Fuel Injectors $$$

Consider getting yours rebuilt. @ChapmanF may be holding a set of already-rebuilt ones that could work for you in a swap exchange.

 

The ones @ChapmanF has were rebuilt by a professional. For a while, guys on the forum had a swap process, where a set of injectors were sent for rebuild. Anyone who needed them just needed to ask, and they would be sent to them. Then that person would install them and send his old ones to the same rebuilder to have them refurbed and sent to Chap. and so on and so on and so on. This way, there was always a set of prime injectors ready for anyone who needed them.

 

There's a shop right here in my town that does it A big outfit like diesel injection service or something nonsense like that and I had them redo a set of mine recalibrate them and whatever it is they do they handed them back to me with a clean bill of health and they even showed me basically what they look like before they start and what happens and what's going on after I even got to go on somewhat of a shop tour The place is pretty big. And the car that I put the injectors on did not make any difference in how the car ran and I haven't seen or run any tanks through yet to see about gas mileage I wasn't having gas mileage problems and dilution problems I was having running problems so I figured it right at 300,000 mi it certainly is not going to hurt anything.

 

We did three cycles of that injector-rebuild plan. I still have the last of the sets that got rebuilt. They've been sitting here several years now, so I would have to test-power them to make sure they still click; the preserving oil Rich puts on them after rebuilding could have gone a little thick by now. As long as they do click, it'll be washed out by the fuel once they're installed.

A real benefit of doing them that way is Rich would test them on the bench and include a report of the before/after test results with the rebuilt injectors. The 'after' result was always great. Of the three sets we did, the 'before' results were also great, two of the three times. The other set had clearly bad 'before' results, and lo and behold, that was the car whose rough-running problems were fixed by replacing the injectors.

The other two cars were clearly suffering from something other than injector problems—but by having the test results, now we knew that.

One useful lesson was that, while it is possible for the Toyota injectors to go bad, it's by no mean inevitable—they can also have a lot of years and miles on them and be just fine. The bench tests are good for settling that question if there is doubt about a particular set.

 

I just figured with the fuel that we're being dealt now and everything else that can get in the tank at 300k a decent set of rebuilt injectors or a set of new makes reasonable sense whether it changes anything running or not well that's all good and fun I wasn't really expecting anything like that but just knowing that they're clean and operating effectively is good enough for me.

 

What are your total fuel trims in ECM data (at hot idle, cruise, and moderate acceleration)?

If fuel injectors are leaking (or bad spray pattern) enough to cause dilution of the crankcase, then I might expect to see it in fuel trims.

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If you are talking like for like, that is, comparing new with new and not new with refurbed, then there is no real mystery. Counterfeit car parts are great money earners for counterfeiters and are all over the internet, even on (especially on) places like Amazon and eBay. Any part that claims to be OEM but is ½ to a 1/10th of the price of an OEM is sure to be counterfeit.

If you want the best price for OEM, go to a competitive OEM online parts store that regularly offers 20% - 30% on the OEM MSRP (like Olathe Toyota KS). You get genuine OEM parts for a good price.

 

Used to be there was a lot more involved manufacturing a fuel injector remember they used to be metal alloys of metal pressed together all of that manufacturing stuff. Now they're all plastic and throw away they make a million throw out $100,000 whatever It's a numbers game for everybody now even Toyota has fallen to it planned obsolescence and all of it it's just for likes and numbers that's it doesn't matter what really goes on in the real world at all . It's about likes clicks the end.

 

I hadn't understood the line of your questioning before.

The answer is that you probably have not seen how utterly horrible a counterfeit part can be, especially in a precision application like a fuel injector.

Now that I've re-read this thread, you're thinking about replacing the fuel injectors in your car because of the idea that $120 and an afternoon spent swapping injectors might get you back a little power and economy that time seems to have robbed.

Well.. I can say that a brand new set of the real Toyota ones has a slight chance of doing that... but it's pretty slight.

The counterfeit ones from the internet have zero chance of doing this. Save your money.

If you still feel like doing it the hard way but want to hedge your bets, maybe get an extra set of injector seals. That way if you crack your old ones taking them out, you'll have fresh ones to reinstall after you give up on the counterfeits a day or two later.

 

They also have a nonzero chance of being DOA, working poorly, or failing quickly.

 

It's a lot of money for a lot of people, which is why a few of us have encouraged doing some more diagnostics rather than just installing some parts and hoping for the best.

I only turned wrenches for a few years to put myself through school, but like you I got out of it right before computer-aided diagnostics took off.

I encourage you to make the leap. I've been using a laptop to help diagnose the family cars for the last few years, and just made the jump to a smartphone-based system. (Autel 2500E) I do a little of my own mechanical work, and it really helps to have raw, real diagnostic info to help decide which problems I want to tackle vs. what I hire out.

So start with what you've got, what you're already comfortable with- phone, tablet or laptop. There are ways to use most any of them to connect to your car and make smarter diagnoses.

 

The thing is with a scantool, you can see how hard the ECM has to compensate (or not) in order to keep fuel mixture on target.

Any significant problem with the injectors has to affect fuel mixture and the combustion process. That would show as richer or leaner than the target value, and fuel trims would have to adjust away from 0.

I have seen repair cases where Gen2 injectors were restricted and had poor spray patterns - fuel trims made large positive (over +20%) corrections. Leaking injectors cause negative corrections (-5%, -10%, -20%, etc)

My 2006 has 220k on it and fuel trims are 0 +/- 2%, which is pretty much how it left the factory.

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The fuel trims that mr_guy_mann referenced in post #16 bear heavily on your injector theory. I think that should be the first thing you look for.

From a strictly diagnostic point of view, if you find the long-term fuel trims in your car to be substantially negative, that would indicate leaking injectors that are forcing your mixture over-rich some of the time, resulting in oil dilution.

If you find those trims to be close to zero (or positive), then your injectors aren't leaking. Look elsewhere for your troubles.

On to it.

I'm not familiar with the software you've got, but we have a few things working for us here.

The most basic scan tools out there exist to get information from electronic fuel injection and electronic ignition systems, because those were the first "computerized" things on car engines. So essentially any tool you have can gain access to that basic level of info.

In a nutshell, the 'fuel trim' is the numerical result of the ECU giving the engine a certain amount of fuel, then monitoring the oxygen sensor in the exhaust manifold to determine whether or not the air/fuel ratio was correct just a moment ago. If the sensor says the mix was lean, the ECU starts a positive short term fuel trim in response. If the mix was rich, the ECU pulls a negative short term fuel trim. The next time the injectors cycle, the fuel load will be trimmed positive or negative.

That cycle repeats itself in real-time.

On top of that, another process in the ECU takes a look at the recent history of short-term fuel trims. If it sees a continuous trend of positive trims, it will make a positive long-term trim. The trim applied is the sum of short and long term values. (same goes for negative trimming)

Watching the difference between short and long term trims can help you make a distinction between spurious events and persistent conditions.

As mr_guy_mann relates in post #16, a car with leaking injectors is generally going to show a substantial negative long-term fuel trim.

This means that the computer has realized that it is putting in less fuel than it thinks is necessary. It doesn't know why, it doesn't care; it's just keeping score. But if the injector leak + a certain bonus amount of fuel = exactly the right amount, it will run well and adjust on the fly. The problem is when you close the throttle- the system can only cut so much fuel. If the leakage alone = too rich, you'll get potential for oil dilution.

Most scan tools and software packages abbreviate these data lines as 'STFT' and 'LTFT' for Short and Long -term.

Often you can browse your way straight to those readouts, since it's some of the most standard stuff to check- they don't usually hide it in these scan tools.

Hope this helps, and don't hesitate to ask.