VWDiesel.net The IDI, TDI, and mTDI source.
General Information => Troubleshooting => Topic started by: arnold on October 19, 2010, 09:05:39 am
-
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 (http://cgi.benl.ebay.be/ws/eBayISAPI.dll?ViewItem&item=120607324726&ssPageName=STRK:MEWNX:IT)
-
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.
-
True dat.
I have a very calibrated "Grrrrrrrrrrrr" that's different from the "aaaahhhhhhhhhh". ;D
-
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
-
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).
-
I burned through a head into the water jacket in 30 minutes with a bad spray pattern, but it was definitely running really bad.
-
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.
-
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 ?
-
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.
-
It's cellulose thinner and...i dont know,but they were clean as a lab coat ;D
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
-
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
-
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.
-
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.
-
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..
-
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.
-
EGTs get high for a number of reasons, not the least of which is unburned/still burning fuel getting dumped into the manifold(s), which is why we universally see higher EGTs with more fuel. As the mixture goes up so do the CC temps UNTIL there is more fuel than can be burned, at which time CC temps decrease due to incomplete combustion and evaporative cooling of the unburned fuel. A stream of fuel does not burn nearly as hot as a well atomized one. I am not saying single cylinder overtemps and attendant damage due not occur, merely that a poor spray pattern is not the cause.
I have seen lots of cars with pissing injectors and NO cutting torch action. It should be noted that diesels that get melted down always have pissing injectors, so I suspect that they are a symptom of a meltdown, not the cause.
-
My mechanic had some info from bosch,
shiney posters with pics of glow plugs in different states,
one burnt off,.. and a list of possible reasons included bad injectors.
I've seen an '85 Jetta TD with no either can and 4 burnt-off injectors.
I've seen an engine that I know the owner used either on,.. and the glow plugs didn't work,.. but weren't burnt and the engine runs great.
He swore the trick was to just use a very small squirt.
-
Cool, so if someone has dangerously high EGTs, they can save their engine from meltdown by just turning their fuel up more and getting that evaporative cooling effect. I never knew that before. On a similar note, I've also heard that you can port and polish your engine by pouring sand in the intake while it's running.
The EGTs won't go down by adding more fuel because that excess fuel is burning in the manifolds. The CC temps are lower when vastly overfueled because combustion is incomplete. When compared to when it is properly fueled.
If these engines are significantly over-fueled they don't run cooler, they melt with the piston crown flowing down past the rings in a most disturbing way. Complete engine meltdown happens before a stoich mixture is achieved.
(http://i13.photobucket.com/albums/a269/libbybapa/a417.jpg)
I am not saying that motors don't melt down. Just that a pissing injector is not the cause.
Not too many years ago it was typical to see semis out on the great plains running what they called the "intermountain pump" trailing huge amounts of black smoke as they went by at 90+ and when climbing the foothills of the Rockies. At night you could see flames licking out of the exhaust stacks. Hence the words to the truckers song "13 days". "My rigs a little old, but that don't means she's slow, I got fire out the stacks and she's blowing black as coal"
Clearly these trucks were running way past stoich and did not melt down, so a pissing injector in a Rabbit diesel isn't going to do it. I suspect that what does it is too much fuel AND too much timing. It has been known for decades that max power comes with excess fuel and LATE timing. Talk to the guys building the 1200 hp big cam Cummins motors that they run in the semis and the guys racing the semis on circle tracks, or the Les Schwab semi stunt team.
I suspect that the max hp diesels are not very snappy, if my experience with automotive diesels is any indication. I for one would be happy to give up some top end hp for much better mid range performance. 100 mph in a N/A Rabbit diesel is all that I need. The best thing about my 5000TD is the oustanding mid range torque. That comes from lot of timing in early. It does, I suspect, limit how much fuel I can put into it. I would not trade any of that for another 20 mph on the top end.
-
Toby since injectors for you are not a maintenance item...
When I need new injectors then can you buy some and send them to me. I'll send you my old ones for the new ones. I will pay shipping both ways of course. ;)
-
Toby since injectors for you are not a maintenance item...
When I need new injectors then can you buy some and send them to me. I'll send you my old ones for the new ones. I will pay shipping both ways of course. ;)
I never said that injectors are not maintenance items. Far from it. I haven't owned an injector tester for 25 years, nor have I changed hundreds of nozzles because I think it is not important. I am just trying to dispel some magical thinking ans mountain medicine. Perhaps if you guys have some Bosch info indicating that I am wrong you could scan and post it or point me to a Bosch site that backs up what you are saying. I suspect that it is a myth retold so many times that it is taken for the truth without question.
-
FWIW, if the excess fuel is burning in the manifolds, then you are still not above stoich.
Stoich does not mean that no oxygen remains in the exhaust. It means that the ratio of fuel to air allows for complete combustion of the fuel w/o excess air. When the mixture gets above stoich combustion is not as complete as it is below (in a diesel) and excess fuel and unconsumed oxygen both end up going out the stack.
Pardon me if I trust Bosch and the experiences of others who have had it happen to them more than I trust you about this. ;) I'm done with this discussion. I hope you don't mislead too many people.
As I said before, point me to some Bosch literature that tells me that I am wrong and then I will believe the conventional wisdom. So far 25 years worth of experience does not support your contention. So educate me.
-
Toby since injectors for you are not a maintenance item...
When I need new injectors then can you buy some and send them to me. I'll send you my old ones for the new ones. I will pay shipping both ways of course. ;)
I never said that injectors are not maintenance items. Far from it. I haven't owned an injector tester for 25 years, nor have I changed hundreds of nozzles because I think it is not important. I am just trying to dispel some magical thinking ans mountain medicine. Perhaps if you guys have some Bosch info indicating that I am wrong you could scan and post it or point me to a Bosch site that backs up what you are saying. I suspect that it is a myth retold so many times that it is taken for the truth without question.
If bad spray/worn nozzles aren't maintenance on an injector the only other thing could be breaking pressure, right? Offer is still on the table, I send you my old ones and all you will have to do is make sure the opening is correct. I will take the new with shipping of course.
-
fire is hot. it melts pistons, and glow plugs.. and a stream of diesel makes a pretty skinny, hot fire..
-
You are forgetting a number of things:
1) Un or poorly atomized fuel does not burn well nor very hot. (read that "pissing injectors")
2) In an IDI diesel the injector stream first hits the wall of the precombustion chamber, swirls around, burning as an overly rich mixture and then exits the PC chamber to complete its burn in the main CC. Nowhere does a stream of fuel ever hit the piston.
3) The glow plug is not in the center of the injector spray pattern. The stream needs to be off center a bit to hit the glow plug and most pissing injectors that I have seen shoot pretty much straight. Not all, but almost all that I have seen. Ether on the other hand will take the end off of a glow plug in a heart beat if it gets into the PC chamber, as will being a bit too heavy on your glow plug switch or an erratic glow plug controller.
Also please note that I am not saying that a bad spray pattern won't damage your engine. Just that it won't create a cutting torch effect. It will wash down the cylinder walls and dilute your lube oil as well as carbon up the inside of the engine.
-
Toby, you are so close to truly understanding diesels
yet you cling to ideals that are based in the gasser world
first off "Stoich"
haha, a diesel NEVER runs Stoich. It may briefly touch it for a second, but moves around it like a dancer on the floor
and yes streams burn holes man. This ain't no Chevette, when fuel goes in to that pressure it does burn and streams, burn late and hot!
On direct injection Deere's if you got a straight shot out a bad injector (piss line)
10 times out of 10, you got a hole right below it in the piston. Ask me how I know (JD Master Tech)
And the reason the sled draggers inject late is the amount that they do inject, later in the injection delivery the more heat in the cylinder (DIRECT INJECTION ONLY) and they need all the heat to light the pail of fuel they throw in. In fact, you gotta disregard everything about those guys. Tuning a street diesel like they do is like runnin NITRO METHANE in your I'm assuming CHevy MAlibu.
Don't piss off these guys, the collection of knowledge on this site is astounding, and no one wants your piss in this pool
-
loooool...
so many people assume gassers and diesels operate under the same principals.. but not even close..
diesels are a different breed. the only thing they share with a gasser, is the fact that they are a piston engine, but other than that, not much in common..
"no one wants your piss in this pool"
that was awesome, i must say..
im going to remember that quote for sure..
-
THREADJACK AHEAD!
Anyone remember that swimming pool scene in Caddyshack?
END OF THREADJACK............ ;D
-
Screw Caddyshack
Best old school movie was 'The Great Outdoors'
With my favortie dude John Candy, another great Canadian!