2013 4.0 - Cranks, doesnt start. Sudden fuel pump failure?

Update: I just re-tested the voltage WHILE CRANKING and I got 9.xx V while cranking at pin 2 and 3

 

Read this if you haven’t, I’d almost bet if you pull that plug you’ll find the burnt pin
https://www.tacomaworld.com/threads/fuel-delivery-issues-2013-v6.661519/

 

Thats the same thread I linked to earlier. I did pull the pin but was texting with my brother in law who is a mechanic and was guiding me through some other electrical diagnosis.
I did see a little burning on the plastic around that pin but I havent checked that pin closely itself yet. I kinda FUBAR'd it getting it out so Ill have to repin it anyway I think. oops.

I did a resistance test on the wire I pulled and got about 2.5-3 Ohms, which, according to my BIL means the pump might be fine. Though if that pin was bad, would you not expect to get bad readings? (excuse the ignorance with that question, I really am ignorant electrically.)

 

Lol me too but from what I have read too the pump just might be fine.

 

THE FUEL PUMP IS FUNCTIONAL.

I pulled the red/black wire from the IB2 connector at the drivers side footwell and connected a fused 12V connection directly to it and the pump turned on. Only left it connected for a second (twice to confirm) but it without a doubt turned on.
https://imgur.com/Te6PJVG


And now that I tested the Fuel Pump Replay while cranking and getting power where expected AND power from this wire to the fuel pump turns it in, there is a disconnect somewhere in-between.

 

Likely was a bad connection there and you messing with it fixed it at least temporarily.
Will the truck start now?

 

I havent put that pin back in the connector yet. I just wanted to 1) see if the pin was burned out like I read in another thread with the same/similar problem and then 2) while it was out just provide direct power to see if the pump turns on, which it did.

Ill put it all back together, if i didnt mess up that pin too much, and see if it starts.

 

OK - so the truck fires up now. I left it running for 5 minutes, turned it off twice and back on again. Ill let it sit for a while longer and go again and see if it continues to work.

I literally did nothing other than provide direct 12V power to the red/black wire under the dash. Nothing is currently bypassed. I might have a relay or 2 in a different spot than when I started but those swaps did not have any affect previously.

While its great that this is working... why did it work? Nothing changed. I worry whatever the root cause is will show itself up again soon.


THANKS TO ALL WHO HELPED THROUGH THIS. All of the guidance got me to this point to even have a chance at making it work.

 

Sometimes when there's a bad connection in a connector simply unlplugging and plugging it back in will fix it, sometimes temporarily sometimes permanently.

 

Well since I have everything apart and that pin is rather easily accessible right now, might make sense to just replace it just in case.

Is that a part that is readily available/universal or Toyota specific? Needs a special crimper?

 

You would have to find the correct pins for that connector, most of the time they are sold with wires and you just splice them on.
If you have a pick n pull nearby you could maybe grab a whole connector and have all the pins you need.

 

I know they do (mine does too) but mine only cycles at key off if the engine was running.
The humming I'm pretty sure is the throttle body, it's normal for them to do that KOEO.

 

Did you try the P/N in the pic above? Seems it was the exact same issue. If I had to guess, the process of you un-plugging / plugging IB2 back in was enough to break up some of the oxidation and get better contact. Id bet the problem will be back at some point in the future though. If you can easily source parts probably just as well to fix it once and for all while youre there