2UZ-FE High Long Term Fuel Trims

[Queglay]

by PQ do you mean Part Souq? yeah I use my vin in there and in Amayama. What I described looks like a glitch because the latest part id (7702060392) does not show up as compatible when searching for my vin. But I asked my local toyota dealer for a quote using my vin and the part number they came up with was 7702060392. Do you have a link to the toyota web portal so I might verify independently though? I'd like to learn this for the future, cos partsouq was inadequate here with my vin.

I'm going to replace the whole assembly, since the part ID has been updated twice since mine was manufactured, and it was probably a bad design. There could be any number of issues with the thing so if we do this job and theres an opportunity for a complete refresh I'll take it for reasons like this eg:
plus its nearly 20 years old now.

 

[2001LC]

Yes, PQ!

Toyota Parts portals I use, are in USA. They'll do you no good, since we don't have 4.7L 2UZ-fe VVti in 200 series. Your PN # doesn't show anything in USA portals'.

Yeah, not bad idea to replace the whole assy.
Only other paster you'd is tank seal. That, and engine room fuel filter and its green locking clip. Make sure to transfer the white hose bracket, to new fuel filter.

Parts number (PN#) changes, are mostly due to change in supplier, cross platfroms standardization and to lesser extent correcting a defect in materials and or design. Id defect, there's usually a TSB. Some parts I see, have 6 or more PN subs.

 

[Queglay]

Fuel filter arrives in the next few days with Charcoal canister. I'll replace those first. Pump is going to be a few weeks away.

 

[jerryb]

where you able to find the denso stock pump? Hate to say it, but I see a lot of tail chasing.
Short the resistor on the car side of the harness. Worthless item imo.
TS to run the fuel pump and check pressure.
Check leakdown.
That's it for fuel pump. Most expensive thing here is a working techstream unit.

Graph idle AFR and narrow band O2 voltages.
Graph same full throttle uphill 5th gear in a snowstorm both ways.
Bluetooth obd2 and free app. You could graph MAF volts also. Easy to just swap with a friend with any toyota 5 wire. and check for changes.

 

[Queglay]

I bought the latest genuine pump recommended by my toyota dealer, on its way now. Not sure if it's denso.

https://partsouq.com/en/search/all?q=7702060392

How would I identify where that resistor is? Are you referring to a 200 series or 100 @jerryb ? In the FSM it says that a full 12v to the pump can burn it out and to limit doing that for 10 secs.

I'm really out of luck getting techstream working. I cannot run the active test at all on the mac VM (crashes), and the windows VM on this forum wont even boot on my AMD (probably architecture issue). Don't have the spare cash to get another machine at the moment.

Replaced original fuel filter yesterday with new genuine one, not expecting anything - 18 years old so it needed to be done and I wanted to see. it didn't make a change to FT's. actually fuel pressure dropped from 28psi to 25psi, not sure if thats noise in the reading from my OTC gauge or if its air in the system after replacing the filter. I'm guessing that will go away over time. Curious to do a back flush but I dont have an air compressor.

I might appear to be tail chasing, I live on a tiny island with a 40kmh speed limit and trying to resolve what I can, chipping away at this because the past 4 mechanics couldn't figure it out when the car used to live in a big city with way more resources. I've gotten further than they did now though and eager to learn from everyone here.

 

[jerryb]

all this assuming the 200 with the 4.7 engine bay and fuel set it is the same. I've never looed inside a 200 with the the 4.7vvti. I always wonder about those when I see them.

the full 12vdc they're talking about is because the battery is going to die quickly checking it in the car without running.
The pump itself runs regulated voltage at 14.2vdc just fine.
Dry checking it out of the car will burn it.
Checking in a bucket of fuel isn't a great idea either.
Opening the cover and checking it at the pigtail on top of the cover with battery leads is fine. Hopefully people stop there and question safety but realize that it's all submerged and works just fine. Doing this for a flow test is almost worthless. You might as well just replace the pump and filter.

yes 100 series, and any series really. Lots of 100 people don't use the resistor. I'm not saying its better not to have it working. I just personally haven't had mine in the car for a long time. In the end it's just another failure mode, but easily defeated broke down on the side of the road. It's located on the pass fender well, 2 wire connector. It has fins on it and will burn you. It looks like a big chunk of aluminum.

Thing about techstream- good for starting out, used it many times. After a while it's clear there are some great active tests and it's worth it for that, but mostly BT OBDII devices can get you 75% of the way.
I do use the posted VM in the techstream thread on win10 machines. I probably haven't used it in more than 12 months in the LC. I do use it on a LS460 frequently.

I was asking about the vvti fuel pump because they really aren't available anymore (easily) I was thinking there are enough Australian LC people that they might have a cheaper alternative. I haven't kept up with denso's supply problems.

Tank pressure and high heat aren't necessarily related to high trims. Solving the high trim won't auto fix the high fuel temp thing, It might help, but I wouldn't gamble someone's money on it.

I don't subscribe to the having high fuel trims is detrimental crowd. Design is +-30 before a CEL.
I continually have +10-15 long term trims, and don't care. Still is get 320 miles a tank. I have a different- moved intake and two batteries, no cats and narrow band emulators, so I only look at the afr's (front sensors- wide band)
The SAI non sense is way more irritating and problematic than FT's- another worthless system best deleted.

it's a journey, good luck.

 

[Queglay]

@jerryb there are genuine fuel pumps on part souq - there are plenty. Price is a 1/2-1/3rd of Toyota's Australia tax. The price gouging should be illegal.

I dont expect fuel tank pressure to fix this problem, but it could influence premature failure. It's just the pressure is extraordinary with 273L tank and it needs to be fixed. The blockage is adding maybe 2-3% to the fuel trims, once that is fuel vapour instead of air I expect it to be a small improvement. I also want to rule out tank pressure causing cavitation or affecting pump operation as a cause on any replacement pump first, so charcoal canister is going in today.

You say "I don't subscribe to the having high fuel trims is detrimental crowd. Design is +-30 before a CEL."
The way I see it, I also don't think things matter too much if they are balanced, but mine are not, and since bank 1 is getting fed more fuel continuously, its doing more work than bank 2 and affecting compression and balance over time.
The thing about FT's generally is instead of the fuel map lookup table getting its first assertion correct to achieve stoichiometry, we are relying on a delayed loop to make corrections after the fact. That error is especially inaccurate in a dynamic situation like varying acceleration relying on STFT which has lag. I can't imagine how much more responsive things will feel if I can get FT's to within 5%. So I see FT's more as an opportunity to do some good diagnosis and preventative maintenance on a car I want to last a very long time. Indeed they are a blessing for me because I got to learn all this about my engine's state by figuring out why. I'm also getting DTCs every few months so those have to go!

In the FSM, this suggests there is no simple resistor for the 200 4.7 vvti. the ECM sends a duty cycle signal to the fuel pump ECU and that controls the pump output. You are right to get to the point where I'm attaching leads to the fuel pump I may as well replace the pump. I have an authentic spare coming and the original is 18 years old (only 140,000kms though) so I'm going to replace it. Pulling out all the draws and seats will be fun but beats paying someone 140/hr to do that. I sure hope the manual is right when it says I need 38-44psi at idle and that isn't the pressure needed for WOT. The parts cannon is running at about 1500AUD right now but all on things that make general sense at least. Think I need to buy a floor jack to drop the tank.

 

[Queglay]

@2001LC that data point you were after - the old canister weighed in at 2.235, and the new part weighs 2kg. 10% is a fair bit of goop.

 

[Queglay]

I just did a test that I think proves my theory- that bank 2 gets starved more (higher FT's) than bank 1 in low fuel pressure situations the lower it goes because it's further along the delivery line.

Here we see:
- At idle there are multiple pressure states after startup which we can observe in my scenario which looks too low. FSM states the fuel pump in the 200 series 4.7 has 3 different duty cycles.
- When fuel pressure drops from 29 to 26psi a few minutes after engine start, total fuel trim increases, and bank 2 worse than bank 1.
- For a given drop in pressure there is a greater difference in fuel trims between bank 1 and 2, with bank 2 being the worst. This is proven by the three different pressures we observed, 29psi, 26 psi, and 20 psi, each with a greater difference in total fuel trim between bank 1/2.

 

[2001LC]

If you're assumption correct. That when fuel flow or pressure below optimal, we see BK2 leaner than BK1. Would be nice clue, in diagnostic tool box.

But may not be a fair assumption:
Fuel injector, condition unknown.
Fuel pressure regulator, condition unknown.
Fuel pump, pressure test fail.

In theory, the fuel rail is at a constant pressure when all as should be. There's more fuel available in rail than needed. Trying restricting fuel flow, on a 4.7L that all systems known to be spot on, would be next step.

Note:
The 4.7L VVti 2006 100 series, I referenced bad gas rust (pictures in this thread) in tank and filter. Had BK1 running leaner than BK2 (HWY speeds).

 

[Queglay]

its true, fuel pressure should be the same throughout the entire system, but that only can be true if the pressure is high. The lower the pressure, the greater the differentials in the system.

For the regulator - when I did a leak test for ten minutes, fuel pressure did not drop, maybe 1psi max.

My fuel pump full assembly delivery arrived, with the threaded ring cap and gasket. I emptied all the rear of the car, was hopeful that I could remove the cap internally off the body and replace it but the hole is not large enough, so the tank needs to be dropped. Figured I'd clean the area with my girlfriends steam cleaner (dont have a big air compressor tank), wow the steam cleaner does a pretty darn good job, might apply it to the hard to reach areas in the engine bay some time.

To drop the tank, I don't have stands or a floor jack and buying all that right now would be a about 4x more expensive than getting a mechanic to just drop the tank and do the job for me, so its going in to him in 12 days. Fingers crossed that things improve.

 

[2001LC]

FPR test, is first up (engine off). If it fails, we correct. Next is fuel pressure test (engine running). If fails we correct. Last up is leak down test. A fail leak down. Is fuel injector leaking, in excess of limits. Of which symptom is, long crank to start.

I do see what you're saying. In that if, fuel pressure not up to optimal pressure, in fuel rail. We may see uneven fuel trims. With BK2, being down stream. May have less available fuel, since BK1 closest to entry fuel point. So BK2 running leaner than BK1. I'll be on the look-out for this.

1. BK2 leaner than BK1.
2. Fuel pressure test: Pressure below minimum required. Or find fuel system issue, resticking fuel flow to rail.
3. Then correct fuel issue. I should then see BK1 & BK2 fuel trims come in line/equalize.

Interesting. Your, top plate looks like a white plastic. We have metal. Which has metal with 8 small bolts. With gasket sold separately.

Can you post a picture of your new fuel pump assembly?

Does your model FSM, say: to remove fuel pump, drop the fuel tank?

 

[Queglay]

Yeah the FSM says to drop the tank. The fuel pump diameter is too big to fit in that port. Seems so unnecesary.
The pump assembly is in the garage but looks exactly like this. Theres no visible fuel sock like yours, perhaps it is internal. I will look inside the old pump when I have it.

 

[2001LC]

Issue I've with U.S.A. 200 series. Engineer's apparently, never swung a wrench on them.

 

[Queglay]

Seems like my new mechanic found a vacuum leak - the throttle body needs to be replaced. Will get a video soon. Not sure how the fuel pump was a red herring because fuel pressure looks awful to me, maybe my otc gauge is no good.

 

[2001LC]

Your CC, was only a little overweight (10% over). I see ~25% over, on really bad ones.

IIRC, you did not get a fuel pressure regulator (FPR) test. Which is first, in sequence. But, what we see on those when bad, 9 out of 10 times. Is pressure goes over max of 44PSI. I just had one look okay while battery low at 12V, at 12.7V it was over limit at ~48 PSI. 4PSI was not much over, and could be gauge calibration. But when i installed new FPR. FPR passed the test. Which indicated my gauge was okay.

Your fuel pressure test, was a fail. It is possible, the new gauge was out of calibration (bad). But not likely, when new out of the box. I'd return for a new one and see if result change. Or have your new mechanic do a fuel pressure test, including the FPR.

I don't recall if you ever check fuel filler, or replaced.

Throttle body:

I, mention your throttle body earlier in thread. When you first posted a picture of your engine. But only because, I notice boot missing on wire harness. Which would indicate someone had done something in area. That boot, can not just fall off. In fact it would be very difficult to remove, unless wire housing block removed from wires.

I have never seen one of these VVTi throttle bodies go bad. But it appears, someone work on yours, for some reason. They may have not, replaced gasket when they did. But, I would have thought your smoke test, would have revealed a vacuum leak at TB.

What test did he do, to find vacuum leak at TB and where is leak?

 

[Queglay]

Well when i did the smoke test, i didn’t turn on the ignition. They had to do that to open the throttle and the leak is between the plastic part and the metal, not the gasket.


Turns out they were wrong though, that issue must be minor because I got them to replace the fuel pump anyway and now the fuel trims are within a good range, just slightly rich but in spec. So success! They said they vacumed out some crap that was in the bottom of the tank, so it was probably bad fuel that caused it.



I’ve got questions about the oil they used though, I can barely see it and it concerns me.
Oil change very thin - https://youtube.com/shorts/J60DnbiHVyQ?si=GYYtdGxJRHirt3vr

Also to top things off they told me to fill the tank and pour in some wynns injector cleaner they gave me, well that overfilled it again. So pissed. Can I save my brand new charcoal canister or is it toast? I tried to get the overflow out as quickly as possible.

Overfilled when adding injector cleaner - https://youtube.com/shorts/lIu-FaryOs4?si=22ZVXPz8r4gPSOBJ

The good news though is the fuel trims are healthy. I’m keen to see where the fuel consumption is now.

 

[2001LC]

So it was as suspected, and as the fuel pressure gauge indicated.

If you haven't yet. I'd replace that fuel filter before driving, more than to just get some gas out of that overfill fuel tank.

In post #43, you see particles in fuel tank. What that is iron, is the solid remains from chunks of rust. Which comes from, old metal fuel storage tanks. More than those remains seen, entered the fuel tank. As fuel sloshes around. It grinds down rust, leaving the larger heavier solid particles behind. The microparticles are taken up by fuel pump. Which is hard on pumps, moving parts. Microparticles, then travel to fuel filled. In post #43, you can see how very contaminated that fuel filter was. It was the worst, I'd ever seen.

Rule of thumb: Avoid old filling stations. They are very often still have the old metal storage tanks. In Denver, CO. USA, my home town. The state keeps a record of which type of fuel storage tanks the filling station have. So I can check online for which filling station is safe. The tanks install for about last 30 years, are all plastic.

Bummer on the overfilling of fuel tank. Did some get in CC, most likely! You'll likely be fine. We see the CC get bad. When overfilling is repeated, time and time again.

Interesting smoke test on throttle body. I can't say if normal or an actual leak. Since I've never look into or even thought about before. I've not even torn down a 4.7L 2UZ-fe VVTi throttle body. But as I said. Someone for some reason, has serviced/worked in area. Evidenced by the missing boot. Likely someone in the past, chasing fuel related issue, as you've been doing.

 

[Queglay]

Indeed, im amazed they found that vacuum leak. In any case it can’t be too bad since fts are around -5%. I will get a replacement throttle body sometime though. Now that this issue is solved I need to clean the sunroof drains and upper and lower control arms. Do you think that oil looks suspiciously thin? I’m very happy we figured this out and thanks for replying back to my questions @2001LC .

 

[2001LC]

Indeed, im amazed they found that vacuum leak. In any case it can’t be too bad since fts are around -5%. I will get a replacement throttle body sometime though. Now that this issue is solved I need to clean the sunroof drains and upper and lower control arms. Do you think that oil looks suspiciously thin? I’m very happy we figured this out and thanks for replying back to my questions @2001LC .

I really could see oil in video. But when fresh oil in a clean engine. Can be very hard to see.