Pop Testing Rebuilt Injectors
 

I have 1982 300SD sticker on door says 9/81
Car had 175 k on it when I bought it . it now has 185K .... I did the diesel purge, replaced all filters, adjusted the valves, checked timing chain. rack bolt is new fixed the vacum leak's under the hood, compression check was good @ 315 ...got good shifting etc. did the brakes shocks etc. etc. I decided to put in new injectors after reading in the forums here.. I bought Monark Injectors did as directed in the videos & forums etc. Pop testing does not come out as in the video!! I got them to pop within 10#'s of each other but .....that took a long time .... they only pop once @1950 then pop at less then that... all 5 the same way an spray pattern does like a garden hose after that .. .. ??? car ran ok but the idle was CRAP !!! it was not to good before the new injectors either ... shook awful @ an idle when warmed up. re-set the rack bolt more then a dozen times even pulling over on the interstate in safe place.. over an over no change... any Ideas ??

Thanks Kin'

Howdy,

I rebuild injectors on the side.

Try these ideas, but my guess is that you already did.

1. Take one apart, clean with compressed air ;
2. Re-assemble. Make sure that the "rivet" looking part is in correctly.

Torque correctly. 59 ft pounds. (I think from memory).

It happens once in a while. Don't fret

Handle one Injector at time and do not interchange any of the Nozzle Parts with other Nozzles.

Also if you take long strokes on the Handle of the Nozzle/Pop Tester the Nozzles are going to hose out the Fuel.

pop testing
 

well I used the same motion on both types of injectors the Bosh go pop pop pop pop the Monarks hose out after one pop ... is this because of the brand of injector or type of ???

I am very familiar with injector testing. And I am very unclear as to what you are describing. If what you are describing is streaming, something is wrong. There should be no appreciable difference in the basic performance of different nozzle brands.

pop testing injectors
 

Ok this video shows pop testing of injectors the Monarchs do NOT DO THIS !! they pop 1 time then Hose out or stream or ?? this is not right an I got 2 sets the same thing ??????????? so is it the injectors ??? oh another thing the very tip of the when i pulled it to inspect the tip it has a flat spot on the side of every tip I checked ??? a the very end... for spray pattern??

video >>> vincewaldon.com - HOW-TO: Rebuild Diesel IDI Injectors
its at the end of the article ...

I don't know what to say.

The test depicted in the video is the chatter test. Not the same as the pop test. The chatter test uses a slow stroke; pressure is not a criteria. (Gauge valve is closed.) For the pop test, build pressure rapidly (gauge valve open) and note the pressure when the injector fires. One test per stroke. To test spray pattern, use a long stroke with the gauge valve closed.

Most injectors will stream if you build pressure slowly enough.

Did you buy new injectors or did you buy new nozzles?

pop testing injectors
 

I bought new nozzles, car is back together an running much better
thanks all ... Kin'

Hi folks,

I have just rebuilt a set of six injectors with genuine Bosch replacements.

Re-shimmed to get correct pop pressure, spray pattern good too but no chatter?

Is this something that's essential or perhaps not on all injectors.

Injectors are for OM606.910 non turbo

TIA

Hello folks, please ignore the above - the chatter required a lot less pressure than I applied via the tester.

I think the old injectors were worn achieving chatter at higher pressures.

One thing I have noticed is the soft residue on the springs. Using a high mixture of citrus orange with ultra sonic cleaner it fails to dislodge.

maybe something to look out for.

Was this Car run with some sort of Alternative Fuel other than Biodiesel in the past?

Also the part of the Injector you describe is exposed to the Fuel that is going to go back to the Fuel Tank. That means any Crud on the Spring is not going to get into the Injector Nozzle and I think it is extremely unlikely to plug up one of the Return Nipples on the Injector.

Where I used to work back in the 1970s I used to reject Injector Nozzles that did not chatter.
That resulted in Bosch sendeing us a notice their Nozzles do not have to chatter as long as they go up to the Pop Pressure and open suddenly with a good spray pattern and don't dribble more than X amount of drops per X amount of time during the pressure test (it ws 200 pis below the opening pressure held there to see if they dribble).

Hello Diesel and thanks for your reply.

The car had clocked up 126k of miles driving mainly around Oxford/Stroud area. I have rebuilt the top half of the engine which showed terrible signs of coking, this could/may have been attributed to the alt dome sensor issue - posted details here http://www.peachparts.com/shopforum/diesel-discussion/69422-om603-alda-removal-instructions-7.html

Greazzer gave me great deal of help cleaning using ultrasonic and citrus together with shimming (thanks bud).

Ultrasonic seems to prefer hard deposits which work well, this was really soft and lots of it blocking the whole internal core of the spring.

I have just had a reply this afternoon from someone breaking a OM606 with alt sensor and manifold butterfly, so should be good to go this week engine wise.

For the record I found pop testing quite difficult as the reading seem to vary even using the same injector.

That said, managed to persevere and get to within .5bar at the upper end of the MB spec - nearer 116 than 115 to allow for bedding in.

Cheers,

My w210 has just started to make the tell tale signs of worn injectors with 127k.

I noticed the S124 (see above) nozzles went at about 126k from memory, is this about the longevity of genuine Bosch nozzles?

S124 is '96 vintage while W210 is a spring chicken at '98.

btw, those Indian sourced nozzles (so far) have been okay, engine runs sweet as a nut.;)

I am late answering this.

Out of 25 Monark Nozzles I had one that was just OK and one bad. But, that was a long time ago in 2008.

Inbtween that time Monark did have some quality issues and there was like a Year were Monark Nozzles were not available till I guess they fixed the issue. That was over 3 years ago.

After 26K on the Rebuilt Monaks in My Mercedes I pulled them and pop test them and they were all excellent and even the pop pressures were still right on.

If you have assembled the Injector correctly and the pop pressure is at least close to what it is supposed to be any new Nozzle should not hose or pee out.

Even with a good Nozzle if the pop pressure is too low it will hose.

If you have bad Nozzles they need to go back to the Seller for exchange.