2012 Tahoe 5.3L flex fuel - Will Not Start

[Billeickmann]

My Tahoe has 59,000 miles and has been great. It has new spark plugs and wires. Newer battery and starter. New air filter and MAF sensor. Lately it has stumbled on cold start, but runs great after a 60 second warm up. Today it will not start at all. It is warm today in Michigan at 60 degrees. Last ran yesterday. I tried starting fluid. I tried disconnecting the MAF sensor for "limp" mode. It cranks great, but only slight signs of ignition. The check engine light is on. My code reader shows "P0113 - Intake Air Temperature Sensor 1 Circuit High". Code shows the same, twice on my reader. I had some ignition problems with the truck last March, but the above listed changes worked until today. I just watched a you tube video and the tech suggested the wiring or computer are the most likely suspects. Any help is really appreciated. I don't even know where the IAT sensor or computer live. Thanks in advance. Bill

 

[Doubeleive]

if fuel pressure checks out (you should have 50-65psi key on, and 44-50 running) then next suspect would be maf (due to code), otherwise crank position sensor, injector harness
other important things to check: battery cables

 

[Billeickmann]

OK. Grounds cleaned. Codes cleared. MAF cleaned. Very hard to start, but when started, coed reader said OL fault. Rough idle smoothed out. Fuel pressure 42.5 to 43.5. Went to CL. Code reader says 0172 and 0175. System too rich bank 1 and 2. I could not find the value for the ethanol amount.

 

[Billeickmann]

Forgot to add. It runs like a clock when warmer up.

 

[swathdiver]

Ethanol content may be off which tricks the computer into putting too much fuel through the injectors.

 

[alpha_omega]

Are your connections at the battery and starter nice and tight?

Did you check the wiring harness for the MAF to ensure none of the pins/wires are bent or loose?

 

[Fless]

Is this a Flex Fuel vehicle?

What type of fuel (gas or E85) is in the tank?

Tried clear flood mode when cold starting?

 

[Billeickmann]

1 YES Flex fuel 5.3

2 Costco regular in the tank. Truck has never had E85. Added SEAFOAM today.

3 YES She needed a little pump and pedal to start. Would not start without a little gas pedal.

Still can not find the value for the ethanol percentage. What should I look for on the code reader?

 

[Billeickmann]

YES Battery and starter connections are clean and tight.

YES MAF connections are good.

 

[iamdub]

YES Battery and starter connections are clean and tight.

YES MAF connections are good.

Check the harness connections on the throttle body. Maybe unplug, blow them with compressed air, plug and unplug it a few times, push the wires into the connector to ensure they're seated, etc. Clear the code(s) then start it.

If it definitely seems temperature-related, use a hair dryer or heat gun to warm the PCM to test for faulty solder joint(s). Maybe reseat the harness connectors on the PCM.

Just try one thing at a time so you don't bury the root problem.