05 Crank no start

Hey y'all, be grateful for any assistance with my situation.

2005 DC with about 235k miles. Above average maintenance to include MAF/TB cleaning, plugs, filters...etc Full tbelt and all that about 40k/5 years ago. Never a single issue with the rig until this and since I don't have factory diagnostics available I thought I'd ask for a hand as I' sure this has come up in the past.

*Truck has been running fantastic up until yesterday morning when it wouldn't start for the first time. Never a hiccup, never a poor idle, never a hard start and not a single issue even the night before I parked it. Battery is GOOD/charged, starter is healthy sounding. Cranking sounds absolutely normal except that the truck doesn't "catch" and fire up. No stumbles or almost catching, just a cranking as if the spark and/or fuel wasn't there...

I've read through a few posts already and here is what I know/have checked:

• Tested fuel pump relay good - haven't checked the circ open relay yet
• Checked ALL wiring associated with poorly routed crank pos sensor (t belt job), cam sensors or any rodent chompage (which happens round here a LOT) and everything looks great - no known issues
• Pulled elec throttle body and cleaned it all up, reinstalled, still no start
• No CEL, stored codes or any issues
• Using my scangauge I can see TPS % function/change as normal
• With key in "on" position, the elec throttle body makes a humming noise constantly. I just noticed this for the first time today which is why I elected to pull/clean and try again. Light tap while humming made no difference.

I am leaning toward fuel pump at the moment and was hoping you all may have a way to test ON truck that doesn't involve cutting any wires (though I'm not opposed if I have to). I don't have garage access now and the weather is snowy/slushing/raining so I'd rather not totally disable truck where it sits unless I have to yet.

I've had pump go bad in past and this isn't dissimilar - I've never had a pump "act up" as I've heard others have, only die once and for all.

Any assistance for next logical step OR how to test the fuel pump without the dealer special diagnostic tool? I suppose I could just pull relay and make my own jumper and have my son connect terminals while I stick my ear to tank to verify.

If I can't do this quickly and easily I will move to checking I have proper spark first and then plan to drop/pull fuel tank.

Thank you all in advance!

 

You said you checked for rodent damage - that included checking the wiring on top of the tank, and behind the glovebox to make sure rodents didn't mangle any wiring to the ECU right?

You understand the purpose of the fuel relay is to route power from one pin position to another, right? Try manually jumpering power to the pump at the relay itself. I'd need to dig up which pin is what. You should be able to hear the pump kick on.

Here's the fuel pump circuitry if you want to understand how the fuel system works.

You can jumper the resistor to bypass, as another test before diving into the relay.

This video may help with which pins to jump on the relay, but disclaimer: Some info in here is false (i.e. pump isn't ON when key is at ON, as you saw in the fuel pump circuitry doc). Also, notice it's for a 2002, so take with a grain of salt about the pins, test first.

https://www.youtube.com/watch?v=VoerlgT8pck

 

Thanks Shifty. I didn't check inside OR at the tank yet, I can and will do that just to rule it out - never a bad idea to go far with the rodent checks where I'm at. They've been known to total vehicles!

This is what I was looking for, thanks for the diagram and video. I didn't have access to computer so these are extremely helpful and should help me further diagnose. That relay slot at the dist block can help me rule out the resistor and pump itself. My relay in my 05' is a 5 PIN though.

 

Yup, my '06 is also 5-pin IIRC.

And re: Rodents above the tank. Let me tell you ... here's how obscured it can be, and an example of mice chewing through fuel pump wires, way up on top of the tank, hidden from view like this. They like to chew thru gas tank plastic tubes and stuff like this. They'll chew through the gas filler neck also, which will throw codes, like this.

Those little SOBs are ruthless man.

 

Found the FSM from a kind soul who posted it up for the 05/06. Used this and checked all relays and they're working just fine.




Took additional pics and everything looks good up there, albeit dirty. Same for ECM/glovebox zone.

I'm solo and I tried applying B+ to terminal 4 and then to terminal 5 of FP Relay when pulled and couldn't hear anything. That is not as definitive as I'd like so I will require a partner for that to double check while I am under truck with screwdriver to my ear. I am not 100% which terminal, 4 or 5, sends power to resistor but it is one of them. It doesn't look like there is anything else in the path from the relay to the pump aside from the resistor - so there should be no reason for the truck to be in the on position to get the pump to react.

Will report back.

 

As shown in pic below, applying batt + to pin 5, sends current thru resistor. That path is what gives us fuel pump low speed during idle or light loads. Fuel Pump relay is energized at this point
Applying batt + to pin 4, sends current straight to pump. That path is what gives us fuel pump low speed during start or heavy loads. Fuel Pump relay is de-generized at this point.

If after re-testing with a companion that the Fuel Pump appears to be working, I would re-visit checking the other items needed for pump operation.....20 Amp EFI No. 1 fuse, bench testing EFI relay, C/OPN relay or other procedure of your choice.

 

Pulled fuel pump relay. Gave wife jumper setup and we tried B+ in both slots, 4 and 5, of dist. block. Had my screwdriver (touching tank under filler) to ear and heard nothing but a few clicks.

Dead pump yes?

Follow ups - I prefer OEM parts but the assembly from Toyota is several hundred dollars. I can buy just the Denso pump and sock from, say Rock Auto, for about $120 it looks like. That is palatable but also requires me to reuse much of the "old". Anyone seeing this do either of the following:

1) Purchase Denso pump and reuse everything else in the pump assembly successfully without breaking anything upon removal, reassembly and reinstall?
2) Purchase some other brand as a complete assembly and have any meaningful chunk of time running it on your rig?

Thank you!

 

Denso is OEM. And yeah, sounds like a dead pump. Only other thing you could verify would be fuel pressure, confirming there is no pressure. If you heard a click and there was already significant pressure on the fuel line, that would be a sign the pump is doing (at least) something.

1) If the assembly, float/sender and wiring is good, go for it. Inspect and clean up the sender contacts if required so you don't get 'sticky fuel gauge' issues.
2) Never. Never ever. Do not use non-OEM parts in hard-to-reach places, or in Electrical. Refer to bullets in "MAINTENANCE AND PARTS" section HERE.

Someone, I think @w666, may be selling a compatible pump in the Marketplace forum, but you should verify part number first.

 

That is my hesitation at this point, especially since it was running 100% a few nights ago. I think I'll just drop tank anyway, pull lines and then I can quick test pump visually and take a look at everything else. Fortunately this isn't my daily.

 

The fuel pump you (may) need is Denso 950-0210.

https://www.rockauto.com/en/moreinfo.php?pk=2143066&cc=1431003&pt=6256&jsn=400

 

There have been cases of no-spark condition when one of the two temp sensors on the block next to the TB go bad, so be sure to test for spark. Suffice to pull one coil and let it arc to something grounded. I'd do that before dropping the tank for sure.

 

Correct….
The pump you’re selling is for 03-04 not 05.
BTW….ever since I first saw your thread months ago, I’ve been debating getting it

 

Successful fuel pump install. I’ll drop a few quick pics to help anyone out that may encounter the same later on.

I opted for Denso replacement, ordered from Rock Auto as well as new tank gasket (big o ring).

I’m in PNW and my truck is pretty much rust free. I spent way more time cleaning up frame and everything I gained access to while tank was out than I did doing the pump R/R. I’m glad I didn’t buy aftermarket other brand…. One can, if careful, successfully pull everything apart and install new OEM without much worry. I can’t think of anything else I’d rather have replaced while in there either.

I did snap one of the tank bolts while backing it out with 3/8 impact. That’s about the only hiccup I had.

Opted to leave the filler/vent and tubes and the charcoal canister all connected and remove as one as shown. Good cleaning prior to any disassembly is a must.

 

Oh and I forgot to mention that when disassembling the bottom of assy the “sub pump” cartridge I did opt to cut the tabs off old setup rather then try to pry them past the tabs on the upper portion I needed to reuse. I felt it safer than potentially snapping one.

cheers!

 

I had to do this last winter. Had the same problem with the tank bolts too. Other than breaking the bolt, it wasn't that bad of a job. That one bolt made it take a least three times as long as it should have been.

 

You go with a Denso or other?

 

I went with Denso 950-0132, which should be appropriate for my truck.

Worked in anycase.

 

You also forgot to mention whether it fired up and purred like a kitten after you got it all bolted back together, or are you waiting for tank bolts?

Could also be interesting to throw a 9v battery on the pump contacts to see if it fires up, but I've seen plenty of cases where in-tank pumps will magically start working when pulled, or even when you smack the tank violently to rattle its innards, so wouldn't take it firing up as a sign it was working right.

 

Purring like a kitten yes.

Old pump bench test = dead.

 

So it's almost never the fuel pump...unless it's the fuel pump.

 

Never the fuel filter. Sometimes the fuel pump.

 

Yep. Mine started working after I smacked the bottom of the gas tank, which was great as it died in a difficult place to work. That was also my diagnostic.

 

I went back out for shits upon cleaning up and bench tested the old pump again - it fired up

Let that be a lesson to those that see the writing on the wall - if you get it "working" again temporarily - move it to a good spot for dropping the tank!