2008 tacoma v6 cranks but wont start

That 5V circuit is shorted, causing the ECU to shut down to protect itself. Look on page ES-378 (page 22 of 32 of the PDF) for a picture of the connector you need to unplug. http://www.customtacos.com/tech.old...06toyrm/06toypdf/06rmsrc/rm2006ta/0050058.pdf It's hard to read through all of this crap, but it is possible to decipher it and fix your truck with about half an hour of your time if you'd just do it. Nobody cares about your truck more than you.

 

Shit. There is no reason why it shouldn't not read the computer in the truck. It can't be your coolant sensor because it moe then likely still start. It would just run like shit. Unless the coolant sensor is dead entirely. The coolant sensor tells the computer what temperature your coolant is so the ECM can make fuel enrichment or fuel removal adjustments as necessary. However, if the issue is at heat soak that would indicate to me that either the sensor freaks out and dies aftet you turn the vehicle off and attempt to turn it back on, or your fuel pump is overheating and refusing to turn back on until it cools back down. Its one of the two. What you CAN do is have someone with you who removes the fuel cap and listens into the filler neck as you attempt to start. If they hear noise from the fuel pump that would indicate that the coolant sensor is bad and likely needs replacing. That would be the EASIEST way to go about it. What you could do as well is when you are having the hard start issue is reach for access and disconnect the coolant sensor (it should be located in the back of the engine by the fuel rail.) You may have to remove the engine cover and air cleaner assembly which is really easy to do. If it starts that indicates to you that the sensor is likely malfunctioning at heat soak and you should replace it. Make sure right before you disconnect it that the vehicle does not start, better yet, make sure you disconnect it while it's having the hard start issue.

By disconnecting the sensor what you are doing is giving the ECM the ability to substitutefor a known good value that is in within the operating range of the coolant temp parameters. If that fails, attempt everything within your powerto listen for the fuel pump making noise, by doing the method I told you above.

 

That sure is an intricate theory. What makes you believe that a sensor wire is shorting and causing the ECM to shut off as a protection?

OP have you taken this thing wheeling or been through some deep mud at some point? If you have, it could very well be that you have a clog in your system.

 

I read stuff. Also I have disabled my evap system, because it broke (physically smashed). I just unplugged it and rerouted the vent lines. It has a code and the MIL is on, but otherwise runs fantastic.

http://www.customtacos.com/tech.old...06toyrm/06toypdf/06rmsrc/rm2006ta/0050060.pdf

http://www.customtacos.com/tech.old...06toyrm/06toypdf/06rmsrc/rm2006ta/0050058.pdf

There are several valves in the system that can fail. If one of them does, the evap system doesn't work. It doesn't have to be clogged with an outside source like mud.

 

I rarely ever go wheeling or get the truck overly dirty.

I'm taking the charcoal canister apart right now and going to blow out all the lines and see if that helps.

 

Interesting. I gueess even the EVAP is relevant in this system. Let us know how it works out OP. I hope that solves your issue.

 

ok so im back. i took apart the charcoal canister and blew out all the lines, but i was unable to get the actual canister out from under the bed of the truck. i did however give it a blow out too. i let everything sit before i put it back together. i hadnt had the problem since. i thought i possibly fixed it, until today. yesterday i went to the usa and filled my tuck up with fuel. i definatly didnt over fill, i stopped at the first click. today i drove to work in the morning and before i was ready to come home i checked it as it was sitting in the sun all day and it wouldnt start. i removed the gas cap and the line under the hood from the canister and let it sit for a few hours and it was good to go again. could it be the actual canister thats clogged? is this something i can buy new or would a wrecker one work? is it worth it to try changing it out?

 

There are several valves in the system that can fail.

If I were you, I would just take it to a mechanic. I'm not you, I'm me, and I would have fixed it myself two months ago by following the clearly outlined instructions set forth in the FSM to troubleshoot the various kanooter valves that control the flow of fuel vapor. Just sayin'.

I might be wrong, and if that is the case I owe you a bottle of Pendleton's finest the next time you are in Oregon.

 

im very good with basic automotive stuff its these new cars with all there sensors and valves that trick me. how can i test the valves? lets check your theory, im just in vancouver canada and occasionally pass through oregon. i could take you up on that bottle lol

 

Ha! I'll stick to my word. I don't know which valve it is exactly, so go fish. http://www.customtacos.com/tech.old...06toyrm/06toypdf/06rmsrc/rm2006ta/0050058.pdf

My guess based on this wording in the above link-
"Do not perform the EVAP SYSTEM CHECK when the
fuel tank is more than 90 % full because the cut-off
valve may be closed and making the leak check of the
fuel tank unavailable.
• Do not run the engine in this step.
• When the temperature of the fuel is 35
°
C(95
°
F) or
more, a large amount of vapor forms and any check
results become inaccurate. When performing the
EVAP SYSTEM CHECK, keep the temperature below
35
°
C (95
°
F)."

 

right on, thank you. I will check it out tomorrow and report back!

 

Based upon the fact that you pulled the line under the hood and removed the gas cap and it started a while later would indicate nearly nothing to me. You should had done that and attempted to crank it right after, as long as that line does nothing but control evaporative emissions and is not immediately tied into the fuel system to cause some sort of leak.


When it comes to this stuff its best to play process of elimination and attempt to see if the problem is solved right then and there immediately after you attempt the different method or the supposed fix. Now if this is your problem fantastic. If not, I would urge you to make sure your fuel pump is not being affected by changes of ambient temperature. Using the methods I have stated to you before. All very easy to do.

 

heres my latest update: replaced the charcoal canister and valves and encountered the issue again a few days later when it was hot out. thinking about changing the crank position sensor next. any thoughts?

 

Sub'd

Replace the following sensors:

1.) Coolant Temperature Sensor
2.) Air Filter Temperature Sensor
3.) Mass Airflow Sensor.

 

which of these sensors could prevent the ecu light from coming on when i try to start the truck??

 

From what has been posted here on previous post, descriptions, etc., that sounds like it would be a 'software' problem in the trucks ECU, that can't be fixed, only Toyota engineers would be able to figure that one out as to "why" and resolve the issue?
Try to remove each sensor one at a time, each time following, trying to start the truck and see which one would allow a 'code' or CEL to appear? But this really may or
may not give you false code, etc. or the results that you are looking for because as mentioned before it appears as though it has something to do with the software, installed in the trucks ECU.

Replace all three sensors and that should take care of the problem.

If not then your only two options would be to continue trying to figure out the problem or it's time to take it to the dealership (and they probably won't be able to figure it out either that is unless they are already aware of this specific problem and know exactly what to do, doubt it though).

Good Luck!

 

I'm just going to give it to you straight, keep in mind I can not be 100% without having the vehicle to test certain things to see if you're receiving signal from the ECU, generally if you have a check engine light that does not come on and the vehicle that does not start it is usually a bad computer. When it does not start you can back probe wires using a voltmeter at the ECU to see if the computer is sending out fuel injection pulse, crank signal, and ignition coil signal, if the computer does not send signal to any of those it means your ECU is bad. All 12V signals that supplies fuel injection pulse, Ignition Coil, Crank Signal usually comes directly from the ECU. (would need to look at wiring diagram to confirm) I am in the automotive repair business, I use to wrench but now just work as a service advisor. I would highly recommend taking it to the dealership or a Toyota specialist that has the capability of replacing a ECU and reprogramming. The pass 2 cars which were a 4runner and a Nissan Frontier we had that we diagnosis it as a bad ECU, both of them would not show a check engine light in the on position and no reading through the obd2 port. I am currently working on a Jeep Grand Cherokee with intermediate no start, with similar problems like yours, vehicle does not start unless the check engine light is on.(with key in the on position) No injector pulse, no signal to coils, no crank signal when check engine light is not on. We have a computer coming in soon for that also to verify if that is the problem. Also keep in mind if you take it to the dealership, make sure they try to replicate the problem by parking it outside in a hot day or run the vehicle hot, they will no be able to diagnosis the problem unless the problem is occurring when the check it. If it doesn't occur they're going to tell you there is nothing wrong with the car or they will be unable to diagnosis because they can't replicate the problem.

 

Check for intermittent EFI fuse link...could be temperature dependent on make or open circuit...This fuse qualifies with VC for ECU output. (Cheap and easy enough to just replace!)

 

Out of curiosity have you had one of your local auto part stores put a battery tester on yours. I've had batteries with a bad cell that is intermittently shorting out. Sometimes it starts fine and then 30min later not at all. Makes it seem like you have major problems when you don't. Anyway it's generally free to test and a good thing to check before you go through hell and back chasing ECU problems. Remember a volt meter showing 12 volts and you saying it starts sometimes is not conclusive that your battery is fine.

 

Ummm guys the OP was over 2 years ago...I'm sure he's gotten it to start by now, or gotten rid of the thing