Starts and then shuts off

I have a 2012 Tundra with the 5.7 in it. Fuel pump went bad so I replaced it, now the truck gets fuel again.

Only thing is, now it starts, runs for about 4 seconds and shuts off. If I try to restart it again, it will just crank over. If I let it sit for a few minutes, it will run for the 4 seconds, shut off and so on and so forth.

Thinking the fuel pump control module behind the tank could be the issue? If there a way to check that without spending another $400 on a part I might not need?

 

Official welcome for your first post. Hope you can resolve the fuel issue.

 

Welcome
How's the battery?? Battery dying will make the truck do weird things.. Have you tried giving it gas until it idles correctly?

 

Thanks for the welcome!

Battery is brand new, checked all the fuses and relays and they seem to be working fine. Noticed the longer I let it sit without starting, the better it starts up.

I tried to pump the accelerator while it was running and it would shoot up in rpm's as it normally should, then die right back out.

Could air in the fuel lines be an issue as well for this?

 

Alternator is good too, everything not fuel related is working as it should be

Just checked a few more things, great fuel pressure, new pump works awesome, but then starts up, runs and dies 5 seconds afterwards.

Maybe its a line leaking somewhere? Although I smell no gas coming out

 

Maybe try keeping an idle for about 30 minutes?? I've had some issues sort of similar... I've sat and watched the idle as soon as it would drop below 500RPM I would give it gas to 1.5 to 2RPM for a few seconds and slowly lay off the gas... Maybe a learning curve for the ECU to learn....

I know this may be a stretch, but is there fuel in the tank?? More than a 1/4 tank. My 07 gauge is starting to stick again.. I got stranded with a 1/4 tank of gas a couple days ago, but I was empty 1 gal jerry can and a mile huff got me moving.. Would also start for a few seconds then die, or I would put it in gear and would die.

 

Thats the thing, I cant keep it idling, it wants to shut down right after it hits the idling rpm's. I try to give it gas to ramp the rpm's up but there is no response. And theres half a tank in it, I removed the gas, cleaned the tank and replaced with new gas and still having the same issue. Tried putting it into gear and it had he same response; stalled out with no success.

I keep on tinkering with it, could it be a problem with the Mass Air Flow Sensor going bad/being dirty and not getting the correct ratio? I ran an OBD2 check and no codes popped up.

Going to try and clean the MAFS in the morning and see if it makes a difference

 

A few weeks back someone had very similar issues. Had replaced the fuel pump truck still wouldn’t run. I believe he ended up replacing the fuel pump ecu on the back frame rail and that fixed it.

It almost sounds like yours is delivering enough fuel for the cold start and then it quits. Reasons why it only runs a few seconds

 

What are the last two mechanical things you did to the truck?

Do you have an aftermarket anti-theft system?

 

Im about to go and buy a new pump ecu because I think thats the root issue. Just cleaned the MAF sensor with no luck, and I dont want to burn the new pump out. Is there a way to bypass the fuel pump ecu to check if thats it?

Last two mechanical things were the water pump and oil changes, never had any issues until now. Water pump was 2 years ago. And theres no after market anti theft installed

 

My 08 did something very similar to this one in a while. I figured out it only happened when i had the key in the ignition for an extended period of time (several minutes) before trying to start the engine.

 

Battery in the FOB going bad and therefore not able to properly complete the "handshake" with the truck's anti-theft system?

 

Do you mean like leaving key in ignition but in off position for long periods of time? My 09 has been doing the same thing as Jhiginson every so often since the fall and I leave my key in ignition all the time at home. I wonder??

 

Sorry just saw this, give me a few minutes and I will see if there is a way to “jump” the fuel pump ecu briefly to test and see if the truck runs correctly

 

+ me too. Handful of times. Just got used to not leaving the key in the ignition (off)

 

Yes. That is what I mean. This issue only ever happened when I stopped at a fast food place, then parked to eat my food. I would turn the engine off, leave the key in the ignition and eat my food and maybe watch some YouTube. When I went to start the engine again, it would fire up, run for a second, then die. That would happen over and over (one time it never started but just kept cranking until I turned the key back) until I pulled the key out of the ignition, locked the truck, unlocked it, got back in, and tried to start it again. I also called my brother in the meantime, so I don't know if there is a certain amount of time that has to pass or what..

I think it has something to do with the little security chip inside the key. Might be a security feature that prevents theft of your truck if you accidentally leave your keys in the ignition or something.. I'm not sure.

But ever since I stopped leaving my key in the ignition, I haven't had this issue.

 

Ok thanks. Im going to start taking key out alll the time now and see if it goes away.

 

Any luck?

 

Im gonna give it some time. Its been 1 day.

 

So its been a month since I started taking the key out. Its only acted up once but only because I forgot and left the key in it one time. I did as Kur said and pulled the key out of the ignition, locked the truck, unlocked it,got back in, and tried to start it again and it fired right away. What a simple thing that could have ended up costing in unnecessary repairs and dealership visits. I hope this helps other people that are having similar issues. I will report back if it starts acting up again. Thanks Kur for the suggestion!

 

Reset the security ecu and it’s recognition of the key.

Nice to know that fixed it. Makes you think there is a timer in the truck to see and verify the key after putting it in the ignition.

 

Ya something like that

 

Any update to your situation on this? (The leaving the key in (off position) and the truck not starting)

I have a 2019 platinum. And it’s only happened twice in the last 3 weeks. The only commonality I can see so far (since it only happened twice) is I left the key in the ignition (off position). Once while getting gas and a second time while waiting for my wife for 5 minutes while she was getting some groceries)

 

Something similar with my 07. You start the truck, it starts right up, rpm's come up to 1500-2000 like it should and then it immediately dies. You try again, same thing happens. It's like someone is turning off the key. You wait 5 minutes it starts right up and you are good to go. Like it never happened. At first I thought it was the FP but I've had no issues with normal driving. But now I wonder if maybe there is debris in the gas tank that's maybe floating around and clogs the pump. I don't know. The problem happens so infrequently, you could chase after a cure but you don't even know what the problem is. I'm just going to run it until I can really identify the problem and fix it from there.