Injector service life.

Submitted: Wednesday, Jan 21, 2009 at 15:52
ThreadID: 65308 Views:5974 Replies:6 FollowUps:3
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There are many queries about how many km's before diesel injectors require service, and I also am just as curious.
Curious, because from personal experience injectors in heavy haulage trucks, earthmovers etc. can do massive distances, 1000's of service hours without losing injector performance.

I have 3 diesel vehicles:
S111 2.25 1976 Landrover trayback (155000km.)
Hzj 1997 75 s. L/Cruiser trayback (215000km.)
300tdi 1998 Discovery (178000km.)

The old Landy these days runs a bit rough on idle, but works hard enough (yeah, I know, its a Landy!)
The L/C and Disco run perfectly, good economy, easy starting, no smoking etc. without the injectors ever having been disturbed.
The L/C being indirect injection compared to the Disco. direct injection, seems to make no difference to how they run.

Where are differences (if any) between these and the first mentioned?
Do we tend to overservice our 4wd's when they do not require it?

I think it will be a while yet before I start pulling things apart.
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Reply By: Ozhumvee - Wednesday, Jan 21, 2009 at 16:49

Wednesday, Jan 21, 2009 at 16:49
I think it also depends on the actual use of the engine, engines in trucks are usually running continuously, like a taxi, 8 + hours running every shift which stops the cold start wear and everything is running at optimum temps and is serviced regularly.
The average 4wd in private hands if used like a car does lots of short runs, stops and starts, sitting in traffic etc which increases wear and shortens service life.
I decided over 20 years ago that it was better to buy an older car for the around suburbia use and keep the 4wd in the garage for weekends away and longer trips. I've never had the pump or injectors serviced on any of my diesel cruisers, usually takes ten years to get up around 200k and then I sell it and buy a younger one.
Do the servicing at the required intervals, change fuel filters at regular intervals, keep the aircleaner element in good nick and only try to buy known good clean fuel and they run ok for years.
A diesel engineer told me years ago that if you got them checked/cleaned and adjusted at regular intervals like 70 - 80k they would last for probably upwards of 250k before requiring new tips, if you did nothing till 250k then they will still need new tips but you may have suffered a decrease in economy and performance for the latter 150k.
That of course applies to the old style diesels where the injectors are serviceable, the new common rail electronic ones are not usually serviceable and have to be replaced at huge expense.
1996 Oka Motorhome

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AnswerID: 345383

Reply By: Member - Redfive - Wednesday, Jan 21, 2009 at 16:59

Wednesday, Jan 21, 2009 at 16:59

Every 100,000kms is the go for a L/Cruiser

AnswerID: 345386

Reply By: Member - Mfewster(SA) - Wednesday, Jan 21, 2009 at 17:15

Wednesday, Jan 21, 2009 at 17:15
A diesel mechanic once told me that the greatest shortener of injector life in 4WD and diesel cars was drivers wanting them to start like cars. He said they will fire up on quite short prewarms and most drivers tend to underwarm them before driving off and this considerably shortens injector life. He suggested making sure the full gloplug warm up time was always used, plus 5 seconds more.
AnswerID: 345390

Follow Up By: furph - Wednesday, Jan 21, 2009 at 18:40

Wednesday, Jan 21, 2009 at 18:40
An interesting comment Mfewster, that is something I have always done.
Our current excavator, Komatsu 30 tonne. is a very simple motor mechanically but has a comprehensive electronic control system as such that when first start for the day it runs at a medium idle. You cannot do anything to increase revs or start operating until the electronics says so.
If whilst working you stop and idle right down, after about 30secs. the idle speed will be electronically increased to about 1500rpm. (ie: no prolonged idle)
This machine has now over 8000hrs. up, starts, runs, performs like a new one. And has never had one thing done or replaced except normal oil and filter services. (sorry,we did replace some leaking "o" rings on the main valve assembly).
Thanks furph
FollowupID: 613373

Follow Up By: Member - Kiwi Kia - Wednesday, Jan 21, 2009 at 19:52

Wednesday, Jan 21, 2009 at 19:52
I can't see any possible reason to say that engine handling (warming up & running down time) will alter the life of an injector. The erosion of the nozzle (effecting the spray pattern) by the friction of the fuel passing through it and the spring getting tired would be the main things affecting injector performance.

FollowupID: 613387

Follow Up By: Member - Mfewster(SA) - Wednesday, Jan 21, 2009 at 20:39

Wednesday, Jan 21, 2009 at 20:39
I don't claim any expertise in this. I'm merely passing on what I was told by a diesel mechanic. The full story. I had a diesel Peugot. I had discovered that I didn't have to wait the full glo plug warm up time before cranking it over and it the fired up and away I went feeling pleased that I hadn't wasted that time and battery drain warming the glo plugs. After a few months, big problems, which turned out to be shot injectors. The mechanic's full story was that if the temp wasn't high enough, the compression might get the fuel to fire but the fuel didn't burn completely leaving carbon build up around the injector which progressively accumulated and shot the dispersal from the injectors and eventually stuffed them. True? I don't know, but it sounded plausible. Since then I have been very careful to thoroughly prewarm and then build up temp gradually in my various diesels and I haven't had an injector problem since.
FollowupID: 613393

Reply By: autosparky - Wednesday, Jan 21, 2009 at 19:59

Wednesday, Jan 21, 2009 at 19:59
pre 96 with australian diesel it had a high sulphur content and it was advised to check injectors and delivery valves every 100000
todays diesel is low sulphur (so less corrosion around the injector nozzle) but some injectors as with direct injection may not have to be checked at 100000.
AnswerID: 345410

Reply By: TerraFirma - Thursday, Jan 22, 2009 at 12:55

Thursday, Jan 22, 2009 at 12:55
The big concern nowdays is the common rail computerised injectors vs the older mechanical style. To me the mechanical style injector is a winner in certain enviroments, you can service it easily and keep it working optimally or buy a new one affordably. I am being told the newer common rail injectors are not serviceable albeit mine were cured by soaking overnight to address a rough injector as apposed to buying a new one for $1000 or thereabouts.

I don't like the idea of injectors not being serviceable and then asked to pay ridiculous prices for a new one. To me common rail technology does not justify the price hike nor the serviceability restrictions, I can hope this changes..

AnswerID: 345498

Reply By: TerraFirma - Thursday, Jan 22, 2009 at 13:01

Thursday, Jan 22, 2009 at 13:01
Interesting site on Common Rail Diesel, seems to be a push for a service centre in Brisbane.

AnswerID: 345500

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