Injectors Testing

[Pawel66]

I have set up my injector tester and used a new injector to try it.

On a correctly working injector: do you get a spray that is a really nice and even cone of spray? Mine, on the new injector, is not that even, it sprays visibly more on one side.

Maybe it is a quewstion of the viscosity of the liquid I use - it is a gasoline fuel system cleaner, I was a bit afraid to work with gasoline itself... What do you use for injectors testing?

The injector opens at 275 PSi, but again, the spray patter is not what I read on the Forum in descriptions.

I certainly know this: https://www.sl113.org/forums/index.php?topic=1193.msg5880#msg5880

It is just strange that the new injector opens at 275PSI and has the wrong spray pattern...

[mrfatboy]

Pawel,

I use Seafoam to clean and test my injectors. I think I used kerosene once.  I get the cone shape pattern. Do all of your injectots have the same spray pattern?

https://www.amazon.com/Sea-Foam-Extreme-SF-16-Seafoam/dp/B0002JN2EU/ref=asc_df_B0002JN2EU/?tag=hyprod-20&linkCode=df0&hvadid=242667734520&hvpos=1o3&hvnetw=g&hvrand=3888548794506197680&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9031312&hvtargid=pla-406644540695&psc=1

[WRe]

Hi Pawel,
it's no surprise for me that even new parts don't work properly even there is a well-known name on it.
Maybe you should try to clean it. Do you know this video: https://youtu.be/Fb3fHKiVF4o?
Don't worry it's Christmas!
... Wolfgang

[PeterPortugal]

Pawel,

I too recommend looking at the Kent Bergsma videos.

Also knowledgable people also seem to put some emphasis on the noise. I think Kent calls it "chirping"...like a bird singing.

You know it when you hear it !

Regards

Peter

[Pawel66]

mrfatboy,

I have just tested the first one, a spare I had on the shelf. A new one from MB. I am scared to think what those removed from engine would look like.... Thank you for chemicals suggestion.

Wolfgang,

Thank you. I am negotiating with my wife the use of her ultrasonic cleaner... yes, I have seen thois Kent's video, but I will refresh it now as I got to the topic. I know he is selling cleaning mixtures, it is just difficult shipment from his place.

The colours of the spark plugs differ from cylinder to cylinder in my car. The biggest is between 1 and 4. Injectors are suspects here. They are all new, but now I see that it may not matter, actually...

Merry Christmas!

[Pawel66]

Peter,

Thank you! They are chirping nicely, but spraying badly and in the wrong time . I will remove the ones I have in the manifold, see what i get...

[doitwright]

Kent Bergsma has another video on back flushing the MFI fuel injectors where he cuts one apart so you can see the inner workings of the injector. To back flush it will be necessary to pry open the spring loaded tip of the injector.

[Pawel66]

Frank, yes, thank you I have just watched again 4 or 5 videos from Kent on this topic. A lot of good materials. I destroyed one old injector when I was trying to pry up the cone a bit - it just went lose. One has to be very careful doing that....

[PeterPortugal]

Pawel,
Good luck and Happy Christmas to you !
Peter

[doitwright]

I would only attempt to pry the injector tip open with a plastic tool. If you score the tip under the spring loaded cap, it will leak gas.

[mrfatboy]

DoitWright is 100% correct.  It's very easy to damage the pinal. I used plastic toothpicks to wedge open the pinal slightly and soaked the injectors awhile.  Results varied.

Even if you get some stuck particulate removed it might have already corroded the pinal with micro pitting causing bad/leaky spray pattern.

I was told by Hans (Hans injection pump rebuilding ) 20 years ago that the R2 versions of these injectors are very difficult to clean if at all.  He said its best to buy new ones.  The R1 versions are very easily cleaned.

[Pawel66]

I did not even get a chance to experience the spray pattern from the injector I attampted to clean - it just popped open and, probably, got detached from the spring that holds it tight.

I was thinking of cutting something like V-shaped slot in thin but stiff plastic sheet. Credit card would be too thick, but maybe shirt collar inserts... But now I am afraid to mess around with it too much.

[Charles 230SL]

hi Pawel, I ordered Kent Bergsma's MFI Tester/Cleaning Kit several years ago and seems it (the kit) included a brass tool with a "V"cut out at one end. Purpose of the "V" cut-out was to clean the injector valve and valve seat. The soft brass prevented damage to the valve and seat.   

[Pawel66]

Charles, thank you for pointing that!

My issue with items from Kent (other than some video materials I bought from him for some of the W463 and W113 repairs) is that when you add shipment, duties and tax - you are +100% of the price. So, e.g. I bought locally a tester for diesel injectors (plenty of them around for $70-80) and I just replaced the gauge.

But the tool you mentioned may be a different story - maybe he will sell it separately, given I am on the othe side of the big water. I will write a request.

[Pawel66]

I went to look at the products and videos we talked about. I think I will experiment a bit more with what to use to raise the cone-like valve and keep it open while backflushing. A tip of a very thin loom tie may be a candidate here.

Not sure if I can spot on the pictures the bronze tool Charles mentioned...

[Charles 230SL]

But the tool you mentioned may be a different story - maybe he will sell it separately, given I am on the othe side of the big water. I will write a request.

Pawel, the brass "tool" is quite crude actually and appears to have been fabricated locally in Kent's shop. I haven't used it in a few years but I'll look through my old parts bin and find it. If you don't get a favorable response from Kent, just PM your address and I'll send mine over to you.

Incidentally, after unsuccessfully attempting to clean my old injectors and get satisfactory "chirps" and spray patterns, I gave up and ordered six new ones. The new ones were Bosch R2's and out of curiosity, I used the MFI tester I got from Kent to check the new injectors' opening pressure and spray pattern. Ironically I didn't get very consistent spray patterns and the release pressure varied among them (and these were new!). I attributed the inconsistent release pressure(s) and spray patterns to the accuracy of the gauge on the tester and the viscosity of the cleaning fluid I used (Liqui Moly Diesel Injector Cleaner). 

[Pawel66]

Charles, thank you for your kind attention!

Maybe if you could send a picture of this tool, I would know what to ask for, that would be a great help.

As for the new injectors calibration (pressures and spray patterns), as I wrote, I tried only one new I had at hand and it was a fail, actually. Could be the viscosity, could be the quality control at Bosch in whatever place they produce them... With given viscosity of the liquid you use, youe would have expected, perhaps, a similar deviation, if any, across the injectors, rather than a random pattern.

Waiting for all the Christmas dinners and visits to go away, to get back to garage, where I was hiding last couple of days when the house was being made tidy...

Merry Christmas!

[Pawel66]

Enclosed is what you see at Mercedessource as for the tools for MFI injectors back flush (or cleaning and testing overall). I cannot spot anything brass you could use to open the injector and keep it open during back flush. In the video Kent mentions plastic pieces used for that. Not sure what this piece of wire is used for. The tiny pieces in the plastic bag may be the ones used for keeping the injector open.

[Charles 230SL]

hello Pawel, I've circled (in red) the brass tool that was included in the kit, but I'm not so sure it was meant for back flushing.  I just went through my old parts bin in the basement and didn't find the tool,,so I'll go through my garage drawers.  I tend to stash things in certain places to ensure I can find them again at a later date. unfortunately I end up forgetting where they were stashed. I'll keep looking, meanwhile have a Merry Christmas!

[Charles 230SL]

Pawel, I found it and attached some pictures. Really not much to it - just soft brass tubing with a notch cut-out at the ends.
I'm sure MercedesSource fabricated it in their shop.

[Pawel66]

Thank you again!

You are not alone in storing parts and tools in logical places to find them accidentally years later having bought the new ones in the meantime....

I think this tubing is to lever up gently the cone to insert the plastic triangle piece to hold it up.

Square tube - as you get flat surface down below. Thank you again, I think I will just fabricate something like that.

Great help!

[kampala]

When I cleaned the injectors, I was able to use my fingernail (yes still attached to my finger) to pull on the cone and slip in a very thin piece of plastic like a small zip tie tip.  Then using carb cleaner was able to clean the seat and cone while using the zip point as the cleaning brush.  Did not check spray pattern but car ran nicer for sure. 

[Pawel66]

Thank you, my thinking was very similar. I will just add a back flush to it...

[doitwright]

Based on the photo of the brass tool, it appears to be a brass square tube with the end cut on an angle. Probably could achieve similar results with the plastic trim tools used by car radio installers. Maybe even a plastic straw.

[Pawel66]

Thank you doitwright. I will experiment with some materials and report back, I have a couple of ideas.