2008 tacoma v6 cranks but wont start

so I have a 2008 Tacoma 4.0l v6. occasionally when its hot it will not start, the truck will crank and crank but will not turn over. the otherday when I was driving home from work I stopped to get gas a few blocks from my house and it wouldn't restart after I filled up. I walked home and came back a few hours later when it cooled down outside and it started first try. when the temperature outside isn't too hot it doesn't really act up and im able to drive it around. today my truck has been sitting outside all day in the hot sun and when I tried to start it it wouldn't start I will wait a few hours and when it cools down outside it should start fine. any ideas as to what is acting up on my truck or things I can check??

 

anyone have any ideas why my truck does this sometimes??

 

battery?

heat kills them. how old is it? take a voltmeter to it.

 

If its cranking over, its not the battery or alternator or starter. So your left with sparkplugs, fuel pump, or a computer problem. Could also be bad fuel I suppose so maybe run some dry gas through it. Spark plugs are easy/cheap to replace for a second possible fix. Fuel pump and computer problems will be more pricey and difficult to diagnose.

 

Get a Ford or a Dodge

 

Thank for the helpful reply, fop.

To the OP:

It's one of three things: Fire, fuel, air. You've got cranking, and to get it hot you had to have it running, so it isn't something physically broken.

Sounds to me like something specific to the temp or conditions at the time: Think vapor lock, or maybe a tube heated up to the point it expanded and restricted interior air or fuel flow. Some condition that is exacerbated by temperature.

 

Sounds like maybe your fuel pump?

 

The battery seems to be fine. I was thinking fuel pump possibly or something with the ignition, spark. I changed the plugs awhile back so they should be fine. How can I check the fuel pump? Do they regularly go bad?

 

Not regularly go bad but could have only way to check is by pulling the gas tank out and taking a look at it not sure how exactly to test it

 

I'm going to guess Engine Coolant Temp sensor or crankshaft sensor.

 

Ok, would it fail intermittently like that tho? Is there a fuel purge under the hood where I can check for fuel when it won't start?

 

I read coolant temp sensor as well. It can't be too expensive, might try there and then crank sensor or fuel pump.

 

$20 and $80

 

I wouldn't think so kinda seems like a sensor is out somewhere with a bad ground or a short in your fuel system not allowing the fuel pump to work properly

 

Anyone you know got a scanner ?

 

Not sure a scanner will help if it's not throwing a code

 

I have a scanner but there's no codes. The other day when it wouldn't start I hooked the scanner up and it couldn't connect to the ecu

 

Hmmm...it wouldn't start and you couldn't connect? That sounds an awful lot like a ground issue...it would explain why the plugs aren't firing right and the ecu isn't responding.

However, hunting down a ground that only grounds when the truck is hot sounds like a cast-iron bitch

 

Ya its a pretty weird situation. Any ideas which grounds I could check?

 

The answers to all of your questions are contained within the following link: http://www.customtacos.com/tech.old/files/05FSM/

It is difficult to diagnose problems like this over the interwebz. Check the basics. Battery voltage above 12V? Are you getting spark? Are you getting fuel? Next time it won't start try unplugging your maf sensor and see if it starts, then temp sensor, crank sensor, etc. If it starts when you unplug one of those sensors you found your problem. The ECU will start the engine in "limp" mode with the connector undone, but if it is connected to a bad sensor often times it will not start.
http://www.customtacos.com/tech.old.../06toyrm/06toypdf/06rmsrc/rm2006ta/005006.pdf
Difficult to start with warm engine: