Truck cranks and immediately shuts off

2016 SR5 5.7L V8 got home the other day from grocery store unloaded the truck and decided I was going to reposition truck.. hopped in truck starts and immediately shuts off.. after checking the battery, and crossing it off I have been left stumped.. I had just filled up on gas before heading home so we caught a sample and gas looks fine, another forum I had read mentioned removing the MAF sensor to see if it would start and still no luck.. I’m beginning to think it is an electrical or computer or theft mode issue? Truck will crank and then immediately shut off.. any help would be greatly appreciated

 

Crank and start and shut off or crank and then the starter falls off?

 

Crank an start and shut off.. rpm’s get up to 2k and come right back down

 

How did you check the fuel quality?

 

Did you check the battery voltage while it's cranking? I've had this happen when the battery is marginal.

Can you stop it from stalling if you press the accelerator?

 

I did check the voltage while cranking, seems a bit low to me at a 12.5.. I removed battery and brought to autozone was gonna just replaced it but their tester showed good battery.. so I brought home and charged for 30min on 12v 6amp charger still having same issue.. if it was the battery though, wouldn’t the truck not crank at all? After the crank the power should be distributed from alternator correct?

 

Fuel pump controller is bad. It’s above the left rear wheel you can see the 1 12mm nut holding it to the frame from the outside.

 

12.5 while cranking is fine. In fact, if you let the vehicle sit a few hours and go crank it, it can dip down to 11 while cranking and still be fine. Nominal voltage after resting is 12v.

Sounds like a fuel pump or fuel related to me. Is your truck a flex fuel, by chance?

 

I don’t think it is.. I considered that as well

 

Just went and tried to crank for the first time today and truck won’t fully crank now? Where as for the passed two days it has cranked and shutoff

 

I'm not a mechanic but as others have suggested it certainly seems like a fuel delivery issue.
You were getting minimal fuel that turned over the engine, now you aren't getting any.....


Back in the good old days, we could drip a little gas into the carburetor..

Welcome to the forum..

 

Appreciate the responses

 

Did you happen to be using remote start prior to this happening?

 

No I don’t have one

 

well then I got nothing! Sorry brother, good luck

 

Even if you told me the battery is 6 months old I wouls still replace it and wholly eliminate that "easy fix" first. Then move to the fuel system.

 

Havent had any fuel pump issues with my toyotas so I can speak on them, but when testing my chevys fuel delivery one thing I would do is just unhook the fuel filter and see if its pumping.

 

So after towing to the dealership.. they run a diagnostic to find that the immobilizer ECM is causing an error.. they want to do a full replacement on that ECM for 2k.. talked to the tech about trying to reset or reprogram that ecm.. they did so and still no luck.. has anyone ever had issues with their keys possibly causing this issue? Like a theft mode issue? When I went to re position the truck the day that is happened I grabbed my wife’s set of keys (which I don’t normally do).. I know that the keys sent out a specific code set.. I’m just trying to weigh out options other than replacing the ecm right away.. does anyone think that wiping the keys would be a valueable option? And if it was they keys would their be a diagnostic code that the tech would see, or does the truck not provide that?

 

Man, that sucks. I've heard of that happening on other vehicles and had the suggestion running in the back of my head, bu every other time I suggested the immobilizer as being problematic, it turned out to be a fuel pump. Go figure.

I've seen it happen on a vehicle that was locked with one key, then unlocked with a different key, but it was resolved by locking and unlocking with the original key a few times. Or maybe locking with the offending key, unlocking with the original key, turning the key in the ignition while rubbing the dash and whispering sweet nothings into the air vents while thinking positive thoughts of a raucous cacophony of V8 rumble... or some sort of witchery. I don't remember exactly, but something worked out.

Perhaps try programming a new key to the current ECM? It would be cheaper than an ECM replacement.

 

Any update on where this ended up? Hopefully wasn't too bad.