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Discussion Starter #1
Sorry the Subject field was alittle scary, just wanted to grab attention. I talked with 3 engineers today, which were in some way afilitated with the D-max. I found out that the new injectors went into all trucks built after 12-01. The problem they feel is that the injectors are developing hairline cracks that may not show up until high fuel pressure is developed. This is what is allowing fuel/oil dilution. The redesign was to address this problem but has failed. We talked in great length regarding additional filtration and th Racor setup that is being tested in Canada which is supposed to be a dealer installed OPTION. The salesmen is to try and sell it as additional at the time of sale. "Sir, thanks for purchasing your 45k truck, but we need to add the 150.00 filter setup to get you through warr"!!! I showed him the Mega and the Racor setup and he was familier with both of them.. I asked him about cavitation/air in system and its potential problems, he said there is none whatso ever and that some air should be expected in system. He mentioned the clean line test and a perfect operating system will have bubbles. I asked him why he thought that injectors were failing and he said contamination and water. Hearing that I come to the conclusion out loud that the oem filter setup is junk, he didnt like that at all. Biggest problem he is seeing is customers not changing the fuel filter often enough. He stuck with the 15k rule on them. They are well aware of the situation and at this point have no idea the exact fix for the problem. The LLY will surely help in the diag standpoint and the labor to replace.. They will go from a 96 volt system to a 48 volt system also, not sure on why. I would imagine less heat in the FICM and would require less cooling. When mentioning lift pumps, his biggest concern was damage to the FICM, not damage to the HPP as I would have thought. I told him we only run at about 1-2 psi, just enough to put system under pressure. Long story short, GM at this point dont know what to do about our little problem.
 

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So GM says contamination and water are the problem. Any idea if it's water getting past the water separator (i.e. to the injectors) or just water in the tank that's the problem?
 

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Thanks for representing us owners to those GM engineers and asking all the right questions that we have been struggling to get firmly resolved.


It sounds like we are defintely on the right track with secondary filtration and minimizing fuel contamination.


Really appreciate it.
 

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It doesn't sound like those engineers understand all they know about this problem or they were just trying to baffle you with BS. Their answer about not changing the filter is also BS. Evidently the warranty claims for injectors must not be high enough to justify a redesign, recall, etc. Changing the top of the engine to get at the injectors easier is not addressing the root cause. GM knows better but money is the bottom line. I think we are still on our own. I hope they are wrong about the cracks and dirt is the problem. Later! Frank
 

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Thanks again Eric, we all apprecaite what you do!.


Ray403Dmax - water does get past just about any water seperator (in small quantities). That's why I emulsify. Ask George Morrison just how effective a water seperator is in the 200ppm range!
 

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I am new at this but would like to add. Racor does make a replacement filter for oem that has a different ellement or this is what I am told by Racor Rep. It has the same 2 mic rateing that is in the 660 people are adding and for that fact is supposed to be the same ellement. It has a totaly different part#. And one is on its way here been tracking and is 1/2 way. It was quoted to me " the one that is OEM is of GM,s specs this is of Racor specs even though we build the filter for GM there is a big difference " The filter will be here tommarow so Ill post what I find after I see it. Well we will see and I still believe a second is a must. David
 

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Where did you order the better primary Racor filter from ?
 

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Let us know aboput that filter but so far the indications are there is only one filter to fit a DMAX and it's labeled many different ways.
 

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I got this filter from a place in spingfield Mo, by the way of a Racor tech rep.My little girl lost my paper with the name. I will have part# and puchase place and Phone# tommarow and will post it, Its is in same can, but Im assured it is of different ellement. By the way I am recieving the first free of charge for all the enquiring I did to prove thier willingness to help. David
 

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Discussion Starter #10
DmaxDave, I would be very interested to see one of them cut apart and compared. That will help tell the tale also.
 

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DmaxalliTech, be glad to help and if you would like tell me where to send it to you and you can do just that if you would like. David
 

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Monday afternoon I took my '03 2500HD ExtCab in for not starting - yup, injector problem. At 23,500 miles, I was a little disappointed in the durability. Don't get me wrong - I have been totally satisfied with the duramax/allison setup for towing my 8000lb travel trailer and 7000lb gvw utility trailer. But, I expected that other than tires/oil changes/filters, the truck would run problem free for many tens of thousands of miles.


The good news is that Monday morning (about 5 hours before heading to the dealer), I found "The Diesel Place" and was able to review the TSBs posted by dmaxalliTech. While the truck is in for the injector fix, the irregular a/c operation & "service 4wd" issues are also being fixed. Thanks to all that vocalize the issues and to dmaxalliTech for contributing the technical expertise.


The bad news is that while it may surprise many about GM's response to dmaxalliTech, all domestic automakers suffer from the same ailment - The Financial Staff runs the manufacturing. Regardless of the impact on customers, most management discussions start with "how much will this cost", instead of what's the best vehicle we can make.


As a loyal GM employee w/ 24+ years of service, I will continue to support GM. I just didn't realize that the extended warranty would be part of that support. Does anyone know Bob Lutz at GM? If we could energize him to address this issue, it would have at least a chance of being fixed right.


Steve
 

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dmaxalliTech wrote:The problem they feel is that the injectors are developing hairline cracks that may not show up until high fuel pressure is developed.


Well, it would seem to me the solution would be to lower the rail pressure below the point that the cracking is occuring. I, for one would put up with slightly less power, knowing I was getting better injector life. It would be interesting to find out the pressures and duration of those pressures, that is causing the cracking.
 

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I still say that Bosch has been making high pressure injection systems for awhile and I am sure they know how to make them. IMHO it is still dirt related. We were saying that only 01's had the problem well guys its all the way to the 03's now. I think real world results and George Morrison have a lot better handle on the problem than the boys at GM. With the help of George and everyone putting on extra filtration I serious doubt you will see injector failure in those trucks again or at least it will not be in the near future.

Greg
 

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At least they know and they know WE know and have been working on solutions without their help. Hopefully they are taking some of these corrective actions seriously.


I have to agree with Steve though. Some of the best solutions haven't been implemented due to how businesses are operated and the bigger the company the tougher it is to do the right thing engineering wise.
 

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Discussion Starter #16
Pick said:
dmaxalliTech wrote:The problem they feel is that the injectors are developing hairline cracks that may not show up until high fuel pressure is developed.


Well, it would seem to me the solution would be to lower the rail pressure below the point that the cracking is occuring. I, for one would put up with slightly less power, knowing I was getting better injector life. It would be interesting to find out the pressures and duration of those pressures, that is causing the cracking.

The sad part is that they said they will be increasing fuel rail pressure not decreasing it
 

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Right now super clean fuel is all we can do. We are at the mercy of Bosch and GM. Now they need to look at what they need to do to avoid a sales meltdown if this turns out to be a 100,000 mile if your lucky issue.

I would like to know what is causing the hairline cracks?

Just the fuel pressure itself and a faulty injector design or faulty manufacturing? Sounds like an injector redesign is due. But then getting GM and Bosch to work together may be the same as getting GM and Stanadyne working together.

I don't understand where dirt and hairline cracking are related unless abrasive wear weakens somthing.




Something to note....

The new VW V10 diesel coming out does not use HPCR.



source said:
Other VW TDI models with the 1.9 litre 4-cylinder of 115 hp or 150 hp, and the 1.2
litre and 1.4 litre 3-cylinder engines, use a so-called "pumpe-deuse" (German) or
"pump-nozzle" (English translation) system. In these engines, each cylinder has its
own small high-pressure fuel pump which is actuated by the same camshaft that
operates the intake and exhaust valves. Fuel is delivered to each pump-nozzle by a
low-pressure pump serving the same function as the internal vane pump in the
distributor-type system. As the engine cylinder approaches the end of the compression
stroke, the main pump plunger advances, pressurizing the fuel. A solenoid valve
adjacent to each pump-nozzle is normally open and bypasses the fuel. When the
solenoid valve is energized, the bypass passage is closed and the fuel is forced to an
extremely high pressure and through the injection nozzle. At the end of the required
injection period, the solenoid valve de-energizes and any remaining fuel pumped by
the plunger bypasses the nozzle. Thus, fuel is injected as long as the solenoid is
energized, allowing full control of injection timing and duration. This system has the
significant advantage of eliminating the separate high-pressure fuel lines from the
pump to the nozzle because it is all built into a single unit, thus giving better control of
the injection cycle.
Finally, some modern diesel engines use a "common rail" injection system. The
concept is much like a conventional gasoline engine EFI system but the pressure
involved is on the order of 1000 times higher. A single central high-pressure pump
delivers fuel to a pressurized fuel line, and separate solenoid valves on each cylinder
admit fuel into each injector. Although this sounds simple, it is extremely difficult to
make it work due to the extremely high pressures involved. This system is used on the
180hp version of the 2.5 litre V6, and on the 3.3 litre V8.

From SourceEdited by: hoot
 

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The solution is easy enough, just add one of the supplemental filters (Cat, Racor or Baldwin) to your truck and use an emulsifying additive. Just what George Morrison said when this whole filtration issue was started on The Diesel Page back in October of 2002. The story has not changed.





Eric - thanks for posting the information above. Enough bits and pieces of factual information are eventually reported on these internet forums to where the big picture can be put together.


Alan
 

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Eric, reading your conversation, it didn't sound like they were saying that the high pressure was causing the hairline cracks. Only that the cracks were apparent because of the high pressure. Did I mis-read this?


Steve
 

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Eric,


Thanks for sticking your neck out and "come(ing) to the conclusion out loud" that the OEM is junk. So, how hard was it to not slap him up side the head and tell him to wake up?



Let's check the logic of this. First, you have hairline cracks. Second, it dumps fuel into the oil and dilutes it. Third, your redesign didn't fix it. Forth, so you INCREASE the pressure?
Fifth, you are worried about the FICM and not the HPP?
Nevermind, there is no logic to this.



The flow with a lift pump should be more and not less for cooling purposes. If you are vaporizing the fuel in the FICM because of it beign at a lower pressure, then the cooling is not as efficient. These guys are confusing me and worrying me too.
 
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