If I'm interpreting your situation correctly... Your SUV WILL Start... However it STILL Cranks Over a Long Time before Starting? If so... indicate it in your next reply and consider these issues relating to "What Can Cause Hard Starts?" as Food for Thought:
Hard Starts can have MANY Causes and Origins... Here are The Most Likely:
In Order for any 4 Cycle Engine that follows the "Intake, Compression, Ignition (Power Stroke) Exhaust" Pattern, THESE Conditions MUST be Present:
(1) Air (In The Proper, Unobstructed Amount able to reach 14.7 Parts to 1 Part Fuel by Volume)
(2) Fuel (Clean, Proper Octane...and Neither Too MUCH Nor Too Little)
(3) Compression (In the GM Atlas LL8 Engine ...Approx. 10 to 1 Compression Ratio)
(4) Spark (Powerful enough to Ignite the Compressed Air/Fuel at 10 Xs Sea Level Atmospheres)
Because of the extreme variability of Engine Designs... the "Spark" as being most critical is not specified... but the TIMING of the SPARK is quite Critical.... If the Spark Ignites the Fuel too SOON as the Piston rises to compress the Fuel and AIR... the Power would not only be Weak... but happening Prematurely and actually prevent the Piston from rising to complete its Power Cycle.
The TIMING of the Spark Events must be varied by the PCM to know when to "Light The Fire" in each Cylinder just a little before each Piston rises to meet at Top Dead Center (TDC) in its Rotational Arc. By doing it this way, ALL of the Fuel and Air have enough time to COMPLETELY Burn... ,and extract every last ounce of Power available each and every time the Power Stroke pushes those Pistons back down and transferring the energy through the Connecting Rods and into the Journals on the Crankshaft to achieve Rotational Energy and Torque.
So... What Happens to Prevent these Events from working Normally? Here is a List of What can Go Sideways and Cause "Hard Cranking Starts" to Occur:
(1) A Weak or Dead Battery (The PCM Controlled Systems are VERY Touchy about Low VDC).
(2) Old, Incorrect Plug Designs (Too Hot or Too Cold) Damaged, or Poorly Gapped Spark Plugs.
(3) A Clogged Air Filter.
(4) Worn Pistons, Trapped or Worn Pistons Rings, Worn Out Cylinders (Low Compression).
(5) Weak or Inoperative Electric Fuel Pump, Clogged Fuel Filter (Low or "0" Fuel Pressure).
(6) Inoperative or Damaged Sensors: ACC, TPS, MAF, IAT, O2, MAP, CPAS, CPS, CKP.
(7) Shorts or Broken Harness Wires and Independent Wiring Connections, or Corroded PDC Fuse Block.
(8) Poor Electrical Ground Connections.
(9) Burned Fuses or Bad Relays
(10) Failed PCM-ECM... It is Rare ...But it Has Happened on Occasion.
These ...and perhaps a few other issues can work either singly... or in concert with each other in a bewildering variety of FUBARs to either Make it Hard to Start the Engine... or Prevent the Engine from Starting, Running and doing so with Nominal Performance