rebuild injectors/bad spray pattern - page 1 - Troubleshooting - VWDiesel.net The IDI, TDI, and mTDI source.

• rebuild injectors/bad spray pattern by arnold on 19 Oct, 2010 09:05
• Hi,
  
  My injectors needed a rebuild so i order'd a set new genuine bosch nozzles,did the cleaning and preparing of the inside as described by vince waldons site,then had them calibrated at 155 bar.
  
  Mechanic said the spray pattern was not so good,they actually had a very small 'piss' when they open
  
  Now these come from a very thrusted e-bay seller,and in a plastic sealed bosch box so it's hard to believe i got counterfeit/china nozzles
  
  Do these things need a break in ?Should i just run them and tested again in a few weeks  ?
  
  http://cgi.benl.ebay.be/ws/eBayISAPI.dll?ViewItem&item=120607324726&ssPageName=STRK:MEWNX:IT
• #1 by Vincent Waldon on 19 Oct, 2010 09:29
• I've occasionally seen brand new OEM nozzles that have uneven spray patterns...  I've always been able to get 'em to work by disassembling the needle assembly (wearing gloves... the finish is evidently susceptible to fingerprint oil!) and flushing with brake cleaner and then clean diesel.  The theory in my head is that the machine oil gets a bit gooey in storage... but it's just a theory.  
  
  I read that "they do settle in" and conversely "they absolutely do not settle in"... given the tolerances etc it makes sense to me that they will settle in a bit, and there's lots of anecdotal evidence on the interwebs to suggest that they get quieter over the first few thousand miles.
  
  I guess it comes down to safety... if your mechanic thinks there's a defined stream when they open that's a potential cutting torch... if it's just a very distinct part of the spray I might be inclined to run 'em as is for a couple hundred miles and then have 'em inspected.
  
  Or... since you already know how to do the work... disassemble, clean and lube the needle... and then get your mechanic to quickly pop-test 'em again for spray pattern.  As long as you keep all the same parts together there should be no appreciable change in breaking pressure.
• #2 by Vincent Waldon on 19 Oct, 2010 13:16
• True dat.
  
  I have a very calibrated "Grrrrrrrrrrrr" that's different from the "aaaahhhhhhhhhh".   
  
• #3 by arnold on 19 Oct, 2010 14:16
• It's not a stream,he said they sprayed fine but with a few thin beams in it,maybe like vince said some gummed up oil from storage.
  
  I was curious so put them in the engine,first startup it blowed a huge white cloud,air in the injectors i guess but after a 15 minute drive it still smoke's white.
  No more black smoke however so thats finally solved.
  The first 10 min the injectors all made a LOUD mettallic ticking sound,after the drive the sound is quieter so i have faith in them.
  
  
  I will run them for a few weeks and have them tested again
  
• #4 by Quantum TD on 20 Oct, 2010 00:15
• The pinging of the injectors never really goes away. It may get lighter, but it never goes away.
  
  The injectors may have been on a shelf for a long time, so maybe that is the problem (I dunno, I can't read whatever language that ebay listing is written in).
• #5 by 745 turbogreasel on 21 Oct, 2010 19:03
• I burned through a head into the water jacket in 30 minutes with a  bad spray pattern, but it was definitely running really bad.
• #6 by Toby on 21 Oct, 2010 23:27
• The reason the spray pattern was bad on the nozzles was because you have grit in them. You really need "clean room" clean to be safe when working on injectors. Just the dust falling out of the air in your living room is enough to louse them up. You also need an injector tester to do any work on an injector. If you don't have one you won't know when you have foreign material in the nozzles. With as clean a work area as I can manage, 1 out of every three or four I do need to come apart again to be flushed out. I would not use carb cleaner on a new nozzle. I like to use copious quantities of WD-40 to hose off everything as I assemble the injectors. I wear a clean hat since I have found that stuff falling out of your hair is a big source of injector problems. The best thing is for the absolutely clean housing, spring, seats, and shim to be sitting there ready to go and open the little plastic container the nozzle comes in, hose down the outside with WD and immediately drop it into the housing. Drop in the rest and screw it back together. The thing should not be open more than a few seconds.
  
  THEN pop test it and if its not right take it apart and hose it down again and start over.
  
  I have seen guys go backward in a big way when replacing nozzles. I have never seen a nozzle marked with a finger print, so I don't think the latex glove are for that. Its to keep the crap on your fingers out of the nozzles. I use my fingers all of the time and never see a mark or a problem.
  
  The pintle must also be a sliding fit in the nozzle, itself. If it sticks or catches anywhere you have a problem. Running injectors with a bum spray pattern from grit in the nozzle will ruin them in short order. If they are not right DO NOT RUN THEM. They will eat themselves in short order. They are not like a cut finger. They do not heal. They will eventually either grind up the grit or completely destroy themselves. Grinding up the grit also wastes the pintle/nozzle fit and pre wears out your new injectors.
  
  Upping the break pressure doesn't do anything except change your injector timing since they pop later at the higher breaking pressure. Not a big deal if you are road testing incramental IP timing changes and picking the best setting, but the stock setting won't be correct after you up the pop pressure.
• #7 by arnold on 23 Oct, 2010 07:33
• These injectors are absolutely clean,after lapping the surfaces i've left them soak in paint thinner for a few minutes,then blowed them clean with compressed air,soaked them again in fresh thinner overnight,blowed them dry again,opened the sealed new nozzle and dropped them in,lubed the inside with WD40 and assembled them.
  Never pulled the pintle out the nozzle,just moved them up and down a bit to be sure they moved freely.
  
  The mechanic who pop tested them cleaned them afterwards with an ultrasonic injector cleaner.
  Not driving the car daily couse i'm well aware of the damage they can do,i've found a cheap old injector tester so i can do it myself.
  
  Although slightly louder it runs very well,how does an engine with pissing injectors sound ?
  
  
• #8 by Smokey Eddy on 24 Oct, 2010 02:51
• Paint thinner will leave a residue will it not?
  I would motion towards something a little heftier. I used lacquer thinner with mine and other than that i've only ever heard of using brake cleaner.
  I don't like the way paint thinner doesn't clean my hands so i try to stay away from it...
  thats only one ... very naive guys opinion though.
  
  pretty sure it will sound the same amidst all the clatter. It would be silent damage i think.
  pitting in the piston face.
• #9 by arnold on 25 Oct, 2010 16:24
• It's cellulose thinner and...i dont know,but they were clean as a lab coat  
  Don't be so moddest smokey eddy,you opinion is greatly appreciated
  
  I've driven them a while now,when i wanted to pull them for inspection i found out i cracked the boss on 1 cilinder   (apperently it had a little crack before),never knew this so the head will be pulled and replaced with the ported aaz head i have.Time to wake this little engine up whoohoooo
  
  Injector testing will happen this week.i'll ask him if he can make a video of the spray pattern
  
   
   
• #10 by 2strokesmoke on 25 Oct, 2010 22:11
• I  installed 4 Bosch NA13X reman injectors in my 82 Caddy with 1.6 NA about 2 months ago.
  The first 100 miles they were noisey (especially the first 50 miles) after that they quited down.
  At first I was concearned,because they were so loud - all I could hear was injectors-not the engine LOL
  I just had the head off the engine this weekend,to replace a leaking head gasket (was due).
  injectors looked good,no evedince of poor spray-glow plugs and pistons all looked perfect.
  So I would assume they initial injector noise is normal?
  I though the info might help.
  Mike
• #11 by Toby on 25 Oct, 2010 23:41
• No, it is not normal. I have changed hundreds of nozzles and have never seen it. Or rather heard it. It is not likely the injectors that you are hearing but a rattle from the fact that the spray starts way to early due to the pintles hanging open a bit until the foreign material gets ground up and spit out.
  
  BTW, where do you guys get the idea that there is some big difference in the look of the glow plugs or piston tops with a poor spray pattern from an injector? An injector would have to be really hosed to lay down enough extra carbon to be noticeable.
• #12 by Toby on 26 Oct, 2010 10:56
• Slice the tip off of the injector? How is it going to do that? Answer: Its not. Some other problem caused that. LIKE ETHER! I have taken several motors apart with no remarkable changes, much less damage, to glow plugs or piston crowns, with injectors so bad that it was a solid low pressure stream. No spray involved. In fact none of these motors that came out of cars that I drove ran all that badly. Yeah, they smoked a bit and were a little hard to start, but still ran and drove pretty well.
  
  The only damaged glow plugs or injector tips that I have seen came from cars with a can of ether up by the wiper area under the hood. One shot of ether will take the tips off of a glow plug or two and I have broken the block on a good running car trying to get it started to get to work with a flat battery. Ran fine when I parked it the night before; burned a quart every 250 miles from them on. It got down to a quart every 50 miles within a week or so.
• #13 by R.O.R-2.0 on 26 Oct, 2010 17:19
• ive seen a 6.2 head that had been torched by a bad injector. had holes and erosion where they should NOT have been. pretty sure they pulled it because it ate into the water jacket or something.. and didnt have compression on that cylinder.. but that was a long time ago before i thought diesels were very cool..
• #14 by Toby on 27 Oct, 2010 18:50
• Quote from: libbybapa on 26 Oct, 2010 17:12

  When the fuel is not atomized, but rather a more solid stream, then the fuel to air ratio is extremely high near the center of the stream and results in extremely high combustion temps that are sometimes hot enough to cut glow plug tips or erode piston crowns, even slice into the aluminum head.  It is a well known occurrence that is also well documented by Bosch.
  

  
  It does not work that way. The highest temps are not in the richest portion of the stream. The highest temps are on the lean side. I suspect that these problems have much more to do with vast quantities of extra fuel injected into one hole when the pump is going bad. Remember that it is the oxygen that does the cutting with an A/O torch, not the acetylene.
  
  The problems with the 6.2 Detroit/Chevy diesels were caused by IP failures that caused vast imbalances in the fuel metered to each hole. The ones that got the extra fuel melted down. Just replacing the hard parts without doing the IP guaranteed a second failure.