Fuel Pump Nightmare ongoing

Hey Tacoma World. I’m hoping someone out there has some info that can help me resolve an ongoing fuel pump issue.
- I have familiarized myself with the available fuel pump related discussions here, at least I think I’ve seen all pertinent posts.
- my issues started with a dying fuel pump, failing intermittently for a few weeks, after which it stopped working altogether. - I replaced it with a new OEM unit, the entire sender assembly. Still a crank no start. Replaced FP relay, replace c/open relay, FP resistor, and still no fuel pressure. Verified with brake Cleaner in the intake that it had spark. - Towed to a shop, told me my fog light relay, which shares the ground circuit with the FP relay, wasn’t grounding, thus preventing power to the fuel pump. - drove truck home and used a few weeks. Dies again, same symptoms, and crank-no start condition. Towed it to a shop this time. They said my new fuel pump was kaput, having burnt the electrical Contacts, and the pigtail connector to the pump also had burnt contacts. - the shop replaced the fuel pump with another new OEM unit, and they replaced the pigtail connector to the pump. Additionally I replaced all the relays in the block, from denso.
- 4 months later it’s presenting with almost identical problems. Except this time it’s starting up every time, but dies within 5-20 seconds. Left me stranded the other day, had it towed to the same shop. Shop hasn’t gotten to it yet, but did say they drove it a bit and presented no issues at the time.
- - my main question here is: - what kinds of issues could create the FP connector to burn, and also cause the pump to die and malfunction this way?
- thanks in advance for any input.

 

Corrosion is usually the culprit, green death on the wiring.

It's actually not that common on Tacoma, but Tundras get it. And its very common on Chevy trucks. So much so that when you order some chevy fuel pumps, they come with pigtails.

Obviously fuel pressure has to be tested next.

I think what needs to be done next after is checking the wiring under load, which is a bastard because of where the tank is. I usually drop the tank and let the pump hang while I test it. Huge PITA.

 

So it starts up every time now, but dies shortly there after?
I’d bypass the fuel pump resistor temporarily and see if it continues to run.

 

Yes was starting up every time, and running 5-20 seconds-ish then dying. - I’ll follow up with shop tomorrow and see if they’ve tried bypassing resistor. - my biggest concern is that something is killing my fuel pumps. Or at least that how it seems right now.

 

If it starts every time and dies after a few seconds it definitely sounds like it could be a problem with the fuel pump resistor circuit or fuel pump relay as it always starts on high speed and then switches to low speed after a few seconds.

The fuel pump relay only controls the high and low speed, the fuel pump on/off is controlled by the C/OPN Relay.

 

The fuel pump relay and the fog light relay do not share the same ground.
The fog lights themself do. But not the relay.
The fuel pump relay actually gets a ground the the ECU.

The EFI relay is what powers the fuel pump relay.
And it does share the same ground as the fog lights.

 

Guys Thankyou for the input.

 

Apparently there’s an issue where a terminal is getting burned on a connector in the drivers side kick panel(curved panel by door). It’s a white connector with a black and red wire and they are melting for whatever reason. You may need to replace the terminal or connector for it.





If that’s not the issue, you may want to check the pin fit on the connectors on top of the fuel tank. I’ve seen loose terminals there before. I’ve also seen loose grounds.

 

Frank the tank Thankyou for taking the time for that!

 

No problem, hopefully this fixes your issue

 

I will follow up with new info and what I find out is the cause

 

So the other day the shop said to “come get your truck.” They drove it 12 miles testing and couldn’t get it to present any issues. - picked it up, let it idle a bit in front of my house, and cautiously set out for a test drive. - Died 300 feet from my house. - made shop tow me back to their place. - It was still starting up every time like normal, but then dying within 5-10 seconds. - I was suspecting something with fuel pump resistor, reading that the resistor isn’t working until a few seconds after startup. - the tech did find the harness connector to the resistor, and the resistor connector to be burnt and fubared.

 

I had replaced the resistor several months ago chasing my fuel issues. So I’m not sure if I missed the burnt connector pins or if it happened after replacement. ‍idk
- I was surprised to find at my local Toyota dealership in Carlsbad, they had in stock the resistor, harness connector, and pigtail replacement/repair.
- Part numbers for anyone interested.
- resistor assy:

$73 23080-31010 Fuel Pump Resistor

23080-31010
- housing, connector:
90980-11156
- terminal, repair
82998-24410

 

Still won’t have it back until Monday, as shop is closed for the holiday weekend.

 

Nice find

you are really close to me actually. I’m currently in San Marcos

 

Can you just cut that connector out and solder it..may have had a loose pin fit there

 

Thanks for the update.
It sounded like a resistor/wiring issue.

 

Oh nice. I’ve got family off twin oaks and my parents are in vista. - frank your detailed feedback on the location of that connector behind the driver side kick panel leads me to believe you work in automotive?

 

Yep loose pin fit/burnt pins. Opting for as thorough a repair as possible with the new leads and connector, on account of how big a MFing headache this fuel issue has been since it’s onset like freaking 8 months ago almost.
-if I had caught this burnt resistor connector at home or even where it most recently died near home, I’d be more inclined to do the connector repair myself with some heat shrink solder connectors. But it’s at the shop around the corner. “Brads foreign and domestic.” - I suggested to the tech they look at the resistor based on how it was presenting he found that to be the case, so I’m resigning myself to them doing the connector repair and that it’ll be kinda gouge-ey $$.

 

I worked as a Master diagnostic technician at a Toyota dealer in San Diego for 7 years. I now work for the county as a master fleet technician on heavy duty trucks and sherriffs for north county