When to Clean or Replace fuel injectors

[2001LC]

Please post your experiences and thoughts on the subject.

I’ve been considering cleaning or even replacing all 8 fuel injectors, is this wasting time and money. I understand keeping fuel injector clean by adding a can of additive to the gas tank, now & then, is a good practice. This keeps them operating at peak performance, but for how long. When should we do more and what should be done. Do they weaken over time reducing performance or preform at peak until failure. I’ve read they’re good for 1 billion cycles, which I've read is ~350K miles. How about seals, should they be included in our PM.

I’ve rebuilt my share of carburetors, but have never even pulled an injector. Realizing I know very little about them except they work better than carbs and are certainly less maintenance. So I've started this thread and post a few links to help answer these question.

Edited 8/24/17:
We've two new issues found with our fuel systems, see post #20. One of which is: Apparently our Fuel Pressure Regulator (FPR) needle is being rusted by bad gas (Corn gas additive, cheap gas, bad filling station holding tanks leaks or rust) or just lack of daily driving. Second, Denso no longer makes our injectors.

Also see leaky fuel injectors in post #20. Robbie in Boulder CO had a come-back for "hard start". They had fuel injector serviced, then ended up pulling again and having FIS retest. After finding leaky (leaks while parked) fuel injectors, they replaced and all was good.

Edited 3-19-16.
I've recently pick-up an under maintained 01 LX470 214K on clock, that I'm going through everything (baseline). Pulled intake manifold and broke it down too clean, replace all gaskets & seals and have fuel injectors cleaned, tested & rebuilt.

I found Fuel Injector Specialists (FIS) in the Denver area after searching & asking around, to service my injectors. I read through FIS web page then spoke with Chuck the owner/operator, I liked what he had to say. So I dropped them off and 48 hour later I had my report, and completely rebuild set of fuel injectors.

I also received a full set of before & after pictures (hard copy) along with old parts. Below is the report I received with four after rebuild pictures:

Here is the report:
"Refer to the 4 attached pictures, all of which are "after" rebuild.

Low pressure picture (the fuel streams are more distinct) shows problems with injector #2 -- the left stream of this injector is weak, not nearly the flow of the right stream. As it is, the TOTAL flow volume of this injector is only down a bit (refer to the 15 seconds static volume picture). Here is where we differ from ANY injector service currently in business-- ALL OF OUR COMPETITION, including the big boys like GB in San Diego and Autolite in Canada, WILL PASS OR FAIL AN INJECTOR SOLELY BASED ON VOLUME. Pattern is not an issue, because their minimum wage help is not trained to recognize pattern differences and issues.

We are convinced that the absolute key to smooth running and high gas mileage, and a great warm idle, is PATTERN. Your number two injector has an unbalanced fuel stream.

Your #3 injector ALSO has an unbalanced fuel stream, only in this case the LH fuel stream is "sharp", and never atomizes properly, as shown in the "high Pressure" pattern picture (high pressure = fuzzier fuel streams). Again, this is why we do "high and low", hot and cold testing.

We recommend replacing #2 and #3. All have been hand etched with the appropriate numbers.

The resistance values on all are within spec, and there is no bleed down hot or cold.

Thanks.

Chuck

Also, we are the ONLY company which will show you a 25/75 duty cycle pic. We do a lot of work for "Adventure Offroad" in Boulder; they are high end Landcruiser specialists ($75k restorations, etc.) The last set of injectors from them tested perfectly on static (injector held open) volume. But, 25/75 duty pic showed a 30% difference!! Injector was poorly manufactured NEW, excessive needle lift, and the unaware owner(s) has had injector issues forever."
End of report.

Special for mud members:
Chuck at Fuel Injector Specialists - Home - Wheat Ridge, CO (FIS) has agreed to give mud members a discount. Mention your from MUD to Chuck, he’ll take special care of mud members for a limited time.

Here's a video on fuel tank additives that list the top ten. 44K took #1 spot.
10 Best Fuel System Cleaners 2017

End of edit 3-19-16.

Using a Multimeter to Test Fuel Injector Using Resistance (Ohms)

Should we have them professionally cleaned on engine? (added benefit, gives fuel pressure report)

Should they be professionally cleaned & tested, off engine? (added benefit, flow & spray pattern report)

 

[arcteryx]

I rebuilt my injectors on my 1FZ last year, mainly because 1 went bad at 195K. So while I was in there, I decided to do all of them while everything was open. I am not sure what exactly caused the injector to go bad but the gasket/seal started to go, so that probably did it.

When I was getting them rebuilt at the shop, I asked what was going to be done and if they really needed to be a maintenance task. They replied that there is not much you can do to gasser ones, basically clean them and ensure the flow pattern is correct. I paid $30/$31 per injector FWIW. And other than it running better with the fixed injector, I did not get any better MPG. All that said, I would not do anything to them unless one starts to go bad, and then rebuild/replace the 4 on the bank. They are not like diesel injectors that require much more work and cost.

 

[Trunk Monkey]

If you're looking to spend money unnecessarily - sure! Clean them if you have a problem with them, but otherwise you're once again just looking for problems that don't exist.

 

[Julian Stead]

I would say a waste of money unless you think they are causing any issues. I have never changed them for preventative maintanence, only if they turn faulty, and that is farely rare. Just use good fuel and add a fuel cleaner once a year.

The engine management system does a good job at adjusting the injection duration to compensate for any imperfections in combustion.

 

[Nottajeep]

the little rubber gaskets around the injectors go bad over time and start to shrink. (these can be ordered for very little money)
When I was replacing my starter, I broke one injector sitting the manifold back on.
Mine look to be very fragile after 200k and 16 yrs.

 

[TeCKis300]

Not an issue and a waste of money IMO. With modern fuel injection and closed loop fueling, the car will run very optimally over the lifetime of the engine. I don't believe the injector is the limiting engine component either.

In the unlikely event there is an issue, OBD-II will surely identify the problem and let you know via a check engine light.

 

[2001LC]

I rebuilt my injectors on my 1FZ last year, mainly because 1 went bad at 195K. So while I was in there, I decided to do all of them while everything was open. I am not sure what exactly caused the injector to go bad but the gasket/seal started to go, so that probably did it.

When I was getting them rebuilt at the shop, I asked what was going to be done and if they really needed to be a maintenance task. They replied that there is not much you can do to gasser ones, basically clean them and ensure the flow pattern is correct. I paid $30/$31 per injector FWIW. And other than it running better with the fixed injector, I did not get any better MPG. All that said, I would not do anything to them unless one starts to go bad, and then rebuild/replace the 4 on the bank. They are not like diesel injectors that require much more work and cost.

Great I was hoping for some personal experience and actionable advise too, thank you.

How do you recommend cleaning i.e. Cleaning agent added to gas tank, Cleaning with kit attached to fuel rails, Removing and sending out to a shop that specialize or some combination?

I saw one TX shop offer $18 per plus shipping cost for cleaning & rebuild, sound reasonable.

If you're looking to spend money unnecessarily - sure! Clean them if you have a problem with them, but otherwise you're once again just looking for problems that don't exist.

Hopefully thread would help those with less knowledge on the subject, myself included, find actionable Fuel Injector info fast & easily, from real-world experience and experts such as yourself. Too workout issues, long-term budget & scheduling.

I would say a waste of money unless you think they are causing any issues. I have never changed them for preventative maintanence, only if they turn faulty, and that is farely rare. Just use good fuel and add a fuel cleaner once a year.

The engine management system does a good job at adjusting the injection duration to compensate for any imperfections in combustion.

Thank you, good advise & info.
Which cleaner do you like?

the little rubber gaskets around the injectors go bad over time and start to shrink. (these can be ordered for very little money)
When I was replacing my starter, I broke one injector sitting the manifold back on.
Mine look to be very fragile after 200k and 16 yrs.

Thanks for the heads up; I'll used caution with or working in area of injectors. Sounds like a seal kit would be a good & inexpensive idea too.

By fragile I assume you mean plastic housing becoming brittle (possible from heat & age)?

Not an issue and a waste of money IMO. With modern fuel injection and closed loop fueling, the car will run very optimally over the lifetime of the engine. I don't believe the injector is the limiting engine component either.

In the unlikely event there is an issue, OBD-II will surely identify the problem and let you know via a check engine light.

Good points, but is optimally at peak?

 

[Julian Stead]

I use Forte gas treatment, Forte make very good products, not sure if they sell it in the U.S though.

 

[arcteryx]

I don't think cleaning these are a DIY. If you are going to do it, I would send it to a shop so they can flow test them. I used Austin Fuel Injection. $18 is good if they are reputable. I know there are some other places online that do them for around $20, I just used a local shop to for convenience and speed.

 

[2001LC]

I use Forte gas treatment, Forte make very good products, not sure if they sell it in the U.S though.

I've never seen in stores, but until today hadn't looked. Doing online search I come up with dot UK web addresses, so I guess not a US product.

I don't think cleaning these are a DIY. If you are going to do it, I would send it to a shop so they can flow test them. I used Austin Fuel Injection. $18 is good if they are reputable. I know there are some other places online that do them for around $20, I just used a local shop to for convenience and speed.

Good point as they shop can give report on flow and spray pattern as well. So I'll plan on sending out the injectors when I pull them, but that's not for some time yet.

I'm planning on doing a minor top end job, completing by ~180K miles. This will start with compression test this summer. Then a complete T-Belt & WP job, starter R&R, valve gap inspection & cover gasket, heater T's, PCV and any hoses needed.

I generally use BG 44k in the gas tank and clean T-Body every year or two. I have just read BG recommends using BG fuel injector cleaner with professional tool that hooks to fuel rail(s) followed by 44k in tank.
If I understand correctly; our engines are non EGR and use indirect fuel injector system. So are not subject to exhaust gas recirculating gunk and as much heat on cool down as direct in-head fuel injectors. Have I got this right?

Is this professional shop tool connecting to rails a good idea or a waste of money?

Do driving habits make a difference in best practice here?

 

[2001LC]

I've edited OP to reflex thread posting and findings, hope everyone finds informative & helpfully.

It seem best practice is to keep clean & replace seals as needed. Not sure if we have much data on when seals may need replacing based on age, millage or combination of both. Other than pulling and looking at them. I suppose we may as well replace whenever fuel injector pulled.

 

[oakback]

In the unlikely event there is an issue, OBD-II will surely identify the problem and let you know via a check engine light.

For anyone wondering, this shows up as a misfire with cylinder # (at least it did on mine). To determine if it's the coil or injector, put a long socket extension or screwdriver against the injector, and the other end against your ear, and see if you can hear it ticking when the engine is running. Compare the sound to other injectors if you're not sure. Easy and cheap way to save yourself some time and potentially money.

 

[2001LC]

I'm going to have my 01 LC fuel injectors clean, test & rebuilt after what I've now learned. Read on:

I've pick up an under maintained 01 LX470 w/214k on clock, that I'm going through everything (baseline). Pulled intake manifold (Thanks to Mickey & Minnie Engine wash) and broke it down too clean, replace all gaskets & seals and have fuel injectors cleaned, rebuilt and tested.

I found Fuel Injector Specialists - Home - Wheat Ridge, CO (FIS) in the Denver area, after searching & asking around. I read through FIS web page then spoke with Chuck the owner/operator, I liked what he had to say. So I dropped them off, and 48 hour later I had my report and completely rebuild set of fuel injectors (Cleaned, tested, new filter and new seals included).

I also received a full set of before & after pictures (hard copy) along with old parts.
Below is the report I received with just four of the many pictures:

The report:
"Refer to the 4 attached pictures, all of which are "after" rebuild.

Low pressure picture (the fuel streams are more distinct) shows problems with injector #2 -- the left stream of this injector is weak, not nearly the flow of the right stream. As it is, the TOTAL flow volume of this injector is only down a bit (refer to the 15 seconds static volume picture). Here is where we differ from ANY injector service currently in business-- ALL OF OUR COMPETITION, including the big boys like GB in San Diego and Autolite in Canada, WILL PASS OR FAIL AN INJECTOR SOLELY BASED ON VOLUME. Pattern is not an issue, because their minimum wage help is not trained to recognize pattern differences and issues.

We are convinced that the absolute key to smooth running and high gas mileage, and a great warm idle, is PATTERN. Your number two injector has an unbalanced fuel stream.

Your #3 injector ALSO has an unbalanced fuel stream, only in this case the LH fuel stream is "sharp", and never atomizes properly, as shown in the "high Pressure" pattern picture (high pressure = fuzzier fuel streams). Again, this is why we do "high and low", hot and cold testing.

We recommend replacing #2 and #3. All have been hand etched with the appropriate numbers.

The resistance values on all are within spec, and there is no bleed down hot or cold.

Thanks.

Chuck

Also, we are the ONLY company which will show you a 25/75 duty cycle pic. We do a lot of work for "Adventure Offroad" in Boulder; they are high end Landcruiser specialists ($75k restorations, etc.) The last set of injectors from them tested perfectly on static (injector held open) volume. But, 25/75 duty pic showed a 30% difference!! Injector was poorly manufactured NEW, excessive needle lift, and the unaware owner(s) has had injector issues forever."

Special deal for mud:
Chuck at Fuel Injector Specialists - Home - Wheat Ridge, CO (FIS) has agreed to give mud members a discount. Mention your from MUD, he’ll take special care of mud members for a limited time.

 

[camino70]

Wow! Great info, thanks!

 

[Mike6158]

The next to last post looks like the first post?

 

[camino70]

The next to last post looks like the first post?

I think he edited the first post with the good stuff when he got his results and pictures later.

 

[PabloCruise]

So was this money well spent? How much was it to get 8 injectors serviced?

 

[2001LC]

I think it's worth it. Read his web page Fuel Injector Specialists - Home - Wheat Ridge, CO see what you think. He charges $20 each, but only charges for one's that test good. In my case he found two with poor spray pattern, for which he didn't charge anything. He's negotiable and may still give discount if you tell your from MUD.

 

[PabloCruise]

I think it's worth it. Read his web page Fuel Injector Specialists - Home - Wheat Ridge, CO see what you think. He charges $20 each, but only charges for one's that test good. In my case he found two with poor spray pattern, for which he didn't charge anything. He's negotiable and may still give discount if you tell your from MUD.

Sweet, thanks. I have a non-Cruiser project going on right now, but the injectors have a few miles on them, prob ~250k. I left them a message.

 

[2001LC]

I recently used FIS injector service again, great service which "word" is getting around on them (they are getting very busy).

It seems we've a new issue to watch for. Something @spressomon alert me to, after he used and spoke with Chuck at FIS.

Apparently our Fuel Pressure Regulator (FPR) needle is being rusted by bad gas (Corn gas additive, cheap gas, bad filling station holding tanks leaks or rust) or just lack of daily driving. Gasoline attracts moisture that settles in bottom of gas tank, where fuel pump picks up first. In aircraft we do a per-flight inspection which includes draining off water from fuel tanks, be nice if we could do that in the 100 sereis.

We can use good gas and put additive in gas tank to compensate/protect for moisture. Chuck recommends products like Chevron Techron for fuel injectors or Stabil when sitting for gas tank, just to name a few produce on the market. @abuck told me he uses Mystery Oil (ATF) in his gas tank for fuel injectors. This stuff all help protect our fuel systems.

One clue to a bad FPR is MPG that is erratic while driving habits are constant. It seem temperature effect how well FPR does or doesn't work, when micro spec of rust are on needle. Chuck said around 98 deg F is where most show up bad, but that varies. This is near impossible to test for on our engine by FSM method. Chuck said; he starts see issue around 100K miles and by 150K miles FPR need replacing.

Anyway, I used FIS to service Snowy's fuel injector and he found 5 leaking, in test FSM procedure would not likely have found. He's changed his testing for this after Robbie in Boulder CO had a come back for "hard start". They had fuel injector serviced, then ended up pulling again and having FIS retest. After finding leaky (leaks while parked) fuel injectors, they replaced and all was good. On Snowy FIS recommend all 8 be replaced after finding the 5 leaking, I was already replacing FPR.

We used aftermarket fuel injectors that chuck recommend from Standard Auto at $35 ea plus $5 to have FIS service. Chuck tested and cleaned the brand-new Standard's fuel injectors for me. He's found they come dirty from manufacture (bad), after servicing they work perfect.

Apparently Denso has stop making fuel injectors for 2UZ-fe and sold the mold to Standard Automotive. This aftermarket injectors' look just like Denso, they even say Denso on them and are made in America. Snowy is running like new now... SO SWEET.

To be fair, I did do much more to intake and ignition side of engine then just new FPR and fuel injectors. See Snowy in my signature to see all that was done to engine. It runs like new

Before new fuel injectors service by FIS:

After servicing (cleaning):