injectors

[natenate]

Hi
Just had my injectors tested in my 230sl. fortunately 4 out of the 6 are no good. my question is should i replace all 6? Or would be replacing the 4 not spraying correctly be enough? Was told that new ones would spray differently to the 2 that are working OK and that would effect the preformence of the engine therefore I should replace all 6 and as you know they're not cheap.
Thanks

[Jonny B]

Will be curious to see what others type on this. I have replaced single injectors on my 250 SL with no noticeable effect.

[280SE Guy]

I would replace all six and keep the two good ones as spares, but that's just my opinion.

[stickandrudderman]

Technically you have proved which ones are working correctly and which ones are not and so you can just replace the failed ones.
However, I always recommend changing them all at the same time since it is likely that they are all the original ones and so the ones that you don't replace have a high chance of failing soon after the already failed ones.
As you say, they are not cheap but then what is on these cars?

[wwheeler]

It depends on your pocketbook. If you have to park the car because you cannot afford to change all of them right now, by all means just change the bad ones. But as Stick pointed out, the others probably aren't far behind. An extreme example, but you get the point.

Same thing happened on my injectors. I went ahead and replaced them all. Then I had beans for supper for a few weeks......  

[66andBlue]

Changing only the bad ones is a decent choice, however, if you still have the original R1 injectors in your 230SL then you have the additional problem that they are NLA.  I believe mixing R1 and R2 injectors (which are available) is not a good idea.

[wwheeler]

Good thought Alfred!

[Benz Dr.]

Changing only the bad ones is a decent choice, however, if you still have the original R1 injectors in your 230SL then you have the additional problem that they are NLA.  I believe mixing R1 and R2 injectors (which are available) is not a good idea.

OK, I'll bite. Why?

[66andBlue]

Did YOU not make that comment somewhere?  
I may be dead wrong, but somehow I remember you mentioned that the spray pattern and/or the opening pressure settings are not different but the needle is?
Do the the two injectors not have different "guts"?
---
Added:
The guts are different, just found the info: The R1 injector needle is thicker, 1.8mm, while the R2 is 1.2mm and the latter also is "unguided" (ungeführt"):

[Rolf-Dieter ✝︎]

Gentlemen when I purchased my 280SL in May 2013 the previous owner told me he just changed 2 injectors and had a break job done on the car. Now since then I traveled over 4,000 Miles and so far no injector issues "Touch Wood"

[Shvegel]

Unless money is an issue I am a big fan of just "zeroing" out an item and forgetting it.  marginal injectors can cause rough running as well as warm start issues.  Another thing to consider is that in 5 years when the other 2 die the price for 2 then will probably equal what you would pay for all 6 today.

[alchemist]

Have you thought about cleaning the injectors by professional Diesel injector shops? This may save you $$$$. Many of us have tried this method with good results. If this method does not improve the injectors, I would replace the band ones with the same type. Google "diesel injector shops" in your area, they should be able to help you.

[Benz Dr.]

Injectors do wear out over time but they usually don't die unexpectedly. I've seen 50 year old units that are still working just fine - a lot depends on the history of the car. There is no reason to replace perfectly working units with new ones nor is there any real reason to fear mixing R1 and R2 injectors up. 

[Steven A]

Hi,

Whilst coming in late on this forum, a (very fundamental) lesson learnt the hard way re injectors.   

After completing a complete engine rebuild ($$) on a 1964 230SL, after 1000 kms noticed a touch of white exhaust smoke.   Changed valve stem seals etc looking for any source of oil getting into combustion chamber,  made no diffenence.   White smoke got worse...had to be oil related   Turned out one of the injectors was leaking, not enough to be noticed in engine performance/power/driveability, but washing the lubricant off the bore, scoring bore/rings......engine rebuild #2 as had to bore out the cylinder.  All good now (that was 5 years ago) with a lot of km's covered.

These days, whilst working on tuning up the injection system, the injectors come out and go to a diesel injector shop and check spray, no leakage and where possible, matching the injectors delviery wise.     These are all "old" injectors....I have spare "new" injector, but gather that the wear rate on the new injectors is higher.

Regards

Steven

[ABenzTek]

I've had good success bringing marginal (and terrible) MFI injectors back to life with deep cleaning and running a mixture of chemicals through them in my pop tester. Not sure what environmental harm I'm creating by the concoction, nor am I sure what about the mixture seems to be working, but it's doing a good job and 5 terrible injectors out the 6 I just recently tested are going to be "like new" according to pop pressures and spray patterns. If anyone wants their's done $40 flat rate, I could potentially save you a couple hundred of the greenbacks $$. That covers my time, shipping back to you, paypal fees, my chemicals, etc. Atleast you'll know which injectors are just not serviceable anymore!

[vande17941]

My injectors sucked...wrong opening pressure, leaked, spray pattern poor. I used one of those hydraulic pumps the Merc guys use on the diesel injectors (borrowed from my mechanic). Ran B-12 Chem too through them for about 5-10 min each and everyone of them cleaned up perfectly in all departments....opening pressure, pressure holding and spray patter....whole process was 1.5 hrs including removing and reinstalling the injectors