Fuel injectors o-rings

Hi, I'm preparing to replace the fuel injectors of my 124, 230E 92, 102.982 engine. I bought the parts from the local MB dealership, and they sell me the injectors and a black rubber seal (they called it "guide") that is mounted at the bottom long rod of each injector, to seal them with the cylinder head. The dealerīs attendant said that there is no other part involved in this job.
Well, it is the official MB dealer here, so I would have to believe them. However, searching this NG and the web I've realized that there is another o-ring/seal that I could be missing, one that seals the injector with the fuel rail on the rear upper end of the injector. I'm doing this replacement to solve a slight hard warm starting issue, and to improve a sometimes vibrating idle, therefore it is important not to leave any air leaks. Is the dealer right? Thanks MMansilla
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Yes, the dealer is right. That is the only thing that adapts the injectors. The injectors are the fixed wit a bracket for each two cylinders.
The seals must have the right softness (will harden with age) to ensure tight fit.
But do you really need to replace all injectors ? (well, you will of course then have a good feeling that all is OK)
They can be tested whether they open at a certain pressure difference, that the remain closed below that threshold and that they provide the right spray pattern above the threshold.
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I appreciate your answer Jens. Now I'm ready to undertake the injectors replacement. Do I really need it?. Well, I' donīt know for sure. I would have carried out the test you mention to know (wasn't aware of it). As you insinuate, mesurements are the only way to proper diagnosis. In addition, the carīs engine (with 90 kmiles), is in general fine, the warm start and idle problems are just marginals. However, at this point with the injector already bought, I have no choice but to change them all. They were relatively cheap, only US$100 for the parts, compared to ultrasonic cleaning for $75 (seal replacements included in this one). So, cost wasn't a concern. My main concern is, though: the job seems easy enough, but I'm unexperienced, and in such a case the saying "the enemy of good is better" becomes more meaningful (maybe this is the point that lies behind your question). I really like the car, so I hope to do a good job. Thatīs why I was asking about the seals/o-rings. Thank you.
MMansilla

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