Genuine Bosch rebuilt injectors – Poor Quality?

[RunningTooHot]

Never assume anything...

I recently diagnosed my hard-to-start problem as a loss of pressure (fuel bleed down) in the injector lines. Since my injectors are less than three months old, I assumed that the problem was elsewhere. I subsequently replaced the brass o-rings underneath the delivery valves in the injection pump to eliminate potential leakage at that source. The engine idles _ever_so_slightly_ better, so apparently there was some leakage in one or more of the o-ring seals, yet the starting problem was not resolved.

When I pulled the injectors out to check the engine compression, it turns out that two of the injectors leaked so badly that I could see that the ball pins in the pre-chambers were wet with fuel. One of the other injectors has a small amount of external seepage as well. This points to some serious quality control issues. Three injectors out of five are bad – that’s ridiculous. I'm curious what other people's experiences have been with genuine Bosch brand rebuilt injectors.

I would like to know if anyone else has experienced these quality control problems, or conversely, please chime in if you have had success in using them. I'd like to get a feel for whether this was just an isolated case of someone having a bad day at the factory or if there is a consistent problem. I'm a little gunshy at this point about having blind faith and just installing a new set of injectors. If it turns out the other people have had these problems, I'll obtain the new set under warranty and send them to a diesel service shop to have them pressure checked before installing them -- however I don't want to go through this extra expense if it's unnecessary.

I appreciate anyone's replies to this inquiry. Thanks in advance!

RTH

[ricali]

A few years ago we had a Bosch facility right down the road from here in mass.. Well I knew some of the bozo's that worked there yes I said bozo's. you can just quess why the plant isn't here anymore. Haven't bought any bosch parts until last week. I recieved a bosch oil filter made in India. nuff said just my .02

[MarkM]

I cant offer much beyond my own experience...I bought five bosch rebuilt injectors 2 or 3 years ago from mail order MBZ parts place. Before putting them in, I brought them to a reputable MBZ shop (Hatch & Sons, Wayland, Mass.) and had them checked for spray pattern and release pressure. They were all within spec, and have performed very well. The guys at Hatch and sons recommended that I check them...they said that they always do, and have had Bosch factory rebuilt injectors test way out of spec and need to be returned.

[RunningTooHot]

Thanks for the information everyone. I guess that I’ll get the 5 injectors due to me under warranty, plus I’ll buy five more, then take them all down to get tested. Hopefully, I can get a 50% success rate (?!) and return the other ones. I hate to do that to the supplier, but if they are providing defective parts, I guess I shouldn’t feel too guilty about returning the others.

RHT

I get really PO'd at this type of stuff. Tonight I installed a flousecent light fixture for a friend. It was faulty. She ran to the home center before closing and got another . I installed it and it too was faulty. Seeing as these items were on closeout I determined the store to know these fixtures were bad and trying to dump them at the expense of my time and labor. There are budget and tax differentials for the store as too returned goods. I do not appreciate being used in this manner. As a comsumer I am doing the footwork for them to legally flip bad the inventory into a different column.

Bosch seems to be in this mode. Hiring substandard and cheap labor, selling an estimated quantity of unacceptable parts. The returned parts can be juggled and postponed per quarter to make the bottom line look better at the next meeting. Thus pay raises, premotions and bonuses for the crooks who perpetuate this practice.

Personnaly I think the companies should be legally obligated to pay for your time per percentage of faulty units sold. Unfortunatly our colleges, corporations and legislature are devising ways to make a fast buck rather than a steady buck.

[drawde]

How do you go about getting your injectors checked for spray pattern and release pressure? I have an 85 300D with 185,000 miles. Do you take them out (what size wrench do you need?) Should I bring them to a dealer? How long does it take and how much should it cost? confused:
Thanks:

[RunningTooHot]

Drawde:

There are shops that specialize in rebuilding/repairing diesel pumps & injectors. Their clientele is primarily comprised of big rig repair shops. Try looking in the Yellow Pages, or call a local truck repair facility.

RTH

[skalie]

The local shop I use tests your injectors for free. It's not a big thing for them having all the right tools and all.

As for the removing injectors, I think it's a 17 to do the lines and the injectors themselves are a 27, could be wrong.

I used to use a pipe wrench, although I think a 27 socket can also get them.

RTH,

Getting ahold of bad injectors is frustrating. I was a diesel mech of over 20 yrs and one of the places I worked had a fuel shop in-house (authorized Bosch rebuild). Of the ten or so guys working in the fuel shop, there were only one or two that we (in the engine shop) could depend on. BTW, the fuel shop guys only made approx 75% of the engine shop guys, plus they got to work inside in air conditioning, no weekends, etc.

Anyway, one of the best troubleshooting tools for a diesel is a infrared heat gun. You can pick them up for about $85.00 and for diesel work, especially marine diesel work, they're worth their weight in gold.

The three areas of concern on your nozzles are - spray pattern, lifting pressure, and holding pressure. Generically, in order for fuel to reach the combustion chamber, it has to develop enough pressure to lift the spring holding the flat check valve just prior to the pintle nozzle. If you're leaking fuel past the flat check valve at night, then either the flat check valve is leaking and/or the spring pressure is weak. Both of those problems, along with poor atomization, will show up when the engine is running by using the heat gun on each exhaust riser. A well tuned diesel should have no more than 75 degrees difference between the cylinders. Obviously if your injectors are real bad the engine will stumble and run rough, in which case it's easy to disable each injector by loosening each fuel line - similar to pulling each plug wire on a gas car to isolate the troubled cylinder.

If youre concerned that maybe the injection pump is the culprit, then just swap injectors and see if the problem follows the injectors. Keep in mind, that over 90% of fuel injection pumps sent to the fuel shop did not have anything wrong with them. Of course, they rebuilt them anyway at a tune of 300-800 dollars. Usually, it's only the delivery valves or manual priming pumps that go bad on the injection pumps, assuming of course that they havent run dry and have had clean fuel in them.

Sorry for rambling, gotta get back to work. Good luck.

Jeff

[skalie]

Originally posted by Boatguy789
Sorry for rambling.....

Jeff

Apology not accepted, your sharing of knowledge is deeply appreciated.

[RunningTooHot]

I actually have an infrared thermometer…it is quite handy for many purposes. Unfortunately, on the MB 617 turbodiesel engines, it is not really possible to get a good reading at each exhaust runner due to it’s configuration. The exhaust ports pretty much dump into a log type of manifold, with very short primary tubes (if you can even _call_ them tubes) and they look to be siamesed on cylinders 2&3 and 4&5.

Two of these *wonderful* rebuilt Bosch injectors are leaking past the disc valve so badly that the fuel lines lose pressure in a matter of a few minutes! The ball pin in the prechamber is wet when I remove the injectors. It is hard to imagine the idiots in the rebuild facility could screw things up this badly. The reason that I decided to go with genuine Botch, er… Bosch rebuilds is that they (supposedly) use new tips on all of them – they do not re-grind them. How could they possibly screw them up? (asked rhetorically, of course; as they did find a way to do so!)

Thanks Again Everyone!

RTH

RTH,

It's a shame they dont have better quality control. As I'm sure you can imagine, it's one thing to have some variance in lifting pressures between a group of injectors. But to have a relatively large portion of injectors that wont even hold pressure is terrible.

I dont want to make matters worse, but you may want to consider and oil change. Assuming your rings are in good condition, you would still most likely leak some fuel into the sump thereby diluting the oil. In the absence of a fuel diltuon tester you really cant be sure, but and oil change would be a relatively cheap piece of mind.

Didnt realize your exhaust runner configuration wouldnt allow for individual cylinder temps. On our 300SE, they're real easy.

Good luck

[RunningTooHot]

I took 10 fresh rebuilt Botch injectors to a very reputable diesel injection shop today. None of them leaked, and every one of them was actually within specification as far as opening pressure is concerned, with some variability. So technically speaking all of them would pass a rudimentary examination.

However there was definitely a difference between them regarding the spray pattern, a difference that was clearly visible even to my untrained eye. Plus the technician pointed out how some of them had a certain amount of "delay", plus some of them had a better "chatter" to them. He explained how the lesser ones would be fine, but would most likely not last as long as the better ones. This is from a guy that does nothing but rebuild diesel injectors all day long for living. I found this to be quite interesting.

In conclusion, it seems that the batch that I first received are not necessarily indicative of all Bosch rebuilds being garbage. They generally seem to be adequate, yet not excellent. Perhaps my first batch was the product of some unusual screwup at the rebuild facility -- frustrating nonetheless.

Needless to say I'll be installing the five best ones tomorrow.

RTH

[kamil]

my injectors are bad as welll..... I've had them on for about a month and now I am sending them to be tested as my car idels like crap.... bought 4 brand new bosch injectors

[TomJ]

We're going to see more of this I'm afraid. I'd bet 10:1 that they have the latest "India" nozzles. Have already had two customers who came to me in frustration saying they had replaced their injectors with new ones (actually rebuilds from the online sources, Rusty and Importedcarparts) and have tried everything, but can't get their cars to run properly.

When I pulled the injectors, ALL of the bad ones (leaking, weak spray) were the India made. When old, used German nozzles (that I've ultrasonically cleaned and balanced upon assy) were installed for a test, their cars purred like kittens (OK, maybe lions with a cold, but....)

As the stock of German and French made Bosch nozzles are used up, we'll see more and more of the India made ones and the problems will increase exponentially.

I expect that Bosch will rein this in at some point when NO one has nozzles that are useable.

One thing that can be seen on close exam (I'll try to take a pic under a magnifying glass) is that the taper on the India made nozzles is NOT polished and shows concentric machining grooves (rough), the same surface on the German AND French made ones is HIGHLY polished.