High Mileage Diesel Injectors and Thoughts...

Hey Guys and Gals, Today, I changed my diesel injectors... it has 205,000 miles on it. The job is fairly easy... just like changing your spark plugs.
However, I now found my culprit in cold start idling problem and poor fuel mileage ( I was getting like 27 MPG, only). Yeah yea yea, 27 is still good eh? No, it is not. At a couple of times, I was running 24 or 25 MPG.
My car is rated 27 city and 35 highway. Yet, my car only gives me on low end all the time. When I first got it, it ran real good and got 34.5 MPG on highway. Not anymore.
Yes, additives helps and boost the fuel mileage, but I want my car to run good all by itself. So I decided to change my fuel injectors. I started with #6 cylinder and work my way toward #1. There was carbon deposits on every injectors, but at #2, I got a chunk of carbon cake... no wonder.
Then to #1 cylinder... WHOA! Monster carbon cake. I can't believe it. No wonder my cold idling is erratic and fuel mileage is not good... I don't think it is possible to clear out that carbon cake with Lubro Moly Diesel Purge... not that big... no freaking way.
So with that in mind, it takes a bit of time to pull out the injectors, but it was easy enough... especially with older MB diesel engines where it is right there in front of you. Mine was recessed and required special socket tool.
I am thinking... I know alot of you got high mileage on your engine. If you have some problem or you simply got time, you should pull out your injectors and clean out those carbon cakes if any. While you do that, you should change out the injectors... older diesel engines are like only $35 a piece rebuilt. That's cheap when you need only 5 or 6.
Mine is $55 a piece so that's $330 for set of 6. In any case, I want to run WVO in spring so I want good injectors first... plus with my problems, I did the right thing and can't wait for spring to run WVO full time.
P.S. Always replace the injector heat shield washer and make sure it is right side up! These are cheap online.
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I forgot to add a couple more things...
With the price of the injectors in mind, the amount of money you spend to 'purge' out those high mileage injectors... it just doesn't pay. I think I spent nearly $160 trying to get my injectors cleaned... so that's alot of wasted money, diagnostic effort and time for high mileage injectors.
Rebuilding your own injectors can save some money... but the time you spent may not be worth it... so a factory Bosch rebuilt injectors are real deal. They are tested and guaranteed. Some of you just got alot of time and wants to learn... please do so. I would do that if I could save money too... in my case because of my type of injector that is only used for 2 or 3 years, my saving is none. I also don't have much time either.
I remember some of you goes to PAP (Pick A Part) yards... and said most of those cars has rebuilt injectors put in and dirt cheap too... It's a gamble, but if you feel lucky... do it. Have fun!
In any case, just a thought I should share with all of you diesel heads.
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Tiger wrote:

Maybe you should have added that WVO is waste vegetable oil. A wikipedia page for starters is at http://en.wikipedia.org/wiki/Straight_vegetable_oil
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Hey Juergen! It has been a long time since I saw you here... or your mbspy website. How are you doing? What is your latest MB ride?
If I recalled correctly, you had a 240D?
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On Fri, 07 Mar 2008 18:07:54 -0500, Tiger wrote:

Hi Tiger, Your post has me thinking that I ought to seriously consider replacing my injectors. I can't say that I have much in the way of cold starting problems on the '87 SDL300 (305,000miles), but with that extra 100K mile over yours, I should check it out. Most of my driving is two lane high way with stops about every 3-4 miles for cross roads. Average fuel economy is around 25mpg. We have had some coldish nights over last two months that the old beast didn't really care for, but started with a single glowing of the engine. Some complaints, but settles down to even idle in 15-20 seconds.
--
Cheers, Kurt

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Hey Kurt, My friend got the same car... he didn't change his injectors yet... I think he has 240,000 miles by now... He said he gets around 27 or 28 MPG. Most of the time he drives highway.
He racks up about 30,000 miles a year driving. And he does it over 2 cars...
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I got 350,000 miles out of my original injectors on my 1982 300TDT, and I got a pretty consistent 27 mpg for hundreds of thousands of miles. I replaced my injectors and then the engine went to hell in the next 40,000 miles, but it was probably just a coincidence. I also changed to synthetic oil about that time, but again, probably just a coincidence. When I had the engine remanufactured at 396,000 miles Mike at Metric Motors discovered several cracks in the head he thought were likely from overheating at some time.
But now I have had my engine remanufactured at Metric Motors in Canoga Park, CA and the engine runs great and I got 31 mpg on a recent 2,000 mile trip to Denver and back from my home here in Eastern California. You cross at least 20 mountain passes, each way, on that trip too. I was able to fill up with 100% biodiesel in Delta, UT at a Sinclair station there, and my car ran great on it.

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Anyone here have actual experience on how good Bosch rebuilt diesel injectors are? I've seen complaints on other boards indicating that Bosch's are manufactured in a variety of countries now and that none are being done in Germany. It seems those made in India are problematic with reports of people bench testing units right out of the tox and finding either pop pressure or pattern problems.
I need to do something with mine and am trying to figure out what to do. Also, do most people just exchange the whole injector and then trust that the pop pressure is set correctly and they are all within spec, or do they do a bench test? Do most shops bench test them or just put them in? Seems if you have access to a tester, the best thing to do is just replace the nozzle instead of the whole unit and then test and adjust them if needed. Of course the problem with this is the testers aren't cheap or readily available. I'd also consider sending them out to a shop anywhere in the US that would test and rebuild my original ones so if anyone knows of such a shop, let me know.
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I did buy a bench tester but it didn't work and I didn't want to wait any further so I just installed my Bosch rebuilt injectors.
I know the report you heard and saw... but that was on diesel giant and only one case... Bosch gives you warranty on their injector... so if their injector blew your engine apart, they owe you a new engine.
I can live with that.
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I wasn't as concerned about low quality injectors out of the box blowing the engine apart as I was with them potentially being no better than the ones I'm replacing. Although I have seen reports where if the injector is real bad, it could burn a hole in the piston.
The reports I saw were on the forums on mercedesshop.com, where there seemed to be considerable agreement that the rebuilt Bosch ones had quality issues. But I'm also not sure what other real alternatives there are.
Where did you find the tester, why doesn't it work, and how much did it cost?
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Plus 4 MPG is awesome!
I want to get mine to 35 MPG... as it was when I first got the car.
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On Sat, 08 Mar 2008 11:08:04 -0500, Tiger wrote:

I've been having some DNS problems getting through to the newsserver for about a week, hence the slowness of my reply.
I'll certainly look into changing out the injectors. I used to get ~27-28mpg consistently. Only changes are fuel filters, filter/fluid in tranny, minor cleaning and belt replacement, and some body work needed when I got dinged one night by a blonde on a cell phone who didn't see me.
--
Cheers, Kurt

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