My Komatsu excavator is low on boost pressure and the more i learn about this VGT turbo the more I think the system is much more complicated than it needs to be. Id like to throw the vgt off and put on a traditional turbo. Can I just plug off the oil lines that control it or would I need to link them together to let the oil flow?
Someone might say different but I think the ECU is looking for variable geometry position data. Even if not, the maps are going to be designed for that so going back may create some issues in RPM management due to lag. You should be able to disconnect the VGT actuator arm and confirm it functions right. If so, chase the actuator side of it. VGT has been on the 6.7 and the Duramax for a long time without much issue. I recommend fixing the problem.
Try looking for vetechs thread on this exact same issue. Then try changing your oil with a quality oil and new filters.
Just as additional info, I am very involved with electronics and if your Ex runs the same actuator as the trucks, they put a PCB (circuit board) right on the turbo. Not in my lifetime would I ever design a system that way. We measure electronics life by a few criteria and temp exposure is one of them. It might be worth you pulling it and having a VERY experienced EE comb the circuit to see if there is an obvious issue. Off the cuff, due to the environment, I would be looking for failed solder joints and cooked capacitors. Again, this is assuming the issue is the actuator and not the linkage system in the turbo. That needs to move free.
There is no external linkage. It is hydraulically controlled. There are inlet screens at the turbo and at the EGR. This has all been laid out, in detail. Like 3 or 4 pages worth iirc.
Obviously I don't understand your system to help you but I will say if there is a position sensor of any type on the turbo, that will be a problem in a delete as the ECU will want that data. I will bow out and see if someone with direct experience with them can help. No sense in me providing unrelated info.
Lets start at the beginning. Do you have error codes related to VGT, EGR, or anything along those lines? What are you basing your theory of low boost on? Actual numbers or not readily being able to hear the turbo spool up? Do you have the service manual and know what a PM clinic is? Are you lacking breakout force or lifting abilities? Cuz, I know, our Komatsu guru, John C will be along soon and i don't think anybody on here regularly, is as sharp on these as he is. He'll probably want the same answers.
Gee, thanks for the build up. I hope I can live up to the expectations. All the questions above are spot on. I’m guessing that you are perceiving a performance problem? Boost pressure is only attainable at full load so the first question from me would be have you done any cycle time checks? Boom up times should be around four seconds. What have you been able to check from the monitor panel? Do you know how to get into the diagnostic sections? Turbo chargers have two or three failure modes. Bad air filters, dirty engine oil and over speed. I don’t know squat about these fancy new turbos but do remember all kinds of issues with the waste gate units of a few years ago. I don’t understand why this level of technology would be necessary on what is very close to being a generator engine. Even so I never tried to second guess the engineers. Might be fun to watch. Keep us updated.
John, the VGT turbo deal was primarily targeting emissions. As you know, when you throw the coal with a heavy load, that is when things get sooty. Getting the turbo lag reduced helps get combustion quality in compliance faster. I would guess because an Ex is constantly subjected to light-to-heavy loading, and auto idle downs, that the VGT could be beneficial.... Also some perks on the performance side for sure! In general, a designer can select more aggressive turbo geometry (higher boost) and still get good spool up. I would generally agree and question the reliability of VGT for an industrial piece where reliability must come before everything.
Here's something else to consider. If the ports on the egr differential pressure sensor are clogged. It will effect the vgt operation. The computer takes egr data and uses a algorithm to adjust the vgt. This is true for any engine with egr and vgt turbos.
Soot production was never an issue with Komatsu engines. The high injection pressures for the time made Nox the issue and reason for the Cummins clone motors in North America. I am a bit surprised to hear that Komatsu might still be using Cummins. I haven’t seen that around here.
Oh yeah, Komatsu and Cummins are in bed together for the long haul. All the smaller power plants are 4&6 cyl Cummins but they have goofy identities. SAA6D107E1 and so on, which i think translates to 6.7 liter B series with bastardized intake and exhaust and fuel system.
I’ve been seeing the 95 series Komatsu engines in the Dash 10 series out here. Komatsu and Cummins have been joint partners since the sixties. I seem to recall the B Cummins being a 5.9.
Yeah , 6BT8i>> series was 5.9. With the introduction of emissions they had to increase displacement to 6.7 just to maintain torque and horsepower. The intake and exhaust restrictions were choking that badly. Between heavy duty pick ups, yard mules and any other piece of equipment that ever had the 5.9 as a power plant the power couldn't be maintained with the existing configuration. As the old saying goes, "there's no replacement for displacement. "
Good to know. The B series was underpowered in the excavators and wheel loaders as well. When they came out, we got a ton of complaints. There were also lots of weird issues that came up all the time as well. No power, lots of smoke, bad or mis adjusted fuel pumps, lots of blow by, sloppy rocker arm centers, worn rocker arms where they contact the valve heads. The C series were worse as they were too small to carry the machines they were installed in. PC300 excavators and all in the wheel loader lines were just crap. Then they put L10/M11 in PC400 and about killed their business. I did an inspection on one for the dealership or Komatsu because there was some distrust about the stories from the customer. The engines were just not up to the duty cycle required of excavators and wheel loaders.
I don't think there is any question that emissions crap has taken bullet proof reliable power plants and turned them into drama queens with no legs or tits. On the engineering side, I defend designers a bit because the engineers truly know how to build a bullet proof system, but the emissions crap becomes a compromise and they well know it. I do appreciate the little "push" the EPA has given towards tech advancement, but I think the quest for fuel efficiency alone could have driven that! Look at turbine engine competition. Cutting edge engineering is driving the limits of efficiency. I don't know too much about Volvo, but all I ever hear about is their injectors. Always something to do with injectors. Not sure if they are pushing it on rail pressures or what.
We're getting way off topic, until the OP shares what he's up against, let's continue. Volvo, in comparison to Cummins runs low rail pressure. Their injectors have zero tolerance for water intrusion. On the big bores, they switched over to conical seats, nothing but problems there. You have to change the cup each time you do an injector. That's ridiculous.
I agree with the opinion of Mr.Fastline. The Komatsu -10 has up to 3 controllers, which communicate with each other by means of a "can-bus" network. If you replace it with a traditional turbo, the ECU will report an error and even the pump controller, monitor controller will report an error resulting in the machine not being able to work!
I also have to agree with you on this point. When modifying the turbo, we also need to consider the handling of the EGR unit. The reason is simple, if the EGR is open, surely the turbo speed will be reduced, leading to a decrease in engine power.
I really hope that i can find a way to put a traditional turbo and get rid of the goofy EGR too. Not a fan of piping exhaust back into the intake. Motors run better on clean fresh air in my opinion.
It will be easier and likely cheaper to fix it the right way. Unless you know someone who can properly delete and reprogram your ecu. Then you are just asking for more expensive problems than repairing the issue at hand. You never gave a full explanation of the problem. How do you know that you have low boost? Do you have any active codes? Any other symptoms or anomalies not mentioned? This could be something as simple as cleaning the venturi tube of the egr.
Low boost was determined by look at boost pressures on the monitor. It seems to be correct because machine has lost some power too. I think Ive found someone to flash the ecm for me, Hope he knows what he is doing! Its important for my wokr to not have the dpf get hot on regen. I am doing clearing work for ranchers and so im in a lot of leaves when working. Ill burn this machine down if I have 1300 degree exhaust. It doesn't have a current active code.
Clogged air filter can cause low boost. Leaks in the charge air piping. And the vgt acting up. These turbos pretty reliable. The only thing I seen that would mess with the operation of the vgt without causing a code. Is a Clogged egr differential pressure sensor ports. What I see happen is that exhaust gas will get trapped and make the sensor read inaccurately. This will have the ecu change the position of the vgt to undesirable position. I strongly discourage the deleting of emissions. Not because I am some sort of save a tree and hugs for you and me kind of person. And I could give a crap about government regulations. My concern is that if the person doesn't know what he's doing. Then he can ruin your engine. There's a lot more to it than block off plates. This is a science to do proper deletes. And I can only think of a few mechanics of the many I know that would understand the idiosyncrasies of something like this. You are only getting those high temperatures at the exhaust tip. The heat desipates pretty rapidly as distance from the exhaust outlet. And if this is a teir4 final machine then it does it passively at lower temperatures. The only time that you get to those higher temperatures is during parked and service regeneration. I have been doing this for a long time and I have only seen one proper delete. The rest were shadetree hackery. It works,but when they fail. The hacker doesn't know how to fix it. And then the dealer gets involved and they won't touch it unless you go back factory emissions.
So you're asking for help to delete. A delete is not gonna help your performance issue. Sorry but I'm out
You're right Mr.Paul, The point is that it takes an expert who is very knowledgeable in how to program the engine ECU for industrial engines. We reprogrammed the PC350-10 ECU to remove the DPF handling. We're currently working on reprogramming to remove the handling for VGT and EGR, but we're not done yet! We have just had to replace the VGT of PC350-10 with a new one, it's very expensive!!!
Low boost causes a lack of speed not a lack of power. Power is a function of hydraulic pressure and flow settings on the pump. You haven’t stated if you did any cycle times. You can’t measure boost without fully loading the engine.
looks like you have the reprogramming that I want
I'll try cleaning out the EGR and see if that changes anything. Thanks
I believe that is what I'm using to monitor boost, vgt, egr, etc It seems to work pretty good when it's cold but deteriorates as it warms up. I thought I would take data snips and show the boost was falling off at certain vgt or egr positions but that isn't how it came out.
Based on the pictures you have attached; I assume your VGT is in good working order!! According to the standard table recommended by Komatsu, the minimum pressure is 120 kPa (17.4 psi), while your engine pressure reaches 164 kPa (23.9 psi).
Man, wouldn't that be nice to get all that data at your fingertips in a CAT!!! You might actually be able to diagnose and fix something in the field.
Throttle position at 76.4% and you have 23.929 PSI?
Komatsu technical support told me that I had to subtract ambient pressure from the monitor figure to get true boost. Maybe he was wrong?
I don't think so, man. we only have to subtract the ambient air pressure when the value in the standard table is the gauge pressure value, and the value on the screen is the absolute pressure value. We can do a thorough check with a turbocharger pressure external gauge which we can buy easily for a very cheap price. Komatsu's manual also instructs us in the same way (Please see attached file). We also can read here about 02 types of pressure values: https://blog.wika.com/knowhow/difference-between-gauge-pressure-and-absolute-pressure-measurement/ Very cheap turbo boost pressure gauge: https://www.amazon.co.uk/Universal-Turbo-Pressure-Smoked-Indicator/dp/B071SD2J6Q
Does anyone else get all giddy and excited when LACHAU posts?..........or is it just me!?
for further clarification: I have noticed that the technical documentation always uses gauge pressure values throughout all sections of the document. Technician Komatsu's argument is "ABSOLUTELY" absurd.
An easy way to determine absolute vs relative pressure is look at the boost pressure when not running. Obviously should read 0 if relative. As well, it might be a good idea to ensure the boost sensor is working right. An engine should not be throwing fuel at the party until it sees enough air (boost). In a pinch, I have just rigged a hand air pump in a little tube to throw air pressure at the sensor while coupled in the harness and can be read when not running in a diagnostic screen. Once you can confirm it works right, you can have more assurance in the value you see. So many people buy whatever is on an LCD screen, hook, line, and sinker, and not qualify the sensors. They can lie to you. Just remember to look at all available data. vane position would be pretty important to me in this one but if that is not available, I might be looking at the hydro pressure to it.
So I got a chance to play with a machine like mine. Cold boost pressure and turbo speeds are on par. I just have to figure out why mine looses boost pressure when it warms up. Is it possible to have a soot restriction in intake as a result of EGR? Excuse me if that is a dumb question bit I don't fully understand egr operations. My only experience with them is throwing them off of a couple of 6.0 Ford superduty pickups.
I suggest you check more parameters like the table below when the engine is cold and when the engine is hot.
I think I would take your cold vs hot testing much further. In many cases, low boost is a product of something else going on. While cold I might throw the machine on a relief and record all the data you can. Then do the same hot. Stuff that I would certainly want to look at is injection event pulse width if they offer it, but "throttle %" might be all you get. Fuel rail pressure, etc. Everything to do with fuel. One hunch I have is high return rates on your injectors which would cause low rail pressure, but typically would also present with wider injection pulse width as it is trying to get more fuel. However, I don't recall what fault codes are being presented currently, if any? Those codes or lack thereof are an important piece.
Since there are many sensors used as input parameters to the ECU to process and control the VGT , we must read to keep track of all these parameters. In addition, we also need to pay attention to the lubrication system and cooling system for VGT . I think that the change in speed reduction of the VGT unit when the engine temperature increases are also partly affected by the two systems mentioned above.
thanks Ill try to get those tomorrow
I found a missing stud on my intake heater. With the insulator missing also its almost a 3/8 inch hole. Hopefully that is my boost leak. If so, it only showing up when warm still is confusing to me.
I'm sure the expert will arrive shortly but I don't believe an air leak there will cause a spool issue with your engine, but can certainly allow unfiltered air to enter the engine which could cause engine or turbo damage. Let's hope that is a minor leak. Did you do any blowby testing on this engine? Can you visibly see the turbo compressor wheel at this point? Check turbo for axial and radial shaft play and visual inspection of fins and clearance to housing.
The intake heater on this motor is located after the intercooler and before the EGR. Its pressurized there so it shouldn't suck dirt in, should blow it out. It was blowing air out when I found the hole. Testing it cold I got 2 lbs more boost than prior. Im anxious to test it warm to see if this is the only issue.
Man, that would be a find! However, that would have to be a very serious leak to blow all your boost away there. Certainly worth the test and glad to hear your grid heater is on the pressure side. Maybe you can find some more leaks!
I was still getting boost around 22lbs cold and 18 warm. You dont think a 3/8 hole is a serious enough leak to cause my problem?
I would have thought those were studs going into blind holes. Cold air is more dense so I could see a change in charge air pressure with an open hole like that.
I was under the impression that the air leakage was occurring between the gasket surfaces due to missing one of the corner bolts. Yeah, if that bolt or stud actually enters the pressurized air passage, that would be more air. Still though, you have to remember turbos are designed to be HVLP air delivery. They move a lot of air, especially up on turbo curve. Give er a good test and hopefully you found it! But I was under the impression all your boost was going away? I can certainly argue from the engineering side how the air density changes from cold to hot would have more influence and pressure loss when hot. That part does make plausible sense. Without going way overboard explaining fluid dynamics and air springs, basically as the pressurized inlet air gets warmer, it gets harder for the turbo to achieve target boost pressure due to reduction of air density. It is moving the same "volume", but less dense air is more "springy" so it is harder to compress, especially with a leak. Keep us in the loop!
Worked it for 5 hours today with no issues so I think the missing stud was the issue. I think Id have found it sooner if I wasnt perplexed by it only doing it hot.