Leaking Injectors - Any fixes?
 

Hi,

Is there any way to fix leaking injectors (petrol) without replacing the whole lot?

Replacing the seals? Cleaning them?

Cheers,
DK

Try running a tank or two of Techron Injector Cleaner and see if that helps. Otherwise, you can replace only the offending injector instead of the whole lot. Have you actually verified the leaking? How? What are the symptoms you're trying to cure?

Gary

I was always told that those injector cleaners never did any good :confused:

The car (1991 500SL) stutters every once in a while and I've been told that it is most likely leaky injectors.

Is the only way to tell if that is the problem is to take the head off and see where fuel is leaking out from?

Cheers,
DK

There are a number of mail order places where you can send injectors for cleaning. They bench test, clean (including a reverse flush), flow balance, and send them back for roughly $25 per injector. If interested, try an internet search.

Don't take the head off to check the injectors. The injectors can be pulled individually and tested in a benchtop rig.

The injector seals are between the injector and the head. Poor seals here would cause an air leak, not a fuel leak.

Cheers,

Found this place and it looks good.

http://www.cruzinperformance.com/fuelinj.html

I was under the impression that the injectors were not serviceable? But a bench test will tell which ones need replacing wont they, rather than replacing all 8!

I'm impressed at how well injectors are designed and they seem to never wear out. Just keep them clean and they last forever.

That link is the cheapest I've seen for injector service. Some people, including myself, have been able to clean them at home. This involves an ultrasonic bath cleaner, appropriate solvent, a way to reverse flush the injector, and a power source to open the injector pintle. Caution, do not use 12v as that may fry the injector. They don't operate at 12v. The pintle opens at aroud 1.5V.

Though the DIY method may clean the injectors, I'm not sophisticated enough to flow test them. That's where this mail order cleaning service is better.

I wonder if a Motorvac treatment helps.

Your symptoms (intermittent stuttering) may or may not have anything to do with the injectors. Do a search on "rough idle", "missing at idle" or something similar and you'll find some other possible causes. Do a "Search Title Only" search on the word "injector" and you'll find all kinds of DIY info, some good, some not. Use discretion.

It seems kind of pointless to spend $15 - $20 on having your injectors cleaned when you can buy brand new ones for $25.41 ea. from FastLane. If you're going to go to the trouble of pulling them out but don't want to spend the $$ to replace them all, have them tested only and simply replace the bad ones. Be sure to replace the seals on all of them, though. They're only $1.36 ea.

Gary

Good call, Gary. You're right about the price. They're $135 for my car, and at least $50 for most American cars. Looks like another good design idea by MB on the 500 engine.

Those injectors on M119 engines cost more than 200$ for a single piece.

I actually have had the same problem. One of the injector was leaking petrol onto the engine block causing blakening marks etc. I was kind of worried for fire troubles more than anything as it did not cause any harm to the drivability.

My mechanics told me to leave it. (it was an early W140 and replacing 1 injector requires unpluging all of them which could cause damage to the plastic of a good injector thus requiring more replacement)

The folks here told me to leave it and buy a fire extingisher.

I went ahead with the replacement and lucky for me, my mechanic did not break any and I only had to replace that 1 injector. Cost 200 USD each!!!

NOW, I don't have a leaking injector that leaks petrol onto the engine block. BUT I have hard to start problem at warm temperature. I search, replace, search and more search, I still have to start the car twice in hot/warm engine!

My advice, its your call. Its best to leave it unless you really have to fix it!

Thanks Guys,

Though I would post an update incase anyone does a search for this topic and wants to know what I found.

I spoke to some people that test/clean injectors and they basically told me with these mechanical injectors (thin metal ones) that run on the KE injection system, it is not worth trying to fix them as they use a high fuel pressure, rather than electrical current to open them, and once they go they are not serviceable.

However since my motor has only done 50,000kms (1991 R129) then they would test them to see which was leaking so I could just replace that one. Hopefully the others will be alright as they should have a few miles in them yet.

What is the end result? Have you solve the problem?