D-Jetronic fuel injectors for W109 300SEL 3.5: need advice here what to do

[werminghausen]

I have my Bosch injectors out and I see that one of them at least has a cracked tip. The yellow plastic cylinder that sticks in the intake has a crack. I don't know if this affects the function of the injector.
Also all the injectors have some wear at this yellow tip cyclinder. I guess it is from movement in the rubber sleeve.
Someone recommended that I should have them tested and cleaned which costs about $ 17 plus a new hose = $ 21 per injector.
But... there is still no guaranty that the injectors are good. If not it might me more expensive.

There are alterntive reman injectors out for only a little more...like $ 25
GB REMANUFACTURING Part # 85213101?

I also heard that some Nissan injectors would fit right in the MB.
Nissan or Datsun Z 280 turbo injectors FJ23?

So my question is: what would you do?

[JeffreyNMemphis]

I would go with the remanufactured Bosch injectors (for four dollars more than cleaning your old injectors). Does the reman injector require a "core"?

[Gurunutkins]

you can clean them yourself in an ultrasonic cleaner using a seafoam blend with kerosene and then flow rate them as well. I have a test setup with a CIS pump and a djet regulator set at 32 psi and fire them into calibrated test tubes. Its not for the faint of heart and for the $25 each from rock auto I would probably advise that route if you are not pretty handy with mechanical stuff.

the end cap is replacable - its called a pintle cap and I buy them by the bag (100) for a dollar each from dr injector or somewhere similar. there is a long nylon mesh basket in the top of the injector which should also be pulled and cleaned

I am currently converting one of my megasquirted engines from the bosh 036 injectors to the 290ml JECS injectors off a couple of nissan zx300's. remember with the nissan injectors that the number on the body is a date and production facility stamp and does not relate directly to flow rate. flow is determined by the colour of the body not the number.

there are a couple of pics below of how I do it but I use mt stimulator to fire the injectors and you are playing with gasoline under pressure and the possibility of electric sparks!








cheers
Barri

[Benz Dr.]

Rube Goldberg is alive and well!

Looks like it could work but man are ou taking chances of getting hurt......

[werminghausen]

Originally Posted by Gurunutkins

you can clean them yourself in an ultrasonic cleaner using a seafoam blend with kerosene and then flow rate them as well. I have a test setup with a CIS pump and a djet regulator set at 32 psi and fire them into calibrated test tubes. Its not for the faint of heart and for the $25 each from rock auto I would probably advise that route if you are not pretty handy with mechanical stuff.

the end cap is replacable - its called a pintle cap and I buy them by the bag (100) for a dollar each from dr injector or somewhere similar. there is a long nylon mesh basket in the top of the injector which should also be pulled and cleaned

I am currently converting one of my megasquirted engines from the bosh 036 injectors to the 290ml JECS injectors off a couple of nissan zx300's. remember with the nissan injectors that the number on the body is a date and production facility stamp and does not relate directly to flow rate. flow is determined by the colour of the body not the number.

there are a couple of pics below of how I do it but I use mt stimulator to fire the injectors and you are playing with gasoline under pressure and the possibility of electric sparks!








cheers
Barri

Hi Barri

I am impressed because I know you are a pioneer.
I am also interested to learn this stuff. On the other hand I just don't have the time to figure this all out.
If I go the way with the GB reman. injectors (I guess these are Bosch ones) then do you think there is good chance that a set of these would work fine?
If yes this would be the easy fall back option.

on the other hand the car was running ok..not great...with the old injectors. But I don't have the comparison. So if I decide to do the experiment would you sell me the parts I'd need to do my own remanufacturing? Do you think I can make my old injectors work...if I just have enough time? How do you adjust the flow rate on your injectors?
(I have built my own diesel injector stand for my SDL Diesel years ago and it was a great experience. However the gas test stand seems to be more challenging/dangerous and stinkier)

Third option: Do the Nissan zx300 ones just go straight into the Mercedes 3.5?...even with a different flow rate? Or can the engine handle different rate if the set is the same flowrate? New Nissan injectors are very cheap on ebay...like $140 for 6 injectors
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=160500451880&viewitem=&sspagename=STRK%3AMEWAX%3AIT

Martin

[Gurunutkins]

sorry Martin its difficult to give you a straight answer

you have a 3.5 m116 engine and the injectors in the rock auto catalog are for a 4.5 m117 engine they are bosch #280 150 036 and depending on whose figures you believe they flow anywhere from 395 to 520 cc/hr depending on pressure (28.5 to 42psi) my bosch book gives them 480 at 32psi.
the M116 engine in 3.5 format came with either 0280 150 024 or 280 155 203 injectors which according to my book run at 310cc/hr at 28.5 psi.

all of these injectors are low ohm at about 3.2 ohm

the nissan injectors will bolt straight in on your fuel rail and the 300zx are rated at 280cc to 310cc/hr at 28.5 to 32psi and are 2.7 ohm resistance so they should work just fine. but I have not done it myself so I dont know - I can tell you they would be better than using the 036 injectors that you see on ********.

I use the brown top nissan 300zx injectors on their own rail and then a piping bender to bend the rail to get the holes to line up. I also use a megasquirt controller to control them

lastly remember if you do use the nissan ones then replace all of your lines and push the pressure to 32 to 35 psi. I use the proper braided silicone pipe at 7.5mm and only full clamps. If I can help let me know I should be around the forum more this year and yes if you decide to clean yours I can send you pointers and parts. below are the nissan injectors, and piping I use
cheers
Barri

[werminghausen]

Originally Posted by Gurunutkins

sorry Martin its difficult to give you a straight answer

you have a 3.5 m116 engine and the injectors in the rock auto catalog are for a 4.5 m117 engine they are bosch #280 150 036 and depending on whose figures you believe they flow anywhere from 395 to 520 cc/hr depending on pressure (28.5 to 42psi) my bosch book gives them 480 at 32psi.
the M116 engine in 3.5 format came with either 0280 150 024 or 280 155 203 injectors which according to my book run at 310cc/hr at 28.5 psi.

all of these injectors are low ohm at about 3.2 ohm

the nissan injectors will bolt straight in on your fuel rail and the 300zx are rated at 280cc to 310cc/hr at 28.5 to 32psi and are 2.7 ohm resistance so they should work just fine. but I have not done it myself so I dont know - I can tell you they would be better than using the 036 injectors that you see on ********.

I use the brown top nissan 300zx injectors on their own rail and then a piping bender to bend the rail to get the holes to line up. I also use a megasquirt controller to control them

lastly remember if you do use the nissan ones then replace all of your lines and push the pressure to 32 to 35 psi. I use the proper braided silicone pipe at 7.5mm and only full clamps. If I can help let me know I should be around the forum more this year and yes if you decide to clean yours I can send you pointers and parts. below are the nissan injectors, and piping I use
cheers
Barri

Hi Barri,
Thanks so much.
I have the injectors with protection sleeve (I guess the yellow plastic at the tip that is shot) and double sealing edge at the inlet fitting. Part number is 0280150034.
I have removed the 'protection sleeve' and tried to clean the strainer. It was full of gunk. Can I remove the strainer?
Although the bodies of my injectors are somehow corroded I think I could give it a shot and repair them before I wonder off in unknown worlds or Nissan...I might get lost there. It would be great if you could give me hints and instructions on how to get the original injectors back to a decent life.
Best, Martin

[Mike D]

Barri. Why are you using gasoline in your test set up? You just like living on the edge? Use mineral spirits instead. Not only is it less flammable but it will actually clean the injectors while testing.

[Graham]

When I cleaned and tested my injectors, I used a less flammable fluid - I used marine stove alcohol which I just happened to have and later carb cleaner or was it kerosene? My setup was even more Rube than barri's


More discussion here:
Djetronic pressure and injectors control

As barri said, the pintle caps are easily replaced (he helped me when I first did mine). I bought mine at dealer for low cost (I don't know if they will have yellow ones - does it make a difference barri?). I removed the screens by screwing in a self tapping screw and then pulling it out using vice (like pulling teeth!) I cleaned the screens in our el cheapo jewelry ultrasonic cleaner.

And again as barri said, make sure you get the proper injectors for the 3.5 - Some remans come from asia so the yellow ones may be available. Those on line ones are not always Bosch - I read where others ordered and did not get Bosch. There are many on-line places selling reman injectors so check around. BTW, none of these are really rebuilt - probably just cleaned and checked for flow. If you have the time and don't want to do it yourself, I would just send existing ones to someone like this and let them install the pintle caps and new hoses. My 1972 vintage injectors seem fine.

http://www.witchhunter.com/index.php4

Some other links:
http://www.cruzinperformance.com/fuelinj.html
http://www.injectorcleaning.co.uk/flow.htm
http://www.rceng.com/technical.aspx
http://www.motec.com/fuel/injectors/
http://www.ineedparts.com/index.php?target=products&product_id=2154
http://ausinjection.com/catalog.html
http://www.fuelinjector.citymaker.com/Prices.html
http://www.fuelinjector.citymaker.com
http://www.fuelinjector.citymaker.com/MERCEDEZ_BENZ_FUEL_INJECTORS.html

Haven't dealt with any of above - just collected links before my DIY job!

[JeffreyNMemphis]

Barri,

You are my hero! Thank you for sharing your experience and wisdom. I wish I knew more about fuel injection and Megasquirt.

Jeffrey

[Gurunutkins]

Hi Guys
I have a knack for expressing myself badly sometimes

I use a seafoam:kerosene blend to clean the injectors in the ultrasonic cleaner. I then run my system with kerosene through the injectors (and yes you can flush from the tip of the injector as well).
however our injectors are sized very large for our engines and horsepower so they run at very low pressure. the 036 injector for example is run at optimum spray pattern at 3 bars (43.5psi) yet our system runs at 28+psi. I find that if i run the system with anything other than gasoline at 30psi I get malformed spray patterns (and drips forming on the pintle caps) which throw out the calibration - so for the calibration step I run gasoline into graduated tubes. I tried with kerosene and kerosene diluted with spirits but had to run up to almost 50psi to get decent spray patterns.

I am hoping with the smaller nissan injectors in my M116 engine that I can push the pressure up to 40psi and get better spray patterns and atomization and hopefully push my power and economy up a little more. I currently run the 350 at 20mpg and the 450 at 17-18mpg but hope to get another 20% on that with the smaller injectors which should be easier to tune at higher pressures.

Graham and i used to chat quite a bit about what was possible with these systems - they can be refined quite a lot with more modern controllers - if you dont mind the franken merc concept . Jeffrey - bet you 50 cents that after reading the megasquirt manual for 30 minutes you would be building a system with no problems - its always the first step that is most difficult - as i remember Mike has his running on TBI's in just a few weekends.
I look forward to spending a bit more time on the forum again as i think my traveling days are over - i'll see what new employment brings and I may eventually get the time to convert this door stop into a MS monster with EDIS

cheers
Barri

[Graham]

Originally Posted by Gurunutkins

I am hoping with the smaller nissan injectors in my M116 engine that I can push the pressure up to 40psi and get better spray patterns and atomization and hopefully push my power and economy up a little more. I currently run the 350 at 20mpg and the 450 at 17-18mpg but hope to get another 20% on that with the smaller injectors which should be easier to tune at higher pressures.

Hi barri,
Sounds like an economical way of trying lower flow injectors. If I can find 8 Nissan injectors cheap, I might try that just for fun.

In my case, I will have to adjust the MPS and ECU but the wideband AFR meter should help get the settings right (whatever that is!). Problem is that engine runs best when set on rich side, so mpg has to give

Car is stored at present, but next project is to install a Flamethrower coil.

No idea what mpg I get, but it is much better than it once was - I can no longer see the fuel gauge moving while driving.

BTW, with MS, do you inject just before each valve opens, or is it like D-jet with only one of a pair of valves getting gas at just the right time?

[Tony H]

I'm pretty sure MS batch fires all injectors at once. According to their research there is almost nothing gained by sequentially firing the injectors-except when the engine is idling it provides a smoother idle.

[Gurunutkins]

had to go to NY - sitting in the airport waiting to go home (late as usual).

the MS has 2 injector circuits so fires 4 injectors at a time on my set up. I fire the 2 inner left and 2 outer right on one circuit and the opposite on the other. MS lets you fire multiple times in each engine revolution. so in my case i fire the injectors twice each revolution - each fires half the needed fuel for a full revolution each time. This gives me a very stable idle.

You have to remember that with individual injecton - i.e. an injector in front of each cylinder (multipoint) - that the injector still fires mainly into the plenum and that at most - unless you have a broken injector - only 5 to 7 % of the fuel from a particular injector goes into the cylinder associated with it at idle. a lot less at higher revs, thats why TBI's are often better as they inject at the throttle body directly into the plenum "cloud"

I have seen cases where a single injector breaks and fires a full stream of fuel into one particular cylinder but its an unusual occurrence. Generally you just run rich or lean in the plenum cloud.

MS does have some programming for sequential injection but after the studies showing how little fuel from each injector goes into its related cylinder it gets used very little. Also its a lot more complex to do

Martin I will send the stuff tomorrow - I will only get home very late tonight or in the wee hours tomorrow.
cheers
Barri

[Graham]

Thanks for the explanation of how MS injects. Gosh the original Bosch system has twice as many injector circuits as MS

I am surprised that such a small % of fuel injected near a certain cylinder would end up in that cylinder. That fuel would have to flow back up the intake runner and then find it's way down another runner to a different cylinder - What causes that? Maybe pulsing from the valves?

As you can tell, I don't know beans about this. My diesel injectors squirt fuel right where it is needed