just wondering , after how many years / klm is it wise to do an injector clean? i know that these Nulon bottles help , but its better to remove and get them bench cleaned if poss. my local place will do them for $160 off the car. i dont know if that includes replacing the little o rings , etc.

You will get different answers! You choose which one you take heed of. lol

My answer: don't bother, unless you are chasing a misfire or rough idle not caused by bad plugs, leads or poor compression. Most cars knock up huge mileages without a clean with no problems.

I've used different brands of cleaners over the years and had them bench cleaned once - every time because it was 'recommended' ....noticed no difference after any of them so I'm with MadMax on this one. However, if you are actually experiencing injector related problems then it is a different matter. Some people say that premium fuel contains injector cleaners in it.....maybe it's hearsay.

If you read my injector cleaning thread, there are many members here who will disagree with you completely

No you say
I've used different brands of cleaners over the years and had them bench cleaned once - every time because it was 'recommended' ....noticed no difference after any of them so you have had many bottles of throttle in the bottle in the tank and noticed no difference, no wonder here as the tank additive is not going to do much other than clean out the tank and absorb any moisture. The bench clean, I assume Ultrasonic, if they were very dirty, you will get some improvement, if not, then at least you know they are done and should not be an issue in the future

For starters, from a professional point of view, once you understand how combustion, fuel varnish etc etc work, then you will think again very fast

$160 for injectors ultrasonically cleaned is quite good provided they are actually doing this.

Bottle in a tank is a waste of money unless being used to remove moisture as that is all it is good for

The onboard are good as they not only clean the injectors but also clean everything in the path from the tip of the injector back to the oxy sensor

Stating dont do it until you are chasing a misfire is like saying dont check your oil until you run out. For starters if you have then blocked an injector, the cost of a single injector is often more than the cost of the flush in the first place, and then there is the time spent chasing this mis fire, if you use preventitve maintenance then you will save money in the long run. If you just wait until gear breaks or fails, then you will spend a lot more in the long run

As for when to do this, generally I would say every 48 months if you do a lot of city driving or 50k if you do a lot of open road driving. Lets face it, the cost even at retail for the onboard clean is not that much and the money and inconvenience it can save you in the long run is even more

The OP asked "just wondering , after how many years / klm is it wise to do an injector clean?"
The experience I posted asks why spend $160 when you don't need to. When I tried treatments and bench cleaning it was because simply because it was "the done thing". I took notice of what I read on various forums and word of mouth - figured it might be cheap insurance to clean the injectors etc but never noticed any difference - but then I never had problems before or after, so naturally I could be excused to assume that my outlays were unnecessary because they appeared to achieve no change.
Others on this forum will have had different experiences...which is what a forum is about. :)

I warned the OP that he would get a lot of different answers! lol

It's up to him to decide what he is most comfortable with.

I agree that putting stuff in the tank is a waste of money.

I wonder what the official service procedure from Mitsu says about injector cleaning?
Is it in the service manual at all?
What do different dealers recommend? And do they all AGREE on the same time/distance recommendation? lol

The OP asked "just wondering , after how many years / klm is it wise to do an injector clean?"
The experience I posted asks why spend $160 when you don't need to. When I tried treatments and bench cleaning it was because simply because it was "the done thing". I took notice of what I read on various forums and word of mouth - figured it might be cheap insurance to clean the injectors etc but never noticed any difference - but then I never had problems before or after, so naturally I could be excused to assume that my outlays were unnecessary because they appeared to achieve no change.
Others on this forum will have had different experiences...which is what a forum is about. :)

That's a very interesting theory, based on this why bother servicing a car at all? If you keep your car serviced regularly, you will have no issues, meaning it was unnecessary? I mean your car was working fine before the service right?

I had my injectors cleaned at 130,000kms, they seemed fine up until then, but I immediately dropped fuel consumption by half a litre per 100 and the car ran smoother. I've spoken to others who have had the same affect, and some who didn't notice any difference.

I know there are "gimmicks" out there, but I do believe that this is necessary and not one of them, i'd probably do it every 50-100k kms personally.

I immediately dropped fuel consumption by half a litre per 100 and the car ran smoother.
+1 for that, i had madmagna do mine a few months ago, actually the cheapest and most usefull thing ive done to my car :) (and i thought it was fine before that!)

Following some of the above advise, I may just decide to stop brushing my teeth, and only go to the dentist when I have a tooth ache. <sarcasm>
Anybody heard of the term "preventative maintenance"?

I had Madmagna do the injectors on my TL. I've had it for 2 months, and the car had 114,000 on the clock plus a relatively unknown history prior to the previous owner.

The injector clean made a very noticeable difference. The biggest change is when you first apply the accelerator - rather than a lag the car just jumps into life. It has amazing performance off the line now - much better than my XR6 turbo (until the turbo kicks in anyway!).

As of this point I'll be getting Madmagna to do an injector clean every year at least.

$160 for injectors ultrasonically cleaned is quite good provided they are actually doing this.

Bottle in a tank is a waste of money unless being used to remove moisture as that is all it is good for

The onboard are good as they not only clean the injectors but also clean everything in the path from the tip of the injector back to the oxy sensor

As for when to do this, generally I would say every 48 months if you do a lot of city driving or 50k if you do a lot of open road driving. Lets face it, the cost even at retail for the onboard clean is not that much and the money and inconvenience it can save you in the long run is even more

thanks mal
i'm pretty sure its an ultrasonic clean. its a bench mounted unit with graduated vertical tubes , presumably for measureing how much comes out in a given time.

i'll get them done while i'm doing the next major service.

I guess with the comments above agaon Max your theory is not really standing up. GTVi i like you example and it really is the same. Why wait till it breaks. If start to get issues then the damage is done, clean it before and ir will last

The RACQ fact sheet on fuel injector cleaning states in part "Actual problems arising from such deposits occur fairly infrequently and based on that alone it would be difficult to justify frequent servicing. Ultimately however it is up to you, as the vehicle's owner, to choose when such servicing is performed."
You pays your money and you takes your choice.