2006 Toyota tundra fuel injector clogging issue

Hi everyone, I have a 2006 Toyota tundra double cab 4wd. Truck has 270k miles on the dash. I have been having a reoccurring issue with clogging my fuel injectors. I put a brand new fuel pump back in July since the old one was not making enough pressure to run well. Replaced that and has ran fine for the time being. I keep getting cel lights come on for bank 1 and 2 being too lean. I took the fuel injectors out, ultrasonic cleaned the ends of them and used fuel injectors cleaner and sprayed through them. And what do you know the cel went off. Then a week later same thing happened, cel light came on, cleaned injectors, light went off and ran much better. Well it’s doing it again. I know that the pump has the built in filter so I’m unsure how it keeps clogging them over and over. I have used fuel injectors cleaner in the tank multiple times and that helps but hasn’t stopped the issue. Do you all have any idea what could be happening? Could the fuel line itself be breaking down? I have never had this happen on a vehicle before.

 

Big thing you need to understand is, "too lean" codes are the upstream O2 sensors reading the unburnt fuel and oxygen content coming out of the cylinders via the manifold. That's the key to resolving lean codes - figuring out "why": Is it a fuel delivery issue? Is it a sensor issue? Is it a vacuum issue?

If the sock is properly installed on the pump body, you shouldn't be getting anything large enough to clog the injectors, I think it's just a fluke that ultrasonic cleaning is helping. The more likely issue is one of the following:

• You made the mistake of buying an aftermarket pump, and it's slowly failing to produce the volume of fuel required, it may have been defective right out of the box (many aftermarket parts providers these days don't QA/QC their parts, that's what they sucker consumers for!)
  • You can use a fuel pressure kit to test at various RPM to ensure you're getting at least 38-40psi to the rail at various RPM would confirm/prove if the pump is failing to produce
• You're still on the factory MAF, and it's tired, reporting less airflow than is truly incoming to the engine, so the ECU is pumping less gas into the cylinders, leading to 'lean' condition
  • Could also be that you're making the mistake of using an oiled filter, and your MAF is just dirty, and needs half a can of MAF cleaner emptied over the sensor in the MAF.
• Your fuel pressure regulator could be dying, or the vacuum lines linked to the regulator are detached or cracked.
• Many fuel lines are quick-connect, and having one ever so slightly not-clicked-together can cause this also, this would primarily be on the delivery side, between the pump and fuel rail

There are definitely a few other things it could be. If you have a scanner that can read realtime stats, like fuel trims, it could help to isolate what's going on.

The injectors are a red herring here. Tell us more about your MAF's history, and more about the fuel pump you bought. And if you're using an oiled filter or K&N hot air intake kit (or similar) instead of the factory cold air intake our trucks came with.

 

As far as sensors and vacuum lines go, I have replaced the following with oem parts- maf sensor, both upstream o2 sensors, new fuel regulator and fuel dampener. Smoke tested the intake and not one bit of smoke leaked out anywhere. I understand these truck like oem parts but I financially can’t afford an oem pump. I tested the pressure at the rail and get 40psi at idle and WOT and anything in between. Why I say it probably not electrical issue like a sensor problem/fuel pump because after I have cleaned my injectors, my fuel trims read dead zero for at least 75 miles. If the pump couldn’t hold up it should be saying I have high fuel trims regardless whether I cleaned them or not right? My live data readings are 3.3volts for upstream o2 sensors. I failed to mention that this truck sat for almost 3 years before I got it and I have put 2 full tanks of gas through it. That’s why I thought it was junk\corrosion in the fuel lines. Tank looked spotless when I replaced the pump. I did drain the bad gas out completely. My live data readings are for everything except fuel trims are reading right.

 

Not sure what to tell you, but you should be at 44psi, ideally, especially at WOT. Some engines can handle as little as 35psi, and I'd like to see more than 38-40psi at idle, but at WOT, I'd prefer to see the full 45psi+. And something as simple as, "someone didn't tug test the fuel line quick-connect after connecting each one, so you have a slight reduction during high-flow events" could easily be the reason why.

As far as OEM parts goes. You say it's overpriced. How much have you paid thus far on everything else trying to whackamole this problem? "Buy once, cry once" is my motto. This is the sad world we live in these days: Aftermarket parts suppliers (I won't call them "manufacturers" anymore, most don't mannufacture shit, they just rebrand from bulk warehouses) have learned people will choose to pay less for inferior parts that aren't tested. They slap a lifetime warranty on it, and put you in charge of quality control. If it's dead, you'll be back to get a replacement.

There are two hard-to-replace parts you really need to use OEM, or at least the OEM supplying company: Starter, Fuel pump.

Look, I'm not saying an OEM fuel pump, or a Denso brand fuel pump, is going to solve your issue. But the things I outlined, and a few others, are the main causes. Sure, it's possible the fuel resistor or some other circuitry part is causing the issue, so the pump isn't getting full power, thus the pump isn't hitting full stride/flow. It could also be a line that's not fully snapped (we've seen it a few times before on here, but most cases, people claimed not smelling gas). It could also be that rodents were nesting and chewing things on top of the tank, and have compromised the power wiring. The hard part about trying to help people on a forum like this is, simply that, not being there in person, we're limited on what we can known and understand about the situation.

If it's really irking you, you can pay the dealership for 1h-2h of diagnostic time for their technicians to dig into it. But I think you'll find similar to what this guy was told. Toyota tech informed the guy they want to see minimum 44psi at the rail. Low fuel flow pressure causes lean codes.

 

I’m not buying clogged injectors as the problem here. You have both banks reading too lean, so look at more global issues, things that affect both banks. MAF, intake up to the TB, the seal at the TB, fuel pump, ECU etc. the O2 sensors are best replaced together both upstream and downstream so that the comparison is new to new, not new to old potentially worn out sensor. What were the codes displayed exactly? P0 what? Too lean can be not enough fuel delivery, but often times is too much air delivery, or unmetered air is entering the combustion chamber. That would happen after the MAF, but before the individual intake runners.

 

Thank you shifty for that input. I might break down and get that OEM pump if that seems to be the issue if absolutely need be. I’ll check later tomorrow and see what that psi is. I had no idea that it was so particular about the PSI reading.
I can inspect the wiring and gas input hoses and see if something is not right.

 

Probably not the issue, but do you get gas at the same station every time or do you mix it up? I had dirty gas from a station clog all the injectors on a brand new Tacoma back in the 90s.

 

In regards to knabores, the codes were p0171 and p0174. My maf sensor reading is 5.0 at idle when up to temp and I replaced this with an oem one back in July. I not only smoke tested the intake, but I actually plugged off different parts of the air intake system and checked to see if I can get a leak anywhere to find anything. I replaced practically every single rubber vacuum hose on this and even after that checked for vacuum leak with my smoke machine again. Again found no leaks. I have really tried to rule out vacuum leaks as being my issue. I have cleaned my throttle body with the specified cleaner. I did replace both upstream and downstream of two sensors at the same time. I replaced both exhaust manifold gaskets as well, and those were actually leaking in which I thought this was my issue, but it apparently wasnt big enough of a leak to matter.

Only reason I suspected fuel issue-the truck ran amazing after fuel pump replacement. Idled great, revved up smooth, and fuel trims were reading zero across the board. As the issue arrived of it idling rough and the bank 1 and 2 too lean codes, the fuel trims were crazy erratic. Jumping up to 44.5 on long term then back to -7. They are all over the place. But my maf sensor reading was reading what it should. Upstream o2 sensors reading 3.3v. But shifty might be right on the fuel pump so I’m again going to check that psi reading tomorrow and I’ll be back to update.

 

And yes Upshot, I go to the same gas station near my house for years. I did see someone on these forums say they got bad gas with water in it before so that is a consideration.

 

Just for the hell of it, fill it up at different top tier station and see if there's any difference. Probably not the problem, but doesn't hurt to eliminate it as the problem either.

 

Most EFI engines on vehicles I've owned (which can be counted in dozens, I'm only a moderate car whore) wanted at least 30-35 to the rail to be able to idle without stumbling. Others on here have reported being able to idle our V8s without stumbling at 38-40. A lot of people on here and 1h8mud forum will tell you Toyota calls for 44-45psi at idle for ideal performance.

If we look at the FSM, for the 2UZ-FE V8, service specs, it calls for 38-44psi (see below). I'm attaching pages for 2005-2006 Tundras to the end of this post for the fuel section, as an attachment. It will tell you all the things to check.

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Bottle of HEET (red bottle) would suss any water out, rapido.

Read the 'ounces per gallon' on the bottle, and factor in that when your fuel gauge registers "E", you still have roughly 4 gals in the tank.

That said, I don't think any fuel treatment or injector cleaner is going to do a better job than your ultrasonic cleaner. It may clear out the lines, I guess, but ...

Sitting for that long, especially if you're in salty areas, could lead to corrosion of connectors. Especially if you have or had driver A-pillar leaking. Or, because the fuel pump wiring has a connector somewhere around the drivers seat, inside the cab IIRC, water puddling in the truck could lead that to rot out.

 

I will fill up at a different gas station tonight and I’m pretty sure they have Heet there which is helpful. And I see what you’re saying about fuel psi. I’m definitely going to check that out more throughly as well as check the other resistance readings from the manual.

 

By OEM fuel pump we mean Denso. I think this is the right one (but your profile doesn't provide enough info to be sure...V8, right?). ~ $122 doesn't seem like too much in the grand scheme of things...

https://www.densoproducts.com/denso-950-0100-fuel-pump-and-strainer-set

Or ~ $109 plus shipping

https://www.rockauto.com/en/moreinfo.php?pk=2143066&cc=1432861&pt=6256&jsn=525

Or $132 with free shipping...

https://www.summitracing.com/parts/...b__CsWOz-Ob3tBlWin57fYxCuOP0KN7sPso5p5BbU59Hs

 

Those two codes are most often associated with, you guessed it. Fuel pump. Yours tests decent, but to @shifty` s point, maybe not up to OEM snuff. You've ruled out most of the other possibilities in vacuum leaks and MAF and TB issues sounds like. May be time to invest in the OEM (Denso) fuel pump.

 

I realized when I was looking up oem fuel pumps I was looking at the whole assembly price from Toyota which was $545. Didn’t even realize I needed just this part y’all mentioned to replace in the assembly basket. That’s something I could afford, I’m finally getting to testing today so I’ll probably pull the trigger on the pump.

 

You can just buy the pump. Denso made. www.densoautoparts.com to look up the part number.

Just don't be stupid: Don't buy it on scAmazon, fleaBay, etc. (big risk of authentic-looking counterfeit or grey market parts). If you must order online to get a good price, order it from RockAuto, or order from Summit Racing and have them pricematch to Rock Auto. Both are solid, inventory-verified sources.

 

thanks for the info on that. If it worked, I attached the photo below of my fuel pressure reading… maybe the first time I checked it was a fluke or something because I got 44 psi at idle, and then I let the truck get up to temp and at wide open throttle it’s still read 44 psi. When I started the truck up my fuel trims for both long we’re at 44.5, and as it warmed up and got all the way up to temp that number came back to zero, got no idea what to do at this point. It’s so frustrating when I feel like I can’t get any consistency out of anything.
When I was driving the truck yesterday, I was able to make it about 5 miles with no issues and then all of a sudden, my fuel trims were soaring in the truck started bucking again, as I let off the pedal my fuel trims went to zero, made me think oh a maybe it is a vacuum leak. But correct me if I’m wrong if there was a vacuum leak, this thing should be running the fuel trims high immediately when I accelerated leaving the driveway correct?

 

Don't bother reading fuel trims until the vehicle is warmed up. What you see after the truck warms is reality. I can post a video that'll help understand that stuff, if you need it. Car Care Nut has one that I found pretty helpful.

But the symptom you describe with fuel trims soaring is not normal. I would suspect a vacuum leak, or you have a bad upstream sensor. Was it trims on both bank 1 & 2 going nuts? Or just one bank? That would be helpful to know.

That pump is fine, dude. IMHO at least. Fuel trims tell another story, and I think is your big "AHA!" lead here.

 

Both long term fuel trims were up at 44.5, had a pretty rough idle, probably the worst I’ve actually seen in since I got the truck running. It shouldn’t have a rough idle on startup. I guess I'm going to check every vacuum hose over again and see what I see. My upstream o2 sensors are reading 3.29 volts at operation temp. I had a week ago went back and made sure that I was getting a proper 12 V to both upstream sensors as well in which I was. But I can’t rule that out just yet. I guess I’ll start looking for a leak.

 

Both fuel trims ... huh. So it's impacting both banks. So not bank specific.

And this existed before you replaced with a new OEM MAF?

When you cleaned the throttle body, did you spray anything into the throttle body?

Have you checked the throttle body actuator harness for signs of anything weird?

 

Correct. I still had high fuel trims before I replaced the sensor. If I remember correctly, my bank 1 long term was reading 44.5 and bank 2 long term was reading 20.5. Now both are reading 44.5 as of today. As of right now, I just got done taking off every single vacuum line on here and checking for splits in the hoses and both plugging each end and making sure that no air is escaping anywhere through it. I only found a small crack from the PCV valve hose in which I had extra hose so I repaired that one.

 

And to answer your question about the throttlebody, I followed the instructions on the back of the can in which says to place a rag under the throttle body and slightly open the butterfly and spray around it and wipe off carbon deposits. And I have not checked the actuator harness. The clip on the plug broke on me but seemed to seat well. I’m going to check this out right now.

 

Alright so I checked the actuator harness and I see no signs of wear and corrosion in the plug. I started it up and with my scanner said throttle position at idle is 17.3%. Does that seems normal?

 

Yeah, future reference, never spray anything into a throttle body, except maybe starting fluid. You can damage things. But if it existed before cleaning, that's not your problem right now. Saturate a rag, then wipe out the gunk. And don't slam the throttle plate.

I'm at a loss. If that FT number is positive, especially when idling, it means the ECU thinks it needs substantially more fuel than what it actually needs.

It's getting that number from somewhere. Unless my brain is scrambled - it's been a long F'n day for me already over here - Either the upstream O2 (i.e. the air/fuel ratio) sensors are telling it "you're burning lean!" and it's dumping more gas into the cylinders, or the MAF is telling it there's a higher volume of air incoming than what is reality, or the actual position of the throttle plate is much less than what the ECU thinks it is, for example. I'm sure there are other potential causes, but I'm tossing out thoughts about what could cause it.

The other possibility is, of course, the O2 sensors are correct, and everything up to the throttle body is not leaking, there's just some sort of vacuum leak that's allowing the engine (which is one big air pump, sucking air in, blowing air out) to pull in extra, unaccounted for air, it's combining that air into what was already a good air ratio, leaving you with too much air in the exhaust ratio, which both sensors would be picking up and reporting "need more fuel!". But that would require an event that would allow air into both banks, substantially. Like, the intake gasket was shot? Would be super wierd for our 2005-2006 trucks, because the intake just uses a basic formed rubber ring that looks almost like the old plastic 6-ring beer can holders, only black and more o-ring like.

 

PS some numbers for you.

Note the RPM and temp at the time these were taken. Engine was warm with both. My LTFT is almost always higher on bank 1. STFT usually bounces between 0 - 1.6% at idle (typically 0) and my LTFT is typically around 3.6 - 4.7 on bank 1 and 1.2 - 1.6 on bank2. Both fuel trims are virtualy static/unresponsive for the first 1-2 miles of driving.

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This cap is before I added the RPM in (since that's kinda important to know with FT), but it was taken within 60 seconds of the 1st pic above. I was idling at a stop light, after driving for 15-20 minutes, to capture these numbers, after taking the pic with the "coolant temp" above.

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Last but not least, check this reply #2 and the videos in it. Watch the videos. It will give you some ideas and open your brain to thinking thru your results logically, so you're not having to keep coming back here for info in bits: https://www.tundras.com/threads/false-tps-readings-causing-lean-codes-06-4-0-v6.160922/#post-3974128

Also, look over your hoses and such carefully. Make sure your air filter housing is properly sealed. Check all the clamps and rubber joints on your intake tube and throttle body to make sure they're good.

Moreover, check all four bolts on your throttle body to make sure they're tight! Again, think about this from the perspective of, "where could extra oxygen be getting into the engine between the top of the air filter and the bottom of the intake? Trace the path. Check all vacuum hoses and ports. Check all bolted on items. There's a trick you can do with MAP gas or brake cleaner, to spray around the edges of the intake and tube, and check for surges. If the engine is pulling in outside air thru the intake, and you're spraying something that will act as a fuel around that opening, it will get vacuumed in and burnt, and you'll hear the engine surge or die.

There's always the possibility it's a sensor at play. But again, the chances both upstream O2 sensors would be bad at EXACTLY the same time? Possible, but highly improbable. The only other thing that makes sense, to me, would then be: Leak. Bad MAF. Throttle assembly.

 

Gotcha, I won’t do that again on the throttle body. You thought exactly what I thought about the intake gasket. I was thinking “it has to be leaking somewhere” but my smoke test(done it 3 times because I was having vacuum leak symptoms) told me no leaks anywhere. I used carb cleaner and SOAKED around the intake trying to get a rpm rise and got nothing. I also had the thought like you of air coming from saying anywhere not in front of the throttle body like the vacuum line for the brake booster. This was my only guess is where the unmetered air could come from. I’m going to get the truck up to temp and compare my numbers to yours and see what’s different because I too am at a loss rn. I’ll watch the videos as well. I will go check all the simple stuff again like you mentioned especially the throttle body bolts. I’ll keep looking like you said follow the path of air flow and see. I’ll update asap. Thanks

 

Have you checked the intake hose that goes from the brake booster over, and any joints in between? I'm not sure if smoke would reach that far, but it's a gaping hole in the system that would potentially produce enough air to cause this.

The only other explanation I don't think has been covered so far would maybe be bad ECU? But it just doesn't make sense to me, honestly.