Is anyone aware of a study to determine the root cause for injector failures and where it can be found? In my opinion, lubricity and faulty design could just as well be responsible for the failures as particulate contamination.

I'm trying to determine if there is a measureable improvement in injector life from additional filtration. Any experiences or opinions would be appreciated.

Is anyone aware of a study to determine the root cause for injector failures and where it can be found? In my opinion, lubricity and faulty design could just as well be responsible for the failures as particulate contamination.

I'm trying to determine if there is a measureable improvement in injector life from additional filtration. Any experiences or opinions would be appreciated.


Good question. No one can answer it

On a familiar note... did anyone analyze the poll on injector failures that was/is floating around? % of affected ...by year, mileage, performance level, etc.

Had a secondary Nictane filter on mine since about 2000 miles, replaced injectors 2 and 4 at 12,000 miles, used standyne lubricty all the time too. Filtration and / or lubrication won't eliminate all failures, not sure if there is any data that it prevents any. It makes sense on paper but not nessassarily in the real world based on my experience.

Just to throw a kink in this, my '02 has 105k miles, factory filter changed at least every 15k, no other filtration. I used stanadyne for a while and now using Primrose...occasionally. Still on factory injectors. I guess I'm one of the lucky ones.

MaxRock

There is no formula or sacred method. Some have three filters and additive and premium fuel and bam, they fail. Others run one filter, rarely changed, poor fuel, and they go or 150K+...

As Hoot said, No answer

84,000 miles and still on original injectors. I have a Mega filter system that's been on the shelf for a year waiting on the plug and play unversial harness from JK. I only use additive outside the DFW area. That means not every often on additives. SD is making me a HP lift pump system so the Mega will go into truck in a few weeks.

You can bet that GM / DMAX LTD / Bosch have been performing failure analysis on most of the failed injectors. I know of one individual who works for Garrett (the turbo manufacture on the LLY) and they receive ALL failed parts. They do a complete failure analysis to try and determine the mode of failure and root cause (both for product improvement and for determination of financial responsibility).

For the 2001 and 2002 DMAX owners, I believe GM gave a little insight into the injector mode of failure in the letter the owners received: 1.) erosion of the ball seat and 2.) cracked injector bodies. They did not mention the root cause.

We can speculate that for ball seat erosion, a partial cause could be the particulate count in the filtered fuel. They have recently changed (and rumor has it "improved") the construction and filtration capability of the fuel filter. Coincidental ? ( I doubt it) For the second mode of failure (mentioned in the letter as cracked injector body), that could possibly be a materials property issue, a stress issue, a thermal issue,,,, and the list goes on.

Articles published by the SAE have shown conclusively that by lowering the particulate count in the filtered fuel you increase the longevity of the injector (from an erosion point of view). That is just one component of the final determination of injector life. As mentioned earlier, lubricity is another important factor. In the end, some other problem may pop up and cause a failure.

Have any of you heard about the ford guys modifying their fuel lines to get away from the quick disconnect fittings? They think small amounts of air get in through there and cause cavitation at the injectors and that causes failure.

Have any of you heard about the ford guys modifying their fuel lines to get away from the quick disconnect fittings? They think small amounts of air get in through there and cause cavitation at the injectors and that causes failure.
So it would seem that a lift pump in the tank, or at least one rail mounted near the tank with minimal fittings, would eliminate that as a reason.

Jim

There have been a few guys that have done that in the Dmax world, but sure sounds like a lot of work and a lot of risk when the average dealer see's that and gets all wound up...unproven .

I agree with OC Dmax, alot of speculation. The letter seemed to identify what they had deemed the reason for failure but have not answered the question why. I know Bosch is taking a Bath right now.

I went right to 100K before mine failed. Got new ones and we will see. I was one that maintained my truck very well. New filters every 10K, Total Power additive, Nicktane Cat Pre Oem, quality fuel(I always used to pump a quart into a jar at fill up to check clarity). Now I will still PM like before and replace secondary filter at 10K(Using Wix 33910 rather than Racor). Short of that, I think this is still unknown......

filter every 7500 ish..no additives..23k miles..factory injectors.

I can imagine that it has to do mainly with the fuel quality available in the US. Since Bosch is supplying millions of injectors to just about all European Diesel engines (over 40% off all new passenger vehicles have Diesels) I would be surprised that they donīt know on how to design an injector. It is possible though that it was assumed that a system design as it is used in Europe would work just as well in the US....and now they are stuggeling to get that to work as reliably as in Europe. I wish I had a DMAX over here already and could report about it. All I can say is that I am not aware of Diesel owners having to add filtration to the fuel system or fuel injectors as such a big issue...sure they will fail every once in a while but nothing to talk about regularly.

Just my 0.02 Euro = 0.0261995 US ;-)

A Bosch employee told me that they had a mix up on the production line. Seems that the spray orffices from there 900.00 dishwashing machine got labled as Duramax injectors. We have been running plastic dishwasher parts the entire time. Who new. Wonder if some jetdry rinse-aide mixed in the fuel tank would help.

A Bosch employee told me that they had a mix up on the production line. Seems that the spray orffices from there 900.00 dishwashing machine got labled as Duramax injectors. We have been running plastic dishwasher parts the entire time. Who new. Wonder if some jetdry rinse-aide mixed in the fuel tank would help.

Yea but the dishwashers last forever ):h

A Bosch employee told me that they had a mix up on the production line. Seems that the spray orffices from there 900.00 dishwashing machine got labled as Duramax injectors. We have been running plastic dishwasher parts the entire time. Who new. Wonder if some jetdry rinse-aide mixed in the fuel tank would help.
Now that there is hilarious!!!!!!!!!! :ro)

Ben

I can imagine that it has to do mainly with the fuel quality available in the US. Since Bosch is supplying millions of injectors to just about all European Diesel engines (over 40% off all new passenger vehicles have Diesels) I would be surprised that they donīt know on how to design an injector. It is possible though that it was assumed that a system design as it is used in Europe would work just as well in the US....and now they are stuggeling to get that to work as reliably as in Europe. I wish I had a DMAX over here already and could report about it. All I can say is that I am not aware of Diesel owners having to add filtration to the fuel system or fuel injectors as such a big issue...sure they will fail every once in a while but nothing to talk about regularly.

Just my 0.02 Euro = 0.0261995 US ;-)Are the European Bosch systems high pressure injection like the US? Doesn't make sense to me with what seems to be the same failure rate with secondary filtration and lubricity for many folks.

I myself have no secondary filtration, buy all my diesel from a truck stop, drive at least 60 hwy miles every day, change my filter about every 5 to 7k. And have used only very little fuel additve (Rottela Fuel Additive) because the manual addresses not to. And after 1yr and about 24k, I had my injectors replaced. I talk to my local mechanic that has a 2500HD but gas, says he thinks it may be fuel quality. His brother has had 2 duramaxs and uses off road fuel in South Dakota and has not had any replaced. Could this be a factor?

Fuel quality is known to be a large problem, Europe has much better quality fuel and that is no secret. They use a much higher precentage of diesel powered vehicles then we do here in the states. A lot of the Bosch HPCR testing was done in Europe and it all worked fine over there, they brought it over here...... well you know the rest.

I have an extra fuel filter at the in-bed tank, that is the primary fuel tank. I have had the extra filter since one day after purchase of the truck. Also every several tanks of fuel i use an additive. My first injector failure was at 215k. I believe the extra filtration helps,as reading the 2 forums,many have had failure's long befor I did.

Are the European Bosch systems high pressure injection like the US? Doesn't make sense to me with what seems to be the same failure rate with secondary filtration and lubricity for many folks. Most manufacturers use common rail systems, all high pressure. VW is following a slightly different approach by having an injector that is the high pressure pump at the same time. These systems run even higher pressures. They are called PD (Pumpe Düse = pump metering) type injections.
If you are interested read this ARTICLE (http://www.dieselcar.com/pdf-files/articles/power/power08.pdf) to find out more....BTW my daily driver is a smart 42 which has the smallest common rail diesel in the world 800cc,
74ft lbs, 41hp. Mated to a 6-speed automatically shifting manual tranny.
Here is a pic with the Moon Discs I bought recently :

http://duramax.de/smart_moon.jpg


Here a pic of just the engine (weighs 143 lbs !!!!):

http://www.fram.nl/workshop/engine/smartmotor2.jpg

the fact that most trucks regardless of year, mileage, filtration, additive, etc apparently don't have injector problems leads me to wonder if quality control (or a lack there of) at Bosh during the manufactoring process could be a major part of the problem ... seems to me that if it was a problem with design or materials used, failures would be more universal further if it was a fuel quality problem those with excellent aftermarket filtration wouldn't be having problems

Jim

I will keep my secondary filter thank you very much. I know it works regardless whether or not some one has a failure running two filters. We covered all this a couple years ago when we were building our kits. Some of the big diesel manufactures did studies and that data said to use better filters. I posted some data on 46K water cutters that had to filter the water to 1 micron to keep from washing out ruby nozzles. A lot of the precision parts inside the injector see high pressures. No, I don't think for a minute a second filter will eliminate all failures. I spent 35 years in industrial maintenance. We did predictive maintenance, preventative etc. S**t happens for no apparent reasons some times but when you find sometimes that helps you use it. GM knows what part of the problem is. They sent a letter to their dealers telling them that small micron particles are a problem, they unofficially blessed a Racor secondary filter kit and redesigned the OEM. Cracked injectors! Simply a QA problem with no acceptable excuse. I have said this before but for the benefit of the newer members I will repeat myself again. The second filter should be the first accessory you put on your truck. Later! Frank

Heres a question from far left field. Could it be possible that the proformance add ons like Banks, Edge, etc. are causing premature injector failures? Now I know there are guys with totaly stock rigs with injector problems, but it seems like alot of guys with problems have some kind of add on. Or am I just dreaming? This is just something I just thought of. Aren't those add ons all about more fuel and timing? I don't know, thats why I'm asking. What do you guys think? Just a thought.

Related to the last question - I noted that the stock fuel filter has a state flow capacity of 46 gpm. I found a formula for determining fuel rate needed - rough calculation dependent on hp - with mods a truck would need near 60 gpm.

Another thing to note is that racor states that lift pumps are not ideal and that vacuum side pumps are better for two reasons..

1. The lift pump stirs up the fuel and emulsifies water making it more difficult for the filter to seperate it from the fuel.

2. I don't know the technical reason why - but they state that fuel filter efficiency is lowered if you put it under pressure (versus vacuum). i.e. lift pumps do have some downside...

- jeff

Related to the last question - I noted that the stock fuel filter has a state flow capacity of 46 gpm. I found a formula for determining fuel rate needed - rough calculation dependent on hp - with mods a truck would need near 60 gpm.

Another thing to note is that racor states that lift pumps are not ideal and that vacuum side pumps are better for two reasons..

1. The lift pump stirs up the fuel and emulsifies water making it more difficult for the filter to seperate it from the fuel.

2. I don't know the technical reason why - but they state that fuel filter efficiency is lowered if you put it under pressure (versus vacuum). i.e. lift pumps do have some downside...

- jeff
Based on less media usage of vacuum side filters I would have to disagree.

I think GM saw dollar saving with the single pumps unit. Anyone that has worked on hydraulic systems or pumps very long know the short comings of a suction/vacuum system. If the tank was at or above the pump inlet all would be well in Duramax land. Later! Frank

Dang Lennart, I think I have found the motorcycle engine I have been looking for. Any programers for those over there yet? Bet that thing gets 80-100mpg (34-42kpl)?

Based on less media usage of vacuum side filters I would have to disagree.What you are seeing is that the lift pump stirs up the asphaltines in the fuel. A more homogenous solution would also more uniformly coat the fuel filter. Without the lift pump the bigger and heavier tarballs fall to the bottom of the filter and end up getting sucked into the bottom of the filter media.

One of the docs on racor's website isn't available right now - a bug in their website. I did find the following statement in their diesel fuel filter docs on filter installation (and selection) :

"Racor units are most efficient when installed on the suction side of the fuel system"

look here (http://www.parker.com/racor/pdf/7480G/pdf/Section02.pdf).

-jeff

LoL, I have a Bosch Dish machine so I guess I know where to get parts if I have any failures ! ):h ):h

Those Powercroakers suffer cavitation problems primarily from the air vortex that is created by Duramax's blowing by them at a high rate of speed ! :ro) ):h

Dang Lennart, I think I have found the motorcycle engine I have been looking for. Any programers for those over there yet? Bet that thing gets 80-100mpg (34-42kpl)?
A dozen programmers at least !!! hp ratings up to 65-70 can be done. Keep in mind that all tunes available here would be smog legal....so there is probably more power available.
The milage I get is about 60mpg ... the best I have seen reported over a longer period of time is 78mpg.
BTW, this engine has been transplanted into a motorcycle already....see here:
http://www2.fht-esslingen.de/fachbereiche/fz/?menu_id=130
Itīs all German but take a look at the pics. The mart engine has also been transplanted into yachts, ultralight aircrafts to name a few.