Good afternoon, I am 1984 Toyota Master Tech! I have my youngest Son’s 2001 V6 2wd Toyota Tundra

Good afternoon,
I am working on my youngest Son’s
2001 V6 2wd Toyota Tundra with regular cab long bed!
He is getting a intermittent, No start!
The guy that I bought the Truck from, said that he had to replace the Fuel pump at least 3 or 4 times over the years!
So I replaced the fuel pump with a
Denso pump! But I did a ohm test on the old pump and found everything within specs.
So the Truck runs and sounds great for having 426,428 miles on it!!
But 2 weeks later my son called me and said that the truck would crank over, but not start! so I go check out the truck and the Fuel pump was not running? So I crawled underneath the truck and disconnected the wiring to the fuel pump and checked the connectors, found no problem with the pins and the connector itself and then plugged it back onto the fuel pump and my son cranked the truck over and it started right up!!! So it ran great for about two months! Then I get the call again saying that the truck was not starting again! So I told him over the phone how to unplug the fuel pump connector and reinstall it! Well it started right up again! But now the Truck won’t start again and unplugging the fuel pump connector and it didn’t make any difference!

So I am reaching out to you all and checking to see if anyone has had this problem before and maybe point me in a direction??
Thanks,

 

I have no experience with our fuel pumps, but I would replace the existing wiring plug, and internal terminals on the one you keep unplugging.

Sounds like it's losing connection at the plug? Possible heat expansion, or previous owner damaged internals on plug once or thrice?

 

Thanks Noah I have already replaced the connector and Soldered in the new connector’s

 

Replaced the fuel pump, probably because of this exact issue. And hopefully, you know the fuel pump doesn't power-on until you tilt the key forward/

Did you check all the dash fuses, and the EFI fuse(s) under the hood?

Have you tried bypassing the fuel resistor?

Did you test the coolant sensor(s)? I know my V8 has two, one for the dash gauge, one for the ECU, and some members found if the ECU sensor was bad, it'd cause no-start issues.

Are there any codes at all, related to crank position sensor or cam position sensor?

Here is the fuel pump circuitry, so you can understand what triggers the fuel pump to engage, but again, this is for the 2UZ unfortunately: https://www.tundras.com/attachments/fp-pdf.794298/

The following content is related to the V8/2UZ-FE not the V6/5VZ-FE, but maybe it'll help you to track down the issue, or at least find more symptoms. Specifically this post has some jumpering info for start problems: https://www.tundras.com/threads/solved-crank-but-no-start-07-sequoia.114911/#post-2957271

And this one has some things you can do to jumper and force the fuel pump to come on, but note, has some misinformation, i.e. the fuel pump is NOT on when the key is in the ON position: https://www.tundras.com/threads/solved-crank-but-no-start-07-sequoia.114911/#post-2957102


I'll also say, some found corrosion at one of the wire bulkheads between the dash and fuel pump that caused problems. And rodents LOVE LOVE LOVE to chew up the wiring on top of the fuel pump, and also love to get under the intake on the V8s specifically to chew the knock sensor/starter wiring.

EDIT: There are links to the FSM in the 4th or 5th paragraph of THIS POST. It may help w/diagnostics.