engine cutting power at high speeds ?

[Darklight]

Well software update didn't fix it and they've tested everything they can think of. Everything seems fine with all the sensors and electronics. There best guess is it's the fuel pump and filter. Not sending enough fuel at higher rpm. Even though it passed the fuel pressure tests. They quoted 900 for the fuel pump and filter to be installed. Not even sure that's it.
Anyone ever installed a fuel pump and filter before?

[chayos00]

Originally Posted by chayos00

Just discovered something when I was looking for 4.0L upgrade parts due to watching Engine Masters on YouTube. Food for thought if it turns out to be fuel delivery related.

URD Fuel Pump/Filter Kit, 2003-2009 4Runner V6

Edit - Discovered they are actually URD products and cheaper on the URD website.

Well you ought to check this out if they want the fuel filter/pump. Would make it easy to fix in the future too.

[Darklight]

Yes I am looking into this kit. Thank you for the link and info. Sounds like this replaces the stock in tank pump filter with an external pump filter. That would be easy to change down the line and the cost is way less. Interested to see what URD says about my issue and this products install info. Only thing is the toyota fuel pump assembly comes with a new sender wire harness. That is an import part for my issue possibly. But then again this is not really a definitie fix for my issue. Hope it is though.
Just going to keep on going and hope a light or code will get tripped. Maybe now with the new software it will be more sensitive to it.

Bobby

[BlackWorksInc]

Originally Posted by chayos00

Well you ought to check this out if they want the fuel filter/pump. Would make it easy to fix in the future too.

What I don't get is that the kit they show has a fuel filter sock just like the factory unit, so it makes the in-line external fuel filter moot and a potential fuel line failure point.

Also I can't say I've seen too many units clogging up in "30,000miles" (or even 100k) that'd fall under 3yr/36k bumper to bumper, that'd be A LOT of warranty fuel pump replacements. Normally I like URD and those guys seem to be pretty good and knowledgeable on most things, but this particular statement just doesn't pass the sniff test. Most fuel pumps fail from overheating (they're cooled by the fuel itself, so running the tank excessively low constantly can burn them out) and/or excessive voltage drop.

All that being said, it could be an issue with the fuel pump, but it's hard to say. I honestly would not have expected the "software updates" to fix the issue. The main reason is that the BST update (probably either the first or second software update revision available for the vehicle, I forget which is first) is only detailed to install the brake/accelerator cancel function (i.e. holding the throttle then pushing on the brake causes the vehicle to cut to idle so you can't have an "unintended acceleration event"). Now that doesn't mean there haven't been improvements to the ECM coding that could benefit you, it just means that there's no real definitive "Patch Notes" that tell you exactly what the software does for every aspect of the vehicle, besides putting in the brake override software.

I wouldn't expect an issue in the ECM to be fixed by a software update unless it is specifically detailed in the TSB/Software Update technical instructions (i.e. "This Software Update fixes an issue with DTC P0XXXX being set and/or an occasional mis-shift in 3rd gear in weather under 40*F when the vehicle is cold.) It's possible, but highly unlikely; this just sounds like a "we've tried everything else, lets just give this a shot and cross our fingers" thing.

[Darklight]

Thanks me for all that info. Nothing fixed the issue and the best bet is try replace the fuel pump filter assembly which I plan on doing with toyota fuel pump assembly.

URD recommends replacing their fuel filter every 30k and it does not include the sending unit and other items the fuel assembly includes. Might install it myself as well.

Bobby

[BlackWorksInc]

Originally Posted by Darklight

Thanks me for all that info. Nothing fixed the issue and the best bet is try replace the fuel pump filter assembly which I plan on doing with toyota fuel pump assembly.

URD recommends replacing their fuel filter every 30k and it does not include the sending unit and other items the fuel assembly includes. Might install it myself as well.

Bobby

That doesn't surprise me with an in-line unit, I'm just curious why they would bother with an in-line filter if they show a sock filter for their kit. The main reason in-tank units have a sock filter on the end is because that's what prevents debris from going into the pump (the first thing it goes through in these systems is the pump). So if they don't put a sock on the pump inlet it's going to have stuff eating away at the pump and then getting filtered into the in-line filter, which seems like a good way to sell pumps. But putting a sock filter on the pump makes the in-line filter mostly redundant as the fuel should be fairly clean by that point.

I'd be curious what URD's statement is in regards to that.

As for replacing the fuel pump, it's worth a shot. I'd need to see more data and how the dealership tested the vehicle's fuel system to be sure that's a possibility. But fuel starvation at higher load could be the issue. I also wonder if the fuel pressure regulator might be acting up somehow?

[gshadow325]

My Volvo's would do this when the maf sensor was bad and or one of the hoses was loose or had a hole in it. It would really hate it when one of the pipes going into the throttle body was disconnected. It would fall flat on it's face when I was accelerating. Like someone turned on the tractor control.

[Darklight]

Things the dealership tried included: fuel pressure (seemed normal but not sure at 4K rpm) , swapped mass airflow sensor, swapped accelerator pedal position sensor, hooked up scope to crank shaft speed sensor. Checked gas. Inspected all vacumme tubing and lines in engine bay. No problem found and said it is very hard to diagnose since it only happens at high speeds.

[chayos00]

Man this is just one weird issue!! I've never really looked into the fuel assembly before suggesting the pump from URD, just thought it was an interesting idea. If it was what I was needing, I would have researched to the ends of the world before making a decision. LOL

Blackworksinc - Do you think with the fact that Darklight is at 100k+ on the factory tranny fluid that could play into this at all? I'm not sure, but I know when I flushed mine around 80k it made the shifting feel better.


Either way it sure does sound like it's starving for something feeding the engine. Just to confirm in the low gears WOT does work up to redline right? Or just in the 3rd+?

[Darklight]

Starting to wonder if it's just bad gas. Seemed fine this morning. Didn't get it to redline but it went when I needed it too. Went up to 5.5k at high speeds.
Shifting is smooth and always has been.
The issue happens at high speeds when accelerating hard. From a start it did happen once getting up to speed at a lower gear maybe 2 or 3rd. Still can not get it to redline as I usually never throttle up that hard to begin with. After all this I have tried several times but was unsuccessful.

[Darklight]

Just an update here. I haven't been experiamenting with flooring it lately. I did have a weird issue today. While attracting it acted like it didn't want to turn over but then it did. Really starting to think it is the fuel filter pump sending unit going bad. Guess I'll be doing it soon.

[Robinhood4x4]

If you're going to drop the tank, you might as well replace the gauge level sensor too.

[Darklight]

It's all a part of the fuel pump assembly from what Toyota is telling me.

[BlackWorksInc]

Originally Posted by Darklight

It's all a part of the fuel pump assembly from what Toyota is telling me.

Yeah I don't think they sell that stuff separate anymore, they used to.

[tomcat144d]

A wee tid bit the 03 06 by owners manual states 91 Oct recommended. I've 05 got 240k on mine never changed fuel filter socks or anything else but plugs every 50k ngk ir type tranny drain and refill 30k with toyota fluid. Use only Shell or Chevron all is good. From what I've read here I wouldn't switch out the fuel pump if fuel rail pressure read good and spec. May be attach a gauge and go on a test drive and watch pressure ir there's a drop under hard acceleration then start with pressure regulator cheaper then move to pump and repeat pressure testing. Could also be a fuel pump relay check voltage. With out a DTC code it's hard to pin point without trouble shooting diagnosis.the 750 e/f transmissions are pretty strong. How ever if ya over heat it there could be a point of failure. Tork Convertor sends the power to transfer case then to front and rear differentials. If rpms stay consistent no acceleration something could be slipping. If your local lodi ca I have a scanner live data eobd obd 2 obd3 abs ect laptop connection that would give you throttle % at ideal relative total % let me know willing to help if I can

[tomcat144d]

Fuel Pump Assembly - Toyota (77020-35112) 510.99
77169-30050 / Fuel Pump Assembly Gasket 3.02
I found em here
Just fuel pump

Fuel Pump - Toyota (23221-31050) 257.81

https://www.discountpartsmonster.com...Y2LWdhcw%3D%3D


https://www.discountpartsmonster.com...Y2LWdhcw%3D%3D

[Darklight]

Thanks brother for that in depth info! I hope it helps someone out.
I never changed the fuel pump or assembly but was pretty darn close.
Seems to be fine and dandy though. Thankfully it was a very easy fix and I feel kind of embarrassed to say what it was.
Ended up being my outerwear pre filter at the end of the stock inlet scoop. It was clogged up pretty bad. Like a birds nest of mud and crap. Removed it all together and problem never came back. Don’t know how I forgot I had it or to check it. After all the headache of checking everything too.

[tomcat144d]

No problem glad to here that ya figured it sounded like it would of been like that keep on trucking

[alia176]

I just read this thread and glad to hear the outcome was favorable. Now I can head off to work!

[Darklight]

yes very thankful it was a super easy fix and just something I overlooked as well as Toyota. 150K miles almost now and just getting broken in,

Keep on truckin!