P0171: System too Lean (Fuel Trim) (1 Viewer)

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A slow degradation like failure mode wouldn't necessarily be subject to a recall, but 140k miles for a Toyota / Denso design, on a Lexus / Land Cruiser doesn't meet expectations.
Agreed. Thanks for further digging in to this.
 
Write-up of repair procedure here
 
Welp, I may be on this path, too. I tested using the procedure found in a tube video, in which the mechanic puts the tester on a Toyota 4.8. Looked similar enough.
  • engine cold, over night
  • (foot off brake pedal) two 'start' button pushes *should* have brought pressure up in system (per video). It did not. (who knows, maybe the LC does not do that)
  • (foot on brake pedal) single 'start' button push to start engine. Engine starts, get out to check fuel pressure gauge: ~32psi
  • rev engine, get out, check fuel pressure gauge: ~25psi
  • rev engine while standing and hanging over door to get video of gauge during revving: ~25psi idle, drop to ~22psi at start of rev, no higher than ~32psi at max rev (note: did not redline, just gently rev up to ~2k RPM.
Notes:
  • My battery was not super great anymore, and being an AGM in this LC I suspected some weakness; replaced with new lead-acid battery last week.
  • Vehicle has 24G LRA installed, but not perfectly done; LRA guys told me I was missing a breather box in the expected/recommended place, but that it *could* be under the tank. Status: unknown (i.e., I have to pull the LRA anyways)
Can we generally agree that I have to perform the @TeCKis300 procedure and replace the pump assembly inside the main tank? If so, it's going to be a huge two-tank wrenching party, during which I will atone for the sins of whoever installed the LRA originally.

Sigh.
 
Welp, I may be on this path, too. I tested using the procedure found in a tube video, in which the mechanic puts the tester on a Toyota 4.8. Looked similar enough.
  • engine cold, over night
  • (foot off brake pedal) two 'start' button pushes *should* have brought pressure up in system (per video). It did not. (who knows, maybe the LC does not do that)
  • (foot on brake pedal) single 'start' button push to start engine. Engine starts, get out to check fuel pressure gauge: ~32psi
  • rev engine, get out, check fuel pressure gauge: ~25psi
  • rev engine while standing and hanging over door to get video of gauge during revving: ~25psi idle, drop to ~22psi at start of rev, no higher than ~32psi at max rev (note: did not redline, just gently rev up to ~2k RPM.
Notes:
  • My battery was not super great anymore, and being an AGM in this LC I suspected some weakness; replaced with new lead-acid battery last week.
  • Vehicle has 24G LRA installed, but not perfectly done; LRA guys told me I was missing a breather box in the expected/recommended place, but that it *could* be under the tank. Status: unknown (i.e., I have to pull the LRA anyways)
Can we generally agree that I have to perform the @TeCKis300 procedure and replace the pump assembly inside the main tank? If so, it's going to be a huge two-tank wrenching party, during which I will atone for the sins of whoever installed the LRA originally.

Sigh.
It is possible to get the module out without dropping the tank but you’ll have to cut the floor of the vehicle to enlarge the hole enough to get it out. @grinchy did this on his aux tank install.
 
It is possible to get the module out without dropping the tank but you’ll have to cut the floor of the vehicle to enlarge the hole enough to get it out. @grinchy did this on his aux tank install.
Yeah, if my aux tank install was solid, i would have considered that. But it all has to come out and be made beautiful.
 
Welp, I may be on this path, too. I tested using the procedure found in a tube video, in which the mechanic puts the tester on a Toyota 4.8. Looked similar enough.
  • engine cold, over night
  • (foot off brake pedal) two 'start' button pushes *should* have brought pressure up in system (per video). It did not. (who knows, maybe the LC does not do that)
  • (foot on brake pedal) single 'start' button push to start engine. Engine starts, get out to check fuel pressure gauge: ~32psi
  • rev engine, get out, check fuel pressure gauge: ~25psi
  • rev engine while standing and hanging over door to get video of gauge during revving: ~25psi idle, drop to ~22psi at start of rev, no higher than ~32psi at max rev (note: did not redline, just gently rev up to ~2k RPM.
Notes:
  • My battery was not super great anymore, and being an AGM in this LC I suspected some weakness; replaced with new lead-acid battery last week.
  • Vehicle has 24G LRA installed, but not perfectly done; LRA guys told me I was missing a breather box in the expected/recommended place, but that it *could* be under the tank. Status: unknown (i.e., I have to pull the LRA anyways)
Can we generally agree that I have to perform the @TeCKis300 procedure and replace the pump assembly inside the main tank? If so, it's going to be a huge two-tank wrenching party, during which I will atone for the sins of whoever installed the LRA originally.

Sigh.

Sorry to confirm, but I think you have enough actionable data to be pretty confident that the pump needs replacement.

I was apprehensive about dropping what was in my mind a big unwieldy tank. Don't be. This was a relatively easy task. Minimal connections and the tank was pretty light so long as you run the gas down. Doesn't help you with the aux tank but it's much much easier than that. I would definitely go from the bottom.
 
Yeah, if my aux tank install was solid, i would have considered that. But it all has to come out and be made beautiful.
Great point. I'd feel the same way.
 
Didn't think I could tear apart the pump effectively, but you encouraged me to give it a short. Was easier than expected.

Cut apart filter sock - looks good.
View attachment 3080283

Working the head off like a tin can. Can already see that the pump impeller fins have wear.
View attachment 3080251

There's clear wear inside on all surfaces with impeller runout. You can see on the circumference of the housing left of the arrow wear from the impeller. On the impeller itself, aluminum transfer marks on ~1/3 of the wheel showing contact with the housing.

View attachment 3080289

Housing and cap showing wear.
View attachment 3080276

View attachment 3080277

The impeller to motor shaft wasn't even clearance fit and slips right off. I attribute the original failure to wear at this interface, allowing play and slop of the impeller.

In the larger Denso fuel pump recalls, they note - Low-density impellers inside Denso branded fuel pumps are cracking and limiting the amount of gas reaching the engine. In that failure mode, it would be catastrophic. Albeit more a brittle failure mode. Fundamentally, it still indicates that the impellers may be low-density and weak.

I believe in my case, that weakness manifested in wear at the shaft to impeller interface driving more premature wear. A slow degradation like failure mode wouldn't necessarily be subject to a recall, but 140k miles for a Toyota / Denso design, on a Lexus / Land Cruiser doesn't meet expectations.
@TeCKis300 : I'm through the fuel pump replacement and have the main back in. Note to obsessive forum wrenchsearchers: you can do this, the information is all here or in TecKis300's repair thread.

Not out of the woods yet, since I'm still atoning for the 24-gallon LRA installation sins of a garbage off-road shop in Atlanta, and reinstalling it correctly without the benefit of the OG installtion kit. Adventure.

In the meantime, here's a visual of my fuel sock and various debris in/around the assembly. Looked pretty gross, and is possibly related to the $*&% install of the LRA. I fully expect 1.2 more horsepower and the mileage of a Prius with the new setup...if it's tight and actually works.

1668401452173.png
 
Looks like the filter was doing its job. The original LRA pump comes with a tiny inline filter too. It might be worth replacing or even upgrading it if you go back in to update the prior LRA install.

I have offten wondered why the petrol 200 doesn't come with a servicable external filter. I know the group chatted about it on here before. It wouldn't help a clogged fuel sock scenario, but might allow is to eliminate the sock and replace it with a high volume inline (and easliy servicable) cartridge. I have to imagine this is an issue seen in places where clean gas is less readily available. Then again, maybe there are more diesel engines in those environments and that engine does come with external filters. It even seems like we have removable factory covers where a fuel filter might live inside the frame rails.
 
Looks like the filter was doing its job. The original LRA pump comes with a tiny inline filter too. It might be worth replacing or even upgrading it if you go back in to update the prior LRA install.

I have offten wondered why the petrol 200 doesn't come with a servicable external filter. I know the group chatted about it on here before. It wouldn't help a clogged fuel sock scenario, but might allow is to eliminate the sock and replace it with a high volume inline (and easliy servicable) cartridge. I have to imagine this is an issue seen in places where clean gas is less readily available. Then again, maybe there are more diesel engines in those environments and that engine does come with external filters. It even seems like we have removable factory covers where a fuel filter might live inside the frame rails.
It’s a relic of the transition to gasoline direct injection, I think. When those started to come out they took a look at fuel quality in the states and realized the vast majority of the time contaminants that make it through the sock can pass right through a port injection system without harming it, unlike in a GDI setup. So those got the filters.

There is definitely a spot on the frame for the filter, and it was equipped at least on Chinese market 200s, from my digging in the parts system. The lines aren’t likely to swap over though, given the other differences in emissions equipment. We could always cut then flare the lines for our own filter.. but it seems people just aren’t demonstrating a need that justifies modifying (and therefore introducing potential failure points into) a quite reliable fuel system.
 
Interesting times. Gone are the bank 1 and 2 lean codes, and fuel consumption closer to normal. Also, LRA plumbing and various body mods are done. So is that awesome anti-squeak CC bracket mod someone here poasted.

Now, however, I'm faced with double the codes related to canister vent and vale stuck on/off codes.

Searched high and low, but cannot find the thread in which someone cut open and diagnosed the charcoal canister, but cannot find. How do you tell if CC is fouled? The valve worked fine on bench test. I also had big hiss on first refuel when opening gas cap. Not normal and it did not do that before 'fix.' Frustrating beyond belief.

Is there an answer on how to plumb the LRA to *not* have venting flow issues?

Gonna call LRA USA tomorrow and appeal for insight, too.

Then, i cut goat and burn incense. Can't hurt. Well, maybe the goat.

Edit/add: mpg must still be horrible at idle. Can see numbers crash in the 'since last fill-up' number at stoplight.
 
Interesting times. Gone are the bank 1 and 2 lean codes, and fuel consumption closer to normal. Also, LRA plumbing and various body mods are done. So is that awesome anti-squeak CC bracket mod someone here poasted.

Now, however, I'm faced with double the codes related to canister vent and vale stuck on/off codes.

Searched high and low, but cannot find the thread in which someone cut open and diagnosed the charcoal canister, but cannot find. How do you tell if CC is fouled? The valve worked fine on bench test. I also had big hiss on first refuel when opening gas cap. Not normal and it did not do that before 'fix.' Frustrating beyond belief.

Is there an answer on how to plumb the LRA to *not* have venting flow issues?

Gonna call LRA USA tomorrow and appeal for insight, too.

Then, i cut goat and burn incense. Can't hurt. Well, maybe the goat.

Edit/add: mpg must still be horrible at idle. Can see numbers crash in the 'since last fill-up' number at stoplight.

Sorry to hear. These emissions things are such PITAs.

What are your codes? From the hiss on the gas cap, I'm suspecting possibly electrical connectors to the evap canister? Possibly not plugged in all the way or something got pinched?

This thread might help?
 
Looks like I continued my saga on one of your other threads.

 
More data points as I changed fuel pumps lately. In short, my 2013 200k mile fuel pump didn't show excess wear like Teckis had going on in his. Also my fuel filter sock and tank was very clean.. I would say it's a function of fuel region but half of mine was in a very different part of the country.

While there was no slop or ability for it to wobble, it would slide snugly in and out, I believe the impeller is designed to float on the shaft, with the pressure forcing it to "ride" on the flat lower retainer of the pump. There was one area on the lower suction side that had a bit of a pit which I believe is due to cavitation.. but it's on the low pressure side, and didn't appear to impact the impeller in any way. All the damage visible on the impeller was from me trying to pull it out of the pump.. before realizing it would come out itself by tapping the pump on the work bench.

On the pressure side there were areas where the anodizing had been stripped off but those areas were still smooth and free of physical defect.

Pictures

Suction side of impeller. The damage on the vanes is from me pulling it out. Note that this face slides on the lower retainer of the pump.

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Pressure side.

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Pressure area of pump.

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This is the suction side, the only real physical damage.. and I wouldn't at all consider this a problem in operation.

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