Understanding Key Fob and Security System -- Technicians?

Here we go. Sometimes I leave my key in the ignition overnight. (Rural area and a Doberman that loves to ride in my truck). So I go out the next morning and start the engine. It will run for a few seconds, and then dies when I try to back out. Solution: Remove the key for about 10 seconds, holding it far away from the steering column. Usually it will start right up and run without interuption.

Weird part: Other nights when I leave the key in the igniton overnight, the next morning it will start right up and stay running without cutting out.
Question: Why does the engine cut out sometimes, and then other times it will run without a hitch? Completely illogical.
Thanks in advance. Hot Ajaxx

 

What you describe is not how the immobilizer works. (Security system)
The immobilizer will let the truck crank, but never start.

Your problem sounds like a bad fuel pump resistor. When you first start your truck, the resistor is bypassed. Once it has run about 10 seconds it then switches to the resistor.

 

Leaving key in truck is how it gets stolen

Vehicles locked go into sleep mode reducing power to electrics to save battery.

not doing that usually messes with things

 

I'm with @TnShooter, I'd suspect a fuel system issue or fuel pump relay that isn't switching properly between high and low speed.
Another possibility the throttle body is getting a bit dirty and causing cold idle to be a bit too low.

My keys stay in mine all the time at home and I've never had an issue with it doing that.

 

Basically if it starts, thats it, the immobilizer has done its job and won't stop the truck again. So if the security light flashes and turns off, the immobilizer is fine.

This sounds like fuel to me as well. It's a pain to find a fuel gauge for these trucks, so you may be best off taking it to a shop as this sounds like an issue that can leave you stranded.

 

My Doberman likes the truck too much for somebody to steal it. She likes those rides.

 

Theft isn't the issue

 

The immobilizer cuts power to the fuel pump completely. crank all you want, but it will never start if the immobilizer is doing its job.

sounds like you have a different issue. the fuel pump relay that switches from low to high is down by the battery. unplug it and see what it does. start there to investigate, as that is free and easy.

also, take the key out completely, to see if leaving the key overnight has something to do with the issue.

 

Sounds like you and Tennessee Shooter have the goods on this. Thanks.

 

Thank you.

 

Thank these guys, they helped me out last year.
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