp isn't as important as
in a MAF based system.
On throttle body injections like the one on your truck, something called
"speed density" is used. The computer is setup to determine fuel deliver
based on MAP (manifold absolute pressure--vacuum), TPS(throttle position
sensor), CTS (coolant temp sensor), and Oxygen Sensosor. With speed
density, I'm assuming, GM figured out how to deliver fuel based on factors
without IAT. It's all in the engineering. If "there is more than one way
to skin a cat" there is "more than one way to figure out how to inject fuel
into an engine and make it run".
On some vehicles I've seen where IAT is subtle input for fuel delivery, and
on other vehicles I've seen where it is a critical input for determining
fuel delivery. For example, in some foreign cars with early TBI injection,
the Oxygen sensor was a subtle input, where as long as I can remember oxygen
sensors in GM's have always been a crucial input for fuel delivery....
So long story short, to answer your question, NO would be the answer to
anything "similar to IAT".
Is this more clear now????
What wasn't clear?
YOU HAVE NO IAT OR MAF SENSOR ON YOUR TRUCK.
You have a MAP, TPS, CTS and O2 sensor-controlled engine. No mass airflow,
no intake air temp, no fancy schmancy Vortec controls.
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