lifespan of diesel injectors?

Submitted: Tuesday, Feb 23, 2016 at 20:27
ThreadID: 131673 Views:11185 Replies:12 FollowUps:6
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Does anyone have an opinion on this - ive spoken to some who believe that diesel injectors are past their prime after 100k and should be replaced. Others not so much.
Has anyone done a pre-emptive replacement and found better performance they had forgotten existed?
My RA Rodeo has done the Lap twice with a van now, and wondering if its time even though
it seems to run ok.
Yes I know - if it aint broke don't fix it.
But there is another school of thought.
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Reply By: Member - Stephen L (Clare SA) - Tuesday, Feb 23, 2016 at 20:35

Tuesday, Feb 23, 2016 at 20:35
Hi Paul

My brother in law has his work horse, 100 Series Toyota with 475,000 on the clock. Everything is still original except brake pads, tyres and shockers.He services it every 10,000 km replacing oil and filters and being a farm vehicle, has had a hard life.

We were out at tea on Saturday nigh and that very question came up, and Pete said they were still the original injectors.


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AnswerID: 596559

Reply By: 9900Eagle - Tuesday, Feb 23, 2016 at 20:51

Tuesday, Feb 23, 2016 at 20:51
if your fuel consumption is still good, it is not starting to blow black smoke or you get the occasional knock from a dribbling injector, I would just leave them be. At some stage down the track they will start to go outside their wear limits, then replace them when one of the above shows it's head.
AnswerID: 596561

Reply By: Idler Chris - Tuesday, Feb 23, 2016 at 21:12

Tuesday, Feb 23, 2016 at 21:12
What wears injectors is the quantity and quality of fuel passing through them. If you do 100,000 k's at an average speed of say 90 kph you will pass a lot more fuel through the injectors than if you do the same 100,000 k's at say an average speed of 50 kph. The quality of the fuel is also important and you have no idea of the quality at any given servo. Most people install a second aftermarket fuel filter, and some a water trap as well. This I suspect, goes along way in preserving injectors.
There are too many uncontrollable factors to say how long injectors should last. All you can really do is keep a eye on your fuel consumption and black smoke. If fuel consumption starts to rise and/or you are getting more black smoke, then these are the usual signs of injectors in need of service or replacement.
I am not a mechanic or any sort of expect on these matters. This is just my experience over many years. A diesel mechanic may know more.
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AnswerID: 596563

Reply By: Rangiephil - Tuesday, Feb 23, 2016 at 21:33

Tuesday, Feb 23, 2016 at 21:33
I would think that the posters are referring to old technology engines with a pump.

Even my2002 Discovery 2 has ECU compensation for injector variations by measuring the acceleration of the crank after each injector firing using the crank position sensor.

I am sure common rail setups would also have this capacity.

You can read injector variation using a scan tool, and this will tell you the % variation of each injector. My D2 with 175KK has only about 2% variation.

Although the OP may have been referring to early Prado injectors which had a particular quality control problem that caused them to fail early, hence all the ads for rebuilt injectors.

So if you want to see how the injectors are do a scan.

Regards Philip A

AnswerID: 596567

Follow Up By: Dion - Wednesday, Feb 24, 2016 at 23:42

Wednesday, Feb 24, 2016 at 23:42
The OP specifically said a RA Rodeo.
FollowupID: 865521

Reply By: Michael H9 - Tuesday, Feb 23, 2016 at 22:57

Tuesday, Feb 23, 2016 at 22:57
I've got 2 CRD's both in the mid 200's and still on their original injectors.
AnswerID: 596573

Reply By: Nutta - Tuesday, Feb 23, 2016 at 23:19

Tuesday, Feb 23, 2016 at 23:19
My Gu 3.0l done 280k no problems, never blew any type of smoke, or blew up!
AnswerID: 596575

Follow Up By: Member - Outback Gazz - Wednesday, Feb 24, 2016 at 07:12

Wednesday, Feb 24, 2016 at 07:12

Purchased a new GQ Patrol in December 1988 and when it reached 200,000 k's somebody told me I should have the injectors replaced - which I did. Also fitted a secondary fuel filter. Sold the traytop in 2004 with 650,000 k's on with those same injectors. Spoke last year to the bloke who bought it and he said he put a new set of injectors in at 700,000 and it now has just over 900,000 k's on it and still going strong - best vehicle he ever owned he said !

Not sure the new common rails will achieve kilometres like this.


FollowupID: 865465

Follow Up By: Michael H9 - Wednesday, Feb 24, 2016 at 07:15

Wednesday, Feb 24, 2016 at 07:15
Although there are many crd taxis and courier vans in Europe with upwards of a million kilometres on them.
FollowupID: 865466

Follow Up By: Member - Outback Gazz - Wednesday, Feb 24, 2016 at 07:31

Wednesday, Feb 24, 2016 at 07:31
That's good to hear Michael - I would be happy just to get 500,000 out of my common rail - 3.5 years old now with 120,000 k's and is performing extremely well. Time will tell.


FollowupID: 865467

Reply By: Member - Trouper (NSW) - Wednesday, Feb 24, 2016 at 12:57

Wednesday, Feb 24, 2016 at 12:57
I own a 78 Series Troopy 2000 model. At about 248000 klicks I did notice, or thought i noticed a drop in performance (assuming the 1HZ ever had any). As the Ks increased over the next 6-8 months I definitely noticed a rise in fuel consumption from 12.5Lt per 100ks to 14Lt which was a measurable thing as apposed to a slight power loss short of putting it on a dyno. Anyway I finally sent it away at 253000ks to South Coast Diesel in Nowra (NSW) and had the injectors replaced and the valves adjusted, Cost was $1250 so now my fuel consumption is back to 12.5 and my 'power' has returned.

all good, money well spent, but as others have said wait until you notice any changes in performance or fuel increase...............................Jeff
AnswerID: 596595

Follow Up By: Member - Trouper (NSW) - Thursday, Feb 25, 2016 at 15:53

Thursday, Feb 25, 2016 at 15:53
8 of the valve clearances were out of spec and that was included in the cost. I thought I might have a go at the valves myself but after reading all about the procedure I decided to spend the money as I dont think my stomach would have appreciated leaning over the engine bay for hours, I'm a bit past that.
FollowupID: 865555

Reply By: riverman - Wednesday, Feb 24, 2016 at 16:09

Wednesday, Feb 24, 2016 at 16:09
just had injectors replaced last week in my 1hz 105 series at 330,000 ks just to give the old girl a treat ($680 all up) . No notable change in performance or fuel usage.
AnswerID: 596601

Reply By: Member - Terry W4 - Wednesday, Feb 24, 2016 at 17:36

Wednesday, Feb 24, 2016 at 17:36
Surprised no one has mentioned the need to check the injector values which is a very important measure of wear and tear.

In the Prado it is recommended by most owners that the readings should be no more that +3.0 and usually only last 125,000kms. Also the seats can be a problem in the Prado.

Get them checked every 10,000km. Most 120 Prados start to get out of spec after 120,000km. I checked mine and replaced at 125,000 before they were out but I was blowing white smoke on start up. Had checked at 150,000 service all OK. Missed doing at 160,000 but will do shortly with 170,000.

Ignore at your peril. Many Prado engines have 'popped' because this aspect ignored.

AnswerID: 596606

Follow Up By: Rangiephil - Wednesday, Feb 24, 2016 at 21:17

Wednesday, Feb 24, 2016 at 21:17
Funny I thought I did.
FollowupID: 865515

Reply By: Roachie Silverado - Wednesday, Feb 24, 2016 at 18:38

Wednesday, Feb 24, 2016 at 18:38
I drive for a courier company/Aussie Post contractor and they have a small fleet of Toyota Hiace vans. The one I drive has got 610,000 on the clock and was recently playing up. The mechanics thought it was the injectors, so replaced them, but it was worse than before.

Long story short.....the intake gallery was restricted down to about 10mm diameter due to the crud deposited via that wonderful invention...the EGR valve!!! The injectors were probably okay.

Other vans in the fleet that I also drive occasionally have done over (in the case of 2) or close to (another van) 1,000,000 klm and are still on the same injectors.

My own vehicle is a 2012 Silverado 6.6 Duramax. Being fearful of what the cost of injectors and/or injector pump might be, I was anxious to preserve both.

I now use Chemtech additive every time I fill up and more importantly I've fitted a FASS fuel lift pump/water separator and filtration system. The youtube clip shows how the device also removes minute air bubbles from the diesel.....this is apparently another long term killer of I fitted it just to be sure.

AnswerID: 596610

Reply By: Paul E6 - Wednesday, Feb 24, 2016 at 20:02

Wednesday, Feb 24, 2016 at 20:02
thanks for the replys fellows, very succinct.
AnswerID: 596615

Reply By: Ron N - Friday, Feb 26, 2016 at 18:58

Friday, Feb 26, 2016 at 18:58
The older, lower pressure injectors will last a lot longer, than the current, very high pressure, common rail injectors.
The reasons are simple. The older engines injected once per power stroke - the current piezo-electric injectors inject multiple times on a power stroke to improve fuel combustion and economy, and to reduce diesel injection "clatter".

The current piezo-electric injectors have multiple orifices, whereas a lot of the older injectors have only one orifice.
Multiple orifices means finer orifices, and therefore a higher chance of blockages via wear material from within the fuel system, and via carbon from combustion.

Current injectors operate at much higher pressures, therefore operating clearances are even finer than the old-style injectors (which often had 1/10,000 inch clearance between moving parts).

I was in an Isuzu dealership recently and they had a huge advert on the counter, with accompanying comprehensive literature, showing how important it is to ensure that the newest injectors are comprehensively cleaned by the dealership, using factory equipment, every 100,000kms, to ensure best injector performance.

In essence, the three factors that guide you towards injector servicing are hard starting, excessive black exhaust smoke, and worsening fuel consumption.
However, in the case of the exhaust smoke check, you need to have someone following you to determine just how bad your black smoke problem is.

Some black smoke under hard acceleration is allowable, but black smoke on a steady throttle is not - and neither is black smoke when pulling a steady load with a steady throttle, allowable.
Emitting visible black smoke for 10 secs or longer is enough reason to have your vehicle defected, according to most State traffic regulations.

I would not be replacing injectors at 100,000kms unless the engine definitely showed signs of hard starting, increased fuel consumption, or increasing levels of black smoke.

Valve clearance adjustment is a simple maintenance job that SHOULD be done every 100,000kms.
You will often be surprised at what a difference a valve clearance adjustment will make, to performance.

Cheers, Ron.
AnswerID: 596704

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