Injectors

[russelljones48]

It took me quite a bit of time to find something official that "proves" that the later A000 078 1123 injector replaces the earlier A000 078 0723 230SL injector.  Here's what a vendor (https://eeuroparts.com/) sent me:

[Pawel66]

There is nothing like that in the EPC, but there are other systems at Mercedes with more replacements options. Best: call the dealer and ask them to check if one can replace the other.

[mdsalemi]

Before investing in new injectors you should build/borrow or otherwise use the well known injector tester. It can clean a dirty injector and unclog a clogged one. It cannot restore every injector but I’ve seen it restore a number of them.

There are some members here who have bought new Bosch injectors and found many new ones basically unusable.

The ones you have may be perfectly fine after a good cleaning in the tester.

https://mercedessource.com/store/cis-gas-fuel-injector-spray-pattern-tester-and-nozzle-cleaner

[russelljones48]

Mike,

The old injectors have been tested and double checked..   all but 1 didn't meet specs.  The "early" injectors (R1) are quite hard to find and almost twice the cost (around $200) so we've decided to order a complete set of the new (or R2) injectors as being the best course of action.  The new set will be tested before they're installed.  I've read through most of the posts here and it "looks like" there have been some failed "R2" injectors but that they are the replacement Bosch recommends..   I've not found any descriptions of "what's different" but given that the change occurred at the same time the 250 was introduced as well as "smog" requirements my only guess is that they may atomize better...  maybe they add a bit more fuel for the larger displacemnt - dunno..  testing will tell.   

[mdsalemi]

Mike,

The old injectors have been tested and double checked..   all but 1 didn't meet specs.  The "early" injectors (R1) are quite hard to find and almost twice the cost (around $200) so we've decided to order a complete set of the new (or R2) injectors as being the best course of action.  The new set will be tested before they're installed.  I've read through most of the posts here and it "looks like" there have been some failed "R2" injectors but that they are the replacement Bosch recommends..   I've not found any descriptions of "what's different" but given that the change occurred at the same time the 250 was introduced as well as "smog" requirements my only guess is that they may atomize better...  maybe they add a bit more fuel for the larger displacemnt - dunno..  testing will tell.   

If ONE R1 injector didn't meet specs, shouldn't be that hard to find ONE good used one? But probably a good idea to have the full set of six either all R1 or all R2 and all working properly.

Mauro from Messina, Sicily, bought a full set of the newer ones and most were no good. He returned them...I think you could find his posts on the matter.

[Jonny B]

I am sort of curious about the cleaning process (I have a bunch of injectors acquired over the years) so I looked at the link posted for mercedes source. The list of applicable cars does not include the 113s.

Is there an adaptor to use for these (the 113 units)? Or is it just not mentioned, and it does work with those? And I am assuming the 111 -112 etc.

[yves]

I used the mercedessource kit with succes. The pattern of the spray was good after +- 20 press actions
Now the kit is waiting .... for a use in 2040....

[mdsalemi]

JonnyB, Jim Villers had his setup at the Charlottesville PUB in 2017. He cleaned and tested many injectors, and I remember helping at least one member removed them from his car and replace them. It looked pretty identical to the one shown from Mercedessource, basically some connectors, hardware, a supply of cleaning fluid, and a gauge/pressure pump.

I don't have any to check but if YOU do it might be worthwhile to build one.

The cleaning process basically puts a little to a lot more pressure on the injector than it gets from the FI pump. This can "free up" any stuck parts, but not 100% of the time. I remember watching as we pumped and finally a stuck injector "popped" and began to spray. Then continued spraying and pumping allowed the fluid to clean the injectors.

This is a great PUB topic and I think we'll do it again for 2025 if we have a PUB tech session...

[dirkbalter]

I am sort of curious about the cleaning process (I have a bunch of injectors acquired over the years) so I looked at the link posted for mercedes source. The list of applicable cars does not include the 113s.

Is there an adaptor to use for these (the 113 units)? Or is it just not mentioned, and it does work with those? And I am assuming the 111 -112 etc.

https://mercedessource.com/store/bosch-mechanical-fuel-injector-mfi-tester-and-cleaning-kit

Jon, I have one of these test kits. It's more for testing rather than cleaning. For me an ultrasonic bath together with soaking and scraping... worked on some of the injectors.
You can use it if you want to get into it.

[russelljones48]

Mike,

Here's my thought process.  They are a different part number, for a different sized and tuned engine (although the 250 head will fit the 230) and therefore probably slightly different injectors.  So our decision was to go with 6 of the same injectors - not to "mix" early and late since the assumption is that the early and late injectors won't behave exactly the same.  Since they are also designed to feed a later, and larger engine we also surmise that they might offer more performance for the smaller 230..  But we don't really know their delivery characterisitcs until we test and tune..  I did read the post you mention and that set was returned, deemed defective, and replaced with the same part number satisfactorily..  BUT as I said above they'll be tested before installation and potentially tuned afterwards.  Lastly was the $$$$  - early are running about $200 - 250 and the late are $100.  6 late are $600 and 5 early would be over $1000..  the next owner may thank me for the later and more available parts   

[Benz Dr.]

Either style injector will work in any Pagoda engine. The injection pump determines how much fuel is delivered, not the injectors. The R1 and R2 injectors have different spray patterns with the R1 being more conical in shape. I prefer the R1 when I can find them.

[russelljones48]

Thank you.  All of my injectors were retested and although the patterns look good and they chirp as desired the pop pressures are below the minimum of 15 atm or 220.4 psi, per the gauge they pop at 200-210 psi.  Gauge tested (actually reads a little high) as a precaution and the conclusion is that the injectors all pop below spec...   

[lurtch]

This is a re-post of the bench check apparatus I designed and used used in 2020. The Vimeo link is still active.

Larry in CA

_________________________________
Hello All

I have been experiencing some rough running on start up along with indications of
a overly rich mixture. After verifying that all the standard mechanical engine settings are satisfactory,
I decided to check out the more difficult one: bad fuel atomization at the tip of the fuel injector. My suspicions were confirmed because three of my injectors had poor dispersion patterns.

 I was able to find a cheap hydro-static tester on Amazon for about US $ 50.00.

I fabricated a holding fixture, silver-soldered a tubing joint, and assembled some fittings and it was ready to start testing
individual injectors.

The book value pressure required to lift the injector pintle is 213 - 256 psi. (15kg/cm2 - 18kg/cm2)   At these pressures a good injector will disburse a very good spray pattern. (see videos) There is an internal filter (not accessible) that can distort the flow of fuel which causes this disruption in the spray pattern. (see videos)     https://vimeo.com/385872636

Regards,

Larry in CA

[russelljones48]

Larry,  I had watched this video and found it quite informative.  My R1 injectors have had 2-3 cleanings were tested on a device similar to yours - the patterns are now alll acceptable but they "pop" or fire at a lower than spec pressure.  As mentioned above.  To us that indicates that the springs are probably weak and the injectors need replacement.  An "early" injection in the air/fuel stream likely means that it's not optimal to valve timing..    that can compromise performance.. 

AND THANK YOU Dr. Benz for confirming that the R2 injector set will work and your preference.  Makes our decision to replace the entire set at least rational...  and hopefully this stream will help those in the future that have my same challenges. 

[Benz Dr.]

Thank you.  All of my injectors were retested and although the patterns look good and they chirp as desired the pop pressures are below the minimum of 15 atm or 220.4 psi, per the gauge they pop at 200-210 psi.  Gauge tested (actually reads a little high) as a precaution and the conclusion is that the injectors all pop below spec...   

I have no problem running injectors that open at 200 PSI. As long as they have a good spray pattern and don't leak, they are likely to work just fine.

 MB sets a lower limit of 150 PSI compression ( on a 280) before rebuilding an engine even though that same engine will run without issues. When they set those limits, they were not thinking about 50 plus years into the future where parts are now getting harder to source and these cars don't see a whole lot of driving. These guidelines were meant for MB dealers who would benefit from getting their customers to spend money on a currently driven car, not an occasional toy.

Save your coins for things you actually need like fuel, insurance, or tires.

[rosch]

Check my earlier post , search for  "injector rescue"
Got all my 6 injectors working again.
You might try it yourself. Nothing to lose...

[mauro12]

I can give you my experience when I rebuilt my fuel injection pump and injectors . Before rebuilding the pump , i took a breathe and I invested 1000€ for a set of new r2 injectors but the result was terrible . The car was running poorly  , no power , no acceleration at all . I put back the old one and the car came back normal. I’ve been refunded from mb.classic.de because they sent to bosch the injectors and they were actually defective from the factory . No other explanations from them apart for the refund .
The year after I sent the pump and injectors for a full rebuild to Hans fritzsche in Germany . He suggested me to replace my old injectors because the opening pressure is on the low side , about 207psi , the normal range should be from 220 to 260 . Also the residual pressure after 1 hour is low in 1 injector out of 6. The car is running perfectly but from cold it could be better with new ones . Also fuel economy I’m sure could be improved with a new set .
I decided not to buy so far because I’m scared to have the same negative experience but I’m not saying the all r2 are defective .
Any other experiences with r2 injectors?

[mdsalemi]

I can give you my experience when I rebuilt my fuel injection pump and injectors.

Great, detailed story, Mauro! Thank you for sharing.

Here in the USA, it’s a bit less costly and a bit easier to obtain a set of new R2 injectors. There are many suppliers of them, and the cost is generally less than $100 each… But if I changed mine, I would probably try to have them tested first!

One would expect that the defective ones you received were simply a terrible error on the part of Bosch.