2000 4Runner needing injectors for 3rd time

As the title states, I'm headed towards my third set of injectors in the past year. Last May I threw a code for P0172 (bank too rich). I bought the 4Runner in 2018 with 201k miles on it, and the private seller had put a full set of new injectors in it. When I pulled them out last May, they looked like a cheap set, probably from a box store or Rock Auto; something India made. I can't blame them I guess since they were selling $5k vehicle, and a garage did the work so it was probably out of their control. It now has 251,xxx miles on it.

I use genuine TOYOTA parts from Ourisman Toyota in Richmond VA. In the past couple of years I have replaced:
- TPS
- IAC valve
- all new Denso coils
- Sumitomo plug wire set
- New NGK Plugs
- Cleaned the MAF sensor
- Magniflow cat-back exhaust
- new fuel pump, pick-up tube, sock filter, and sending unit
-the fuel filter back around 2019

Last May when I did the injectors I replaced the valve cover gaskets, PCV valve, fuel pressure regulator, O2 sensors, and the engine looked excellent inside given the mileage. It still doesn't burn oil and there are no signs of coolant issues. I used Motor West Performance injectors for the replacement. The repair went well, it ran great, my MPG went up a bit, and the code went away.

5 months later in October I got a P0172, again, and MWP sent me a new set with new intake plenum/manifold gaskets, and fuel rail banjo bolt seals. Again, the code went away and it ran great. I'm getting quite good at getting the injectors replaced quickly. I'm very careful inserting the new injectors using the provided lubricant, to not cut the o-rings, and also careful to not be sloppy with getting the lubricant where it doesn't belong.

The other day my Runner stumbled a bit at high idle after starting, and it surged a few times on me. I now had a good idea what was happening as this happened the other times as well. Yesterday my LTFT was is at -32.xx% and it actually died on my at my house, but it started right up. The LTFT was in this range the other times as well. If it does through a CEL it has only been for the P0172. Every time after the repair, my STFT and LTFT go back into the -10% to +10% range, and I monitor it for about 2 weeks until I feel confident its fixed. In that time it runs fine, and get 17.5-19.25 MPG.

Am I just having bad luck with "remanufactured" injectors? I know MWP has a good reputation, but I can't come to any other conclusion other than I keep getting injectors from them, and at least one fails after a few months. I know it may not be likely given their reputation, but it's also not impossible, and this is getting OLD. I read on the IH8 Mud forums that Denso fuel injectors are not truely rebuildable because they are a sealed unit. They can be cleaned, screens replaced, replace o-rings, and tested, but they can't replace the solenoids, coils, pintle, return springs, or valves. If this is true, this is a great point and piece of knowledge.

page 2, post #24
https://forum.ih8mud.com/threads/refurbished-fuel-injectors.1225257/page-2


The reason I believe that its a bad fuel injector, and at this point not another issue, is that new injectors always fix it with no lingering problems. I would think that if its related to the ECM, bad wiring, or bad Toyota fuel system replacement parts, the issue would persist immediately, even after new injectors. All the other data from the IAT sensor, MAF sensor, TPS sensor, Coolant Temp sensor, and 02 sensors are correct and with in a healthy range.

I would like some thoughts on this. MWP has a Million Mile/Lifetime warranty on their injectors for the 5VZFE, but I'm very tempted to just get a new set of genuine Toyota Denso injectors from Oursiman Toyota at $166/each, and hopefully be done with this. Yota Shop has Aisin injectors that are claimed to be new OEM (I know Aisin makes good stuff) for a much cheaper $89.37/each, but I'm wondering if I need to stop cheaping out on this, bite the bullet, and just go new Toyota injectors. If this happened again after doing so, I would be confident that there is another issue. I just don't know what that might be if a new set of injectors always solves the issue.

For fun and general interest, I've attached a few photos of what the heads look like once the covers removed; I was happy with what I saw. I'm liking Valvoline in our Yotas, and I'm currently running the Valvoline Restore and Protect.

View attachment 268439

View attachment 268440

View attachment 268441

View attachment 268442

View attachment 268443

View attachment 268444

View attachment 268445
Try this company. https://www.rcfuelinjection.com/
 
Those brown injectors are known problem-children. A good rust free 4Runner of this era is bringing a kings ransom, at least they are where I live. Easy for me to say but I'd bite the pillow and buy new Toyota injectors and be done with it, this particular vehicle is worth it.

Those brown ones were the replacements the seller had installed. I tried looking up the name, it was something like "Aaraan". It's not good when a lot of sketchy Temu type ads and sites pop up for the brand name.

Bite the pillow indeed. $1,146.00 after tax and shipping for everything I need. Hopefully WMP gives me something of refund, or a new set to sell.
 
It's a 2000 4Runner. And high mileage. How much do you want to spend? Get injectors from Trav.

Have you checked the frame for rust issues? My brother had to junk his 2004 4Runner as the mechanic would not put it on a lift due to extensive rusting. I think there were class action law suits due to the Dana frame.
The recall was for Tacomas. The 4Runner frame was made in Japan.

They still rust. Ours (2001 with 151,000) was rusted on the inside of the frame next to the fuel tank. Costly repair. Many of the used trucks I looked at had frame repairs.

We use OEM for a lot of stuff (like lower ball joints) but haven’t had to replace the injectors yet.

2021121821555158-5196348032011093322-IMG_1225.webp


2021121821571695--3703822704870115569-IMG_1240.webp


2021121821571695-1464369737178582663-IMG_1241.webp
 
Why would a company come up with and sell a frame repair kit designed for several models of the 4Runner if there was not a problem?

Look at autorust.com.

Because they saw a market for owners of neglected 4Runners.

I owned a 3rd gen 4Runner for 22+ years. It was operated every winter on Salt encrusted roads, and spent time every year on the Bonneville Salt Flats. When I sold it, it was rust free. How? I washed the Salt off (including the undercarriage) regularly.

The day I sold it doing an in-and-out through a dealership.

IMG_20191023_182902.webp


I recall a neighbor who bought a Mercury Mountaineer (Ford Explorer) at the same time I bought my 4Runner. After 10 years, his Mountaineer was a rusty hulk, it's frame and body were ready for the scrap yard. In fact it was scraped. It had also had many major mechanical repairs. My 4Runner in over double the years of service, had only needed a $20.00 hydraulic hose, and an hour of my time to replace.

A 4Runner is very reliable mechanically, but if Salt isn't cleaned off while operating in a highly corrosive environment, eventually that neglect can lead to frame issues, as it can for every other brand. But those other brands aren't typically as reliable, so they get scraped sooner. I saw it regularly when I worked in a repair shop that worked on all brands.
 
Here's a '96 with 526k miles on my lift right now. I dunno if this proves much because things don't rust much in SW Colo (even when it's snowing the air is dry)View attachment 268653View attachment 268654

I bought mine from a guy in Wisconsin, who inherited it from his mother who was a realtor in Colorado. I found a business card from Durango the first time I detailed it.

I'm from Michigan where they use plenty of salt all winter, and winter is long. Every Fall I would coat the underside of our vehicles with Fluid Film. A couple of times a month I would spray our cars off on warm days, and then spray WD40 in the wheel-wells and kick panels. This process worked pretty well and kept new rust to a minimum.

Being in Virginia now, the winters aren't nearly as bad and neither is the salt usage. I have some mild surface rust that I want to touch up over the summer. Hopefully, I won't be replacing fuel injectors this summer...
 
I bought mine from a guy in Wisconsin, who inherited it from his mother who was a realtor in Colorado. I found a business card from Durango the first time I detailed it.

I'm from Michigan where they use plenty of salt all winter, and winter is long. Every Fall I would coat the underside of our vehicles with Fluid Film. A couple of times a month I would spray our cars off on warm days, and then spray WD40 in the wheel-wells and kick panels. This process worked pretty well and kept new rust to a minimum.

Being in Virginia now, the winters aren't nearly as bad and neither is the salt usage. I have some mild surface rust that I want to touch up over the summer. Hopefully, I won't be replacing fuel injectors this summer...
Interesting, I wonder if you got the scary airbox warning this one did? Warning! YoUR cAr haS ComPOoTerS!!
20250314_145721.webp
 
Interesting, I wonder if you got the scary airbox warning this one did? Warning! YoUR cAr haS ComPOoTerS!!View attachment 268668

Nope! Didn't have that, or the dreaded K&N sticker. Yours looks solid still, and congrats on the half million mileage; impressive! The Gen 3 4Runner is the first vehicle that I ever considered buying used at 200k miles. It's also the vehicle that got me i to liking Toyotas almost twenty years ago. High mileage is different for these than most other vehicles.
 
Im another for not using much reman anymore. I have had good luck with Advance auto starters, but their calipers rebuild units stick. I had one blow out the seal and leak everywhere while pushing the piston back when I suspected it was binding. They look beautiful. I suspect poor quality rubber parts swelling up. I get that they don't make a ton of money on rebuilding things. But why bother if it's not done right? It must be that 1/2 of the people that buy these parts just give up and eat the decision. Like with these calipers that were in 10 months. I just wanted to buy new at that point because the chances are I will be doing them again in... Follow me here. Take a guess. You guess correctly! 10 months. Is that cost effective for me a DYI guy? Or worse, You the guy trying to feed their children. Nope. Someone needs to say no. Say no to reman electric injectors. Even if they can get them apart, how good are the new seals and rebuild parts? Mechanical ones sure because as said they can get them apart. Area diesel does a great job in this realm.
 
And somehow all 8 factory injectors on my two old trucks are still perfect, one with 269k and the other 341k. But those old injectors which i think are delphi or bosch must be better than the new ones. I don't think the new ones would last that long anymore. Quality of everything has gone down for the most part.

It'd have to be bad luck if everything else is measuring ok. I doubt the computer is misreporting numbers.
I've never heard of needing injectors replaced on a gas engine.
 
Why do injectors fail? Electrical issues and mechanical issues.
Electrical issues. Opens and shorts. Why. Over current. undercurrent. Mosture. Heat. Have any of these?
Mechanical issues. Sticking. Stuck, Clogged, leaking
Poor fuel quality, Sitting lengths of time. Poor maintenance. Fuel line deteriation. Moisture. Internal seals
Does your vehicle have a replaceable fuel filter change it a regular intervals. Run fuel system cleaner once in a while in your fuel. Techron is a good one. You dont need to run premium fuel unless required my the MFG. Get your fuel from a reputable busy station. I only replaced fuel injectors in 3 in all my DIY years. 2 were GM "spider" types on the GM 4.3 Vortec as the seals blew out and the other was a subaru and I was guessing. It ran the same. I maintain 4 vehicles for myself and family. One time a injector connector was corroded and 2 mechanics replaced everything else but the connector! I did it myself with a junk yard one.
Yes things wear out eventually.
 
2000 4Runner is needing injectors for the 3rd time in a year...some bad luck with rebuilds?

As the title states, I'm headed towards my third set of injectors in the past year. Last May I threw a code for P0172 (bank too rich). I bought the 4Runner in 2018 with 201k miles on it, and the private seller had put a full set of new injectors in it. When I pulled them out last May, they looked like a cheap set, probably from a box store or Rock Auto; something India made. I can't blame them I guess since they were selling $5k vehicle, and a garage did the work so it was probably out of their control. It now has 251,xxx miles on it.

I use genuine TOYOTA parts from Ourisman Toyota in Richmond VA. In the past couple of years I have replaced:
- TPS
- IAC valve
- all new Denso coils
- Sumitomo plug wire set
- New NGK Plugs
- Cleaned the MAF sensor
- Magniflow cat-back exhaust
- new fuel pump, pick-up tube, sock filter, and sending unit
-the fuel filter back around 2019

Last May when I did the injectors I replaced the valve cover gaskets, PCV valve, fuel pressure regulator, O2 sensors, and the engine looked excellent inside given the mileage. It still doesn't burn oil and there are no signs of coolant issues. I used Motor West Performance injectors for the replacement. The repair went well, it ran great, my MPG went up a bit, and the code went away.

5 months later in October I got a P0172, again, and MWP sent me a new set with new intake plenum/manifold gaskets, and fuel rail banjo bolt seals. Again, the code went away and it ran great. I'm getting quite good at getting the injectors replaced quickly. I'm very careful inserting the new injectors using the provided lubricant, to not cut the o-rings, and also careful to not be sloppy with getting the lubricant where it doesn't belong.

The other day my Runner stumbled a bit at high idle after starting, and it surged a few times on me. I now had a good idea what was happening as this happened the other times as well. Yesterday my LTFT was is at -32.xx% and it actually died on my at my house, but it started right up. The LTFT was in this range the other times as well. If it does through a CEL it has only been for the P0172. Every time after the repair, my STFT and LTFT go back into the -10% to +10% range, and I monitor it for about 2 weeks until I feel confident its fixed. In that time it runs fine, and get 17.5-19.25 MPG.

Am I just having bad luck with "remanufactured" injectors? I know MWP has a good reputation, but I can't come to any other conclusion other than I keep getting injectors from them, and at least one fails after a few months. I know it may not be likely given their reputation, but it's also not impossible, and this is getting OLD. I read on the IH8 Mud forums that Denso fuel injectors are not truely rebuildable because they are a sealed unit. They can be cleaned, screens replaced, replace o-rings, and tested, but they can't replace the solenoids, coils, pintle, return springs, or valves. If this is true, this is a great point and piece of knowledge.

page 2, post #24
https://forum.ih8mud.com/threads/refurbished-fuel-injectors.1225257/page-2


The reason I believe that its a bad fuel injector, and at this point not another issue, is that new injectors always fix it with no lingering problems. I would think that if its related to the ECM, bad wiring, or bad Toyota fuel system replacement parts, the issue would persist immediately, even after new injectors. All the other data from the IAT sensor, MAF sensor, TPS sensor, Coolant Temp sensor, and 02 sensors are correct and with in a healthy range.

I would like some thoughts on this. MWP has a Million Mile/Lifetime warranty on their injectors for the 5VZFE, but I'm very tempted to just get a new set of genuine Toyota Denso injectors from Oursiman Toyota at $166/each, and hopefully be done with this. Yota Shop has Aisin injectors that are claimed to be new OEM (I know Aisin makes good stuff) for a much cheaper $89.37/each, but I'm wondering if I need to stop cheaping out on this, bite the bullet, and just go new Toyota injectors. If this happened again after doing so, I would be confident that there is another issue. I just don't know what that might be if a new set of injectors always solves the issue.

For fun and general interest, I've attached a few photos of what the heads look like once the covers removed; I was happy with what I saw. I'm liking Valvoline in our Yotas, and I'm currently running the Valvoline Restore and Protect.

View attachment 268439

View attachment 268440

View attachment 268441

View attachment 268442

View attachment 268443

View attachment 268444

View attachment 268445
I'm getting ready to send mone to the fuel injector rebuild company in Georgia, then be fone with it.
 
I've never heard of needing injectors replaced on a gas engine.
I've heard of it...such as this thread, but I have never replaced injectors...and I've got 382,000 miles on my BMW 540, and Tundra with 390,000 miles...both with the factory original fuel injectors... I've owned since new.
 
Last edited:
I'll give an update. So far its been a few months, and I have almost 3400 miles on the Toyota injectors and everything is still fine. I checked the fuel trims about once a week and everything is right where it should be. I'm still getting about 18.9 to 19.2 MPG, or about 280-300 miles per tank of gas before needing a fill up. In that same amount of miles or less, I had at least one Motor West Performance injector fail. I still say they their customer service is excellent and that they are a good option for people. They just didn't workout for me.
 
I'm getting ready to send mone to the fuel injector rebuild company in Georgia, then be fone with it.

Did you call them and ask them if the truly rebuild them, or do they refurbish them? My research found that an injector is sealed, and that the internals cannot be replaced. They can only be cleaned, the o-rings and screens replaced, followed by a flow test. I'd be curious if they can actually rebuild them and prove it. I'm not saying they can't since research online can only result in so much information, but I would be curious of what they say.
 
Did you call them and ask them if the truly rebuild them, or do they refurbish them? My research found that an injector is sealed, and that the internals cannot be replaced. They can only be cleaned, the o-rings and screens replaced, followed by a flow test. I'd be curious if they can actually rebuild them and prove it. I'm not saying they can't since research online can only result in so much information, but I would be curious of what they say.
There is nothing to replace beyond the o- ring. Maybe the spring? It’s just a needle valve, an electrical coil and a spring. I assume they get gummed up and an ultrasonic cleaning fixes that?

Having said that I am also in the camp that they should rarely fail. My 415,000 mile xterra is on original injectors. My Frontier has 225K - all original injectors.
 
There is nothing to replace beyond the o- ring. Maybe the spring? It’s just a needle valve, an electrical coil and a spring. I assume they get gummed up and an ultrasonic cleaning fixes that?

Having said that I am also in the camp that they should rarely fail. My 415,000 mile xterra is on original injectors. My Frontier has 225K - all original injectors.

You might be right and maybe I just had bad luck. In my case, new injectors fixed my issue immediately, every time. If it were bad wiring or a connector, I think it's logical to assume that the problem would persist even with another installed set of injectors. So far the brand new Toyota injectors are lasting the longest and the fuel trim numbers are still in a good range. I hope that continues.

Motor West was supposed to call me after checking the last set of injectors I returned to them. I would have been curious to hear what they found after test them, and it could help with the diagnosis.

If I go a year without issues, I'll feel good.
 
Back
Top Bottom