Injector Replacement - PeachParts Mercedes-Benz Forum

NoSparkNeeded · #1 06-04-2009, 04:27 PM

My wife's 84 SD has approx 240k on it now. I recently did the timing chain. It starts just fine, runs just fine, except, she says it still feels low on power compared to what it used to feel like to her. It does seem a lot slower and less powerful than my 85TD. I've done all the things, i.e. banjo bolt, check timing, valve adjust etc. So since they have never been replaced, I figured it might be time for new nozzles. If everything seems fine except a lack of power,could just that single symptom with no others showing up be a case of worn nozzles? I'd sort of think other symptoms would have to present, like excess smoke, hard starts, rough running. So do you guys think it could be nozzles? I'd do a diesel purge, but if I need to do nozzles
anyway there'd be no point. I read here nozzles should be done about
every 100k anyway. What's your opinion.

oldsinner111 · #2 06-04-2009, 05:14 PM

on wvo run monarks clean every 50,000. On diesel or bio use monarks and clean every 100,000 and or replace.

latitude500 · #3 06-04-2009, 05:24 PM

I had the same issue with my 87 300SDL before I started running wvo, I was told that the injectors are wear items and they should be replaced every 100k. I ended up replaced all six of mine and having them balanced and what a difference they made in power and performance. It was like I was driving a new car. The idle was quieter and smoother. It was well worth the money to have them replaced. You’re going to want to purchase 5 rebuilt injectors and have them balanced by someone with a pop tester. Don’t forget to purchase the crush washers when you purchase your injectors. YOU CAN NOT REUSE THE ONCE YOU HAVE. The only down side is your going to have to purchase a special tool to remove the injectors. I know for a fact the tool that I purchased for my 87 300SDL is different then your 84SD. But it looks like a very large / long socket.

I wish I did replaced mine sooner.

Rebuilt Injectors 5 * 56.77
http://www.allpartsexpress.com/ShopByVehicle.epc?q=1984-MERCEDES--BENZ-300sd--/--L5--998cc--3.0l--Diesel--Fi--Turbo-Diesel--Injection&yearid=1984%40%401984&makeid=MERCEDES+BENZ%40%40MERCEDES+BENZ%40%40X&engineid=1194038%40%40300SD++%2F+L5%2D2998cc+3%2E0L+DIESEL+FI++Turbo%40%40300SD&catid=Diesel+Injection%40%40Diesel+Injection&subcatid=Fuel+Injector%2C+Rebuilt@@Fuel+Injector%2C+Rebuilt&mode=PA

Fuel Injector Seals 5 * $1.65
http://www.allpartsexpress.com/ShopByVehicle.epc?q=1984-MERCEDES--BENZ-300sd--/--L5--998cc--3.0l--Diesel--Fi--Turbo-Diesel--Injection&yearid=1984%40%401984&makeid=MERCEDES+BENZ%40%40MERCEDES+BENZ%40%40X&engineid=1194038%40%40300SD++%2F+L5%2D2998cc+3%2E0L+DIESEL+FI++Turbo%40%40300SD&catid=Diesel+Injection%40%40Diesel+Injection&subcatid=Fuel+Injector+Seal@@Fuel+Injector+Seal&mode=PA

Total Price:

Rebuilt Injectors 5 * 56.77 = $283.85
Fuel Injector Seals 5 * $1.65 = $8.25
= 292.10 + plus shipping

NoSparkNeeded · #4 06-04-2009, 05:37 PM

Well looks like I'll just take the plunge and replace. I did my 85 TD
without any special tools though. I replaced the nozzles myself.
Because they were NOS Bosch, that they were probably exactly
like the old ones down to the micron, that taking the chance not
pop testing would probably be OK, and it was. The 84 will be getting
Monarks. There might be too much mfg. variation to not pop test, so
I'm thinking of buying a rebulit and popped set from Bryan here on this board, and sending him back my cores, so there isn't any downtime for her. I just wanted some opinions on the symptom, and the general
longevity of the nozzles.

DieselAddict · #5 06-04-2009, 06:25 PM

I would do a Diesel Purge and test the injectors before replacing them. It could easily be something else, like a clogged tank screen. Don't just throw parts at a problem. Try the cheaper/easier stuff first.

latitude500 · #6 06-04-2009, 06:36 PM

That is good advice about using the diesel purge and making sure it's not something else. But after 240k on a part that only lasts 100k, they are going to need to be replaced.

Quote:

Originally Posted by DieselAddict

I would do a Diesel Purge and test the injectors before replacing them. It could easily be something else, like a clogged tank screen. Don't just throw parts at a problem. Try the cheaper/easier stuff first.

DieselAddict · #7 06-04-2009, 07:53 PM

Injectors can last much longer than 100K. That mainly depends on the quality of fuel that flows through them and the type of driving. Where did you get the 100K interval idea? Some parts website?

NoSparkNeeded · #8 06-04-2009, 09:35 PM

What I meant was not entire injector replacement, but only the nozzle.
I've read in several places that MB recommends nozzle replacment
at 100k as a wear item. I'm pretty sure it was in this forum, but could
have been at dieselgiant. I believe they were quoting the FSM.

Scott98 · #9 06-04-2009, 10:09 PM

I don't think you are going to notice a performance increase after you rebuild your nozzles. I rebuilt mine after about 300k. Sure the engine is quieter, fuel economy appears to have gone up a bit and I'm glad I did it; but you aren't going to notice any huge performace gain. BTW, when I pop tested the old ones they were shot so if there was going to be a performace gain, I should have noticed.

You need to check other things first. Make sure your air filter is clean. Pull your tank screen, clean it and blow out your fuel lines. Change your fuel filters. Even run some diesel purge through the old nozzles. Do all of the simple cheap things first that are likely to zap your power rather than throwing money at new nozzles. I have nothing against new nozzles, I just don't think they are going to solve your problem.

Scott

charmalu · #10 06-04-2009, 10:30 PM

As far as the 100,000 mile replacement on the injectors, I heard that over
20 yrs ago long before I knew about MB Diesels.

Thing I was told, that high milage ones don`t spray an even spray pattern, and there can be hot spots on the piston. which can lead to in extreem cases of burning through the piston.

I have always replaced the ones on the Datsun every 100,000 miles as a matter of PM. Always runs good.

The MB when we first bought it I use to take it into a shop for Maintenance things I didn`t understand or know.(that was then, I are a expert now

) Had a miss in the engine a couple different times, and the mechanic just replaced the one bad injector. this happened two different times.

Iam thinking doing this then, we don`t have balanced injectors. new and older high milage ones. so I finally replaced all of them, got them from Rusty. that was before MB Shop.

The last time I was feeling rich

, I droped off 2 sets of injectors at a injection shop in Salinas. the guy wanted $375.00 to do the MB. told the guy to forget it.

It`s best to have BGKAST or CSEANWATTS (sp) to do it. they have a good price.

Charlie

Scott98 · #11 06-04-2009, 10:53 PM

Quote:

Originally Posted by charmalu

As far as the 100,000 mile replacement on the injectors, I heard that over
20 yrs ago long before I knew about MB Diesels.

Thing I was told, that high milage ones don`t spray an even spray pattern, and there can be hot spots on the piston. which can lead to in extreem cases of burning through the piston.

I have always replaced the ones on the Datsun every 100,000 miles as a matter of PM. Always runs good.

The MB when we first bought it I use to take it into a shop for Maintenance things I didn`t understand or know.(that was then, I are a expert now

) Had a miss in the engine a couple different times, and the mechanic just replaced the one bad injector. this happened two different times.

Iam thinking doing this then, we don`t have balanced injectors. new and older high milage ones. so I finally replaced all of them, got them from Rusty. that was before MB Shop.

The last time I was feeling rich

, I droped off 2 sets of injectors at a injection shop in Salinas. the guy wanted $375.00 to do the MB. told the guy to forget it.

It`s best to have BGKAST or CSEANWATTS (sp) to do it. they have a good price.

Charlie

There is not doubt that new injectors are good for the engine. The original poster, however, wanted new injectors to solve a performance problem.

DieselAddict · #12 06-05-2009, 12:45 PM

Given the hit-and-miss quality of new Indian-made Bosch nozzles, I'd strongly caution anyone against just replacing the nozzles as preventive maintenance. I really can't think of any reason not to test the nozzles first. By all means test them every 100K miles or even sooner if it makes you feel better, but there's a good chance the nozzles will still be good after 100K miles. Throwing away perfectly good nozzles, especially the original German ones, just makes no sense to me.

Diesel911 · #13 06-05-2009, 02:59 PM

Quote:

Originally Posted by DieselAddict

Given the hit-and-miss quality of new Indian-made Bosch nozzles, I'd strongly caution anyone against just replacing the nozzles as preventive maintenance. I really can't think of any reason not to test the nozzles first. By all means test them every 100K miles or even sooner if it makes you feel better, but there's a good chance the nozzles will still be good after 100K miles. Throwing away perfectly good nozzles, especially the original German ones, just makes no sense to me.

Since you bought up the Indian Made Nozzles I wanted to comment on the Nozzle swap with the same companies Nozzles and thinking that the measurements would be the same so you do not need to Pop Test them.

If they are the Origional Nozzles they were most likly made Germany. My understanding is that all of the new Nozzles of the 617 types are made in India. I sure would not expect the same dimensions from the Old to the New Nozzles; especially since they are made in a completely new country.

DieselAddict · #14 06-05-2009, 03:10 PM

I've done nozzle swapping on a few cars including pop testing and I didn't observe any huge change in pop pressure going between German, French and Indian Bosch nozzles. I've never had to adjust the pop pressure. However I've rejected some new nozzles due to a poor spray pattern and those can also have wildly varying pop pressures.

Scott98 · #15 06-05-2009, 03:13 PM

I used Monark nozzles on mine and they work great. I had to reset the pop pressure on only one of them; however, the old nozzle could have had the wrong pressure to begin with.

Scott