(very intermittent) Hard starting issue - 2014 v6

so long as its a 4x4 on 09+ then it has the electric boosted master cylinder. It literally has a little electric hydraulic pump that stores pressure in the aluminum cylinder on the master cylinder (looks like an oil filter with a nut on top of it). Nope its not like the hydro boost setups on bigger chevy trucks, where you lost ALL brake boosting when you shut the motor off because the power steering pump wasnt running.... least with a vacuum boosted setup you get one good pedal stab. The electric boosted of the trd or 4x4 09+ will always be on as long as the key is in the run position.

 

I will also add that my factory battery crapped out at about the 30 some k mark and was replaced under warranty. I did not have any long start issues after this point. Didn't think of it before but certainly could be related. It was a bad cell. Tested fine with voltmeter but not under load. Started fine to run an errand and wouldn't so much as click over when I tried to leave my destination.

 

2008 prerunner TRD, 6 cyl starting issue, turns over, starts, 2 seconds later it dies. happens again and again. Started 2 years ago.

Never heard fuel pump run when key turned (never have before either)
Hit bottom of gas tank with rubber mallet, sometimes starts and runs fine.
Had fuel pump replaced 2 yrs ago. was ok for a year, then started happening again intermittently. Happens more often the last few months.

Happened again yesterday, heard something different than I never heard before: buzzing sound around top of engine when key turned. Still couldn't hear fuel pump running. ldn't determinme where sound was coming from.

Tried several times to start, failed

Finally hit tank again with mallet, started and ran fine. Has started several time ok since.

Temp outside yesterday was 50 degrees, a substantial drop from previous days.

Hate to put in another $1000 pump.

Also, is there a fuel pump relay under the hood? If so, where?

Ideas please??
Thanks and stay safe
Don

Factory pump 2 yrs ago, out of warranty

 

https://www.tacomaworld.com/threads/08-prerunner-6-cyl-hard-to-start.690644/

 

2008 prerunner TRD, 6 cyl starting issue, turns over, starts, 2 seconds later it dies. happens again and again. Started 2 years ago.

Never heard fuel pump run when key turned (never have before either)
Hit bottom of gas tank with rubber mallet, sometimes starts and runs fine.
Had fuel pump replaced 2 yrs ago. was ok for a year, then started happening again intermittently. Happens more often the last few months.

Happened again yesterday, heard something different than I never heard before: buzzing sound around top of engine when key turned. Still couldn't hear fuel pump running. ldn't determinme where sound was coming from.

Tried several times to start, failed

Finally hit tank again with mallet, started and ran fine. Has started several time ok since.

Temp outside yesterday was 50 degrees, a substantial drop from previous days.

Hate to put in another $1000 pump.

Also, is there a fuel pump relay under the hood? If so, where?

Ideas please??
Thanks and stay safe
Don

Factory fuel pump 2 yrs ago, out of warranty, gonna replace the fuel pump replay,
then efi, then copn

Any idea where the pump resistor is located?

And THANKS for all the help!

replaced fuel pump relay, lasted a month, failed again,

still need location of fuel pump resistor please

still looking for the fuel pump resistor is located

Last edited: 5 minutes ago

Update.. finally replaced all relays above and checked two efi fuses, all good, still failed. Took it to dealer, had no codes, he also said efi relay was in wrong place, yep, I probably did that, and 20 amp efi fuse was missing completely, I didn't do that,
Said he put efi relay in proper position, replaced fuse and it started. He advised the cpu sometimes did not use that efi circuit and that's why the truck had an intermittent starting problem.
It's been two weeks with no problem. we shall see
Fuel pump resistor is in front of battery and it's ok
Thanks to all who responded, this is a great site with great people

 

2008 prerunner TRD, 6 cyl starting issue, turns over, starts, 2 seconds later it dies. happens again and again. Started 2 years ago.

Never heard fuel pump run when key turned (never have before either)
Hit bottom of gas tank with rubber mallet, sometimes starts and runs fine.
Had fuel pump replaced 2 yrs ago. was ok for a year, then started happening again intermittently. Happens more often the last few months.

Happened again yesterday, heard something different than I never heard before: buzzing sound around top of engine when key turned. Still couldn't hear fuel pump running. ldn't determinme where sound was coming from.

Tried several times to start, failed

Finally hit tank again with mallet, started and ran fine. Has started several time ok since.

Temp outside yesterday was 50 degrees, a substantial drop from previous days.

Hate to put in another $1000 pump.

Also, is there a fuel pump relay under the hood? If so, where?

Ideas please??
Thanks and stay safe
Don

Factory fuel pump 2 yrs ago, out of warranty, gonna replace the fuel pump replay,
then efi, then copn

Any idea where the pump resistor is located?

And THANKS for all the help!

replaced fuel pump relay, lasted a month, failed again,

still need location of fuel pump resistor please

still looking for the fuel pump resistor is located

Last edited: 5 minutes ago

Update.. finally replaced all relays above and checked two efi fuses, all good, still failed. Took it to dealer, had no codes, he also said efi relay was in wrong place, yep, I probably did that, and 20 amp efi fuse was missing completely, I didn't do that,
Said he put efi relay in proper position, replaced fuse and it started. He advised the cpu sometimes did not use that efi circuit and that's why the truck had an intermittent starting problem.
It's been two weeks with no problem. we shall see
Fuel pump resistor is in front of battery and it's ok
Thanks to all who responded, this is a great site with great people

 

@dbrown1852

The fuel pump resistor is in front of the Battery.

 

Thanks JimmyH for your help. Finally took it the the dealer, sadly. It seems to have completly failed, turns over, doesn't fire.
Big bucks I'm sure. Will let all know what if anything they find

 

I am extremely interested in your rather uncommon heat exchanger there.

 

Please update when you find out.

 

Not mine I just stole that image from some innocent bystander. LOL

Looks to be a standard water to water industrial plate heat exchanger.

https://www.google.com/search?q=pla...UNa80KHSljDJQQ_AUoAnoECAIQBA&biw=1728&bih=804

 

I had a Ranger that was a little hard starting at times, and it seemed to have something to do with temp changes. Figured out it was the IAC that was going (after checking the MAF and throttle body). It was never cleaned, and at the time it started happening, it was 200K+ miles. Cleaned it out, and the starting problem went away until it (the IAC) totally went a few thousand miles later. Got a new IAC, and no problems since.

The IAC (before cleaning) was carboned/gummed up so the computer had a hard time controlling it. This was especially prevalent when there was a quick change in temp. I assume it was because the computer bases some of it's setting at startup based on last known parameters, and when there is a big/quick change, could not readjust the IAC properly quickly enough cuz of the "stickiness" of the valve. Of course, an argument can be made that at startup it's going on open loop parameters, but even then it may have been that the computer had a difficult time kicking/resetting the IAC to accommodate closed loop setting because the valve was stuck in a bad position.

I assume one could try tapping the IAC when it happens to see if it loosens up?

Note, I am NOT familiar with the Taco V6, and I don't remember if the Ranger IAC was PCM or PWM, but I do remember it worked by duty cycle as I believe most modern IACs do.

 

There is no Idle Air Control Valve on the Tacoma 1GR-FE.