Power Problem with FM260
- Thread starter JRhetts
- Start date
JRhetts
Adventurer
mog
yes that url was loaded. I especially found Table 4 on p.6 in section 3 interesting.
I read this as Mitsu saying that they do not expect more than 13% loss from even a 4x4. So why did I feel that their characterization of of my 23% loss as "very slight" to be very much of a slight?
Very helpful graph! I included it in a letter I sent to the dyno test facility today, asking whether they could do better. We'll see. I superimposed my dyno data to make the point that the curve is what is important, and that either my engine was very sick [deviant from the standard] or the data they gave me is way off.
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mog
Kodiak Buckaroo
I believe that is just one component in what we are calling parasite loss.
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"The engine torque (T) given in the truck's specifications conforms to the Japanese Industrial Standards (JIS). It is multiplied by a factor of 0.95 to compensate for the 5% loss resulting from restrictions placed on air taken in through the air cleaner and the back pressure in the muffler and tail pipe. The torque (T) is also multiplied by a factor - normally 0.913, representing mechanical efficiency - to compensate for the mechanical loss of torque due to friction of the transmission, propeller shaft, and rear axle. The value of this factor differs with the type of drive system used, as indicated in Table 4"
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So your 'advertised' torque (516) time .95 = 490. That time the .876 = 429. Now if they say a 5% loss for intake and exhaust, what about all those parasites mounted to your engine, alternator, A/C compressor (even off there is some drag from the belt/etc), fan drag (that can be a fair amount), maybe even water pump was not included in advertised 'power'. So maybe another 5% (429x.95=407) or 10% (429x.90=386).
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O-ya, BUT you are not so luck to get to take those losses progressively (we are not doing our income tax here :sombrero: ), they happen all at the same time. So you would have the stated loss of the 5% intake/exhaust and the 13% driveline (516x.82=423) or with another 5% (516x.77=397) or with another 10% (516x.72=371)
I'm not sticking up for Mitisubishi, but I do believe 'advertised power' and real life are pretty far apart.
JRhetts
Adventurer
My [estimated] position Nov 15
a. The ‘adjustment’ I devised to gain 4psi at the intake manifold does not in fact solve anything. If anything running at 22psi vs 18psi incurs a slight performance penalty.
2. The dyno results I got Monday are utterly unhelpful. But since the engine runs completely reliably and consistently under all real conditions, the dyno data curve does not seem to be a good characterization of my engine. Maybe the test center will offer to do what I wanted and make good on my time/$$ investment, but I am not holding my breath.
iii. Because more boost does not make more power, I could accept the engine’s performance at 18psi boost, and get back to driving.
D. Or I could try to look at the fuel side. As Andrew said in post # 142: “boost does not make power, fuel does. you dont get anything for free. boost allows the motor to burn more fuel and still be cool/efficient”
5. Evaluating the fuel side without a MUT-II/III tester is more than a bit daunting. From the Manual, I do have the resistance values for testing the various sensors, so I could remove and test each of the relevant ones. My rough count is that there are at least (8):
As always, comments and suggestions are welcome.
John
a. The ‘adjustment’ I devised to gain 4psi at the intake manifold does not in fact solve anything. If anything running at 22psi vs 18psi incurs a slight performance penalty.
2. The dyno results I got Monday are utterly unhelpful. But since the engine runs completely reliably and consistently under all real conditions, the dyno data curve does not seem to be a good characterization of my engine. Maybe the test center will offer to do what I wanted and make good on my time/$$ investment, but I am not holding my breath.
iii. Because more boost does not make more power, I could accept the engine’s performance at 18psi boost, and get back to driving.
D. Or I could try to look at the fuel side. As Andrew said in post # 142: “boost does not make power, fuel does. you dont get anything for free. boost allows the motor to burn more fuel and still be cool/efficient”
5. Evaluating the fuel side without a MUT-II/III tester is more than a bit daunting. From the Manual, I do have the resistance values for testing the various sensors, so I could remove and test each of the relevant ones. My rough count is that there are at least (8):
1. common rail pressure sensor
2. boost pressure sensor
3. boost air temp sensor
4. water (coolant) temp sensor
5. fuel injector rate adjustment resistor
6. suction control valve
7. fuel temp sensor
8. engine speed sensor
I left the accelerator position sensor off the list, as the tech explicitly checked that at my request on Monday during the dyno test.
As always, comments and suggestions are welcome.
John
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Ruderacing
New member
Most pyro's are mounted after the turbo in the dump pipe. The Temp wont be as hot as directly at the manifold but it is all proportional. Mine is about 200mm down stream of the turbo and reads fine. Seriously though due to the fact you cannot change the amount of fuel going into the engine due to it being electronic its probably a waste of time.
I have spent hours doing what you have done doing road testing and adjusting the fuel pump (mechanical pump) to get the most power out of it but in the end all you are doing is guessing. I eventually just put it on a dyno and bang you know exactly what it is doing and how far you need to adjust it.
Money well spent, but it needs to be done right of course...
I have spent hours doing what you have done doing road testing and adjusting the fuel pump (mechanical pump) to get the most power out of it but in the end all you are doing is guessing. I eventually just put it on a dyno and bang you know exactly what it is doing and how far you need to adjust it.
Money well spent, but it needs to be done right of course...
Ruderacing
New member
Yes sorry I should have been more specific.
What I meant was as it isn't a mechanical pump that is very easily adjusted by anyone, compared to something like an ecm controlled pump which is not easily (if at all) adjusted by anyone other than the factory. I would doubt the Fuso dealership will even have the gear needed to make that type of adjustment.
Manufacturers do not like people messing around with their ecm's even by their own people. That has been my experience in the HD market anyway.
If the dealership cant perform a proper dyno run then you will have next to no chance of getting them to adjust the fuel delivery set points.
JRhetts
Adventurer
kerry
That's a good question, and given my rudimentary knowledge I probably should not attempt an answer... but "fools rush in where angels fear to tread."
First, as Ruderacing suggests, a mechanical system might let us manipulate variables directly.
However, with an ECU controlling the fuel variables and output, I am not sanguine about being able to program anything. Both my chip-builder friend and an experienced Fuso shop manager have told me that: the Mitsu MUT-II/III tester is the ONLY way to read/communicate with with the ECU; this equipment does NOT allow any 'programming' short of re-flashing some Mitsu-blessed code — which has not been provided for the FM in several years [my 2007 model has up until now NOT been the target of any authorized re-flashing from Mitsu].
My chip builder friend has described the Mitsu data that appears at what looks like an OBD-II compliant port in the glove box as: 'the ultimate in proprietary encoding.' I have personally tried 6 separate reader/de-coding tools that he provided to me – to absolutely no avail. We could not even read the diagnostic codes we knew were stored, much less do anything else.
However, maybe someone else can get into this CAN bus and figure out how to mess with the programming. I'd love it!
I'd love to, but as yet I have not encountered any Mitsu officials that appear to be motivated to wade through 175+ posts to educate themselves on a somewhat esoteric topic. If you know one, please PM me contact info. [Please don't take my sarcasm personally; I really am deeply frustrated by how little help we have been able to mobilize from Mitsu over 4+ years of careful and deliberate work — I would not want you to tune out!!]
John
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gait
Explorer
not much help to you, it will be another few months but I'm hoping to hook into the k-line directly out of the ECU (rather than through canbus) to at least get the measurements and diagnostics off my FG. My first attempt (while in foreign parts) failed but I don't know if its the OBD/USB protocol converter or the k-line data. The ECU I have is Zexel which is a Bosch subsidiary. Its described in the manuals as Bosch ECU. I can't find any information on how much Zexel changed the k-line, if at all, for Mitsubishi.
Boost pressure and temperature combined are likely a proxy for mass air flow. That plus accelerator position maps to fuel input. From what I can tell there's not much feedback involved apart from through the driver (accelerator position). For example, no measurement of fuel flow, and on my vehicle no measurement of fuel pressure. Mostly seems to be limits and cutouts.
When you get the pyrometer installed I'd be most interested if higher exhaust temperature leads to higher boost pressure as it would be counter to how feedback control in wastegate operation is described and my understanding of physics, the gas laws and feedback control. But I'll keep an open mind, prepared for a bit of cognitive dissonance, waiting to be proven wrong. One of those "show me the data" discussions.
From first principles again, does anyone know how fuel pump pressure is regulated. And how to test it?
Boost pressure and temperature combined are likely a proxy for mass air flow. That plus accelerator position maps to fuel input. From what I can tell there's not much feedback involved apart from through the driver (accelerator position). For example, no measurement of fuel flow, and on my vehicle no measurement of fuel pressure. Mostly seems to be limits and cutouts.
When you get the pyrometer installed I'd be most interested if higher exhaust temperature leads to higher boost pressure as it would be counter to how feedback control in wastegate operation is described and my understanding of physics, the gas laws and feedback control. But I'll keep an open mind, prepared for a bit of cognitive dissonance, waiting to be proven wrong. One of those "show me the data" discussions.
From first principles again, does anyone know how fuel pump pressure is regulated. And how to test it?
Believe me, I think the same thing. All the times that Michael complained to Fuso about his malfunctioning AC and no one was able to figure out that it was the rubber flap in front of the condenser causing the problems with the FG AC doesn't say much about their service I'm afraid. Or maybe it says too much.
mog
Kodiak Buckaroo
John,
It was nice talking with you this morning and I'm sure we will be talking each other's ears off this Tuesday, but I thought I would post this to the portal so others could chime-in.
For your travels I believe you are concerned in order:
1. Reliability
2. Performance
You have been tracking down your ‘lack' of performance (#2) in case that is an indicator of lack of reliability (#1).
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I would say from your seat of the pant gauge and a few million runs (give or take) up and down your 5.5% hill that your truck's performance is close to specs if those specs exist. From the speeds and performance you have listed, your truck performs much better that my Fuso, which by the numbers has a better power to weight ratio. I would venture to say that by xx,xxx amount of trouble free driving for you, your tons of test, and a dyno run (no matter how well or not it was done), your truck is probably ‘healthy' (when you breakdown in Lower Nowereastan I will delete this post) . Or as best as anyone can tell. I'm not having worries about my Fuso, even thought it is being out performed by yours.
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So that brings us to ‘performance' (remember #2). Maybe you are off by 5-10% off 'advertised power'. You can either let that keep you up at nights, or look at it as my 'Expedition Engine has been derated slightly for more reliability'. That is what manufactures do. Derate an engine for difference uses. Just as you would not super-chip your engine to get an additional 30% power so you could blast down the highway at 80mph and perhaps sacrifice reliability, perhaps running a little ‘under-power' (if it is) might be a good thing. When you are in Lower Nowereastan, the fuel is subpart at high altitude and hot ambient air temperatures, it is better to to say have a ‘normal' EGT of 850* ‘climb' to 950* , then say your normal of EGT of 999* climb to 1200*.
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Maybe I'm being too glass-half-full (you are trained to figure that out), but I'd maybe add an EGT gauge and go expeditioning. Or maybe not, it might become like your added boost gauge and give you more worries.
It was nice talking with you this morning and I'm sure we will be talking each other's ears off this Tuesday, but I thought I would post this to the portal so others could chime-in.
For your travels I believe you are concerned in order:
1. Reliability
2. Performance
You have been tracking down your ‘lack' of performance (#2) in case that is an indicator of lack of reliability (#1).
-
I would say from your seat of the pant gauge and a few million runs (give or take) up and down your 5.5% hill that your truck's performance is close to specs if those specs exist. From the speeds and performance you have listed, your truck performs much better that my Fuso, which by the numbers has a better power to weight ratio. I would venture to say that by xx,xxx amount of trouble free driving for you, your tons of test, and a dyno run (no matter how well or not it was done), your truck is probably ‘healthy' (when you breakdown in Lower Nowereastan I will delete this post) . Or as best as anyone can tell. I'm not having worries about my Fuso, even thought it is being out performed by yours.
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So that brings us to ‘performance' (remember #2). Maybe you are off by 5-10% off 'advertised power'. You can either let that keep you up at nights, or look at it as my 'Expedition Engine has been derated slightly for more reliability'. That is what manufactures do. Derate an engine for difference uses. Just as you would not super-chip your engine to get an additional 30% power so you could blast down the highway at 80mph and perhaps sacrifice reliability, perhaps running a little ‘under-power' (if it is) might be a good thing. When you are in Lower Nowereastan, the fuel is subpart at high altitude and hot ambient air temperatures, it is better to to say have a ‘normal' EGT of 850* ‘climb' to 950* , then say your normal of EGT of 999* climb to 1200*.
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Maybe I'm being too glass-half-full (you are trained to figure that out), but I'd maybe add an EGT gauge and go expeditioning. Or maybe not, it might become like your added boost gauge and give you more worries.
JRhetts
Adventurer
John,...So that brings us to ‘performance' (remember #2). Maybe you are off by 5-10% off 'advertised power'. You can either let that keep you up at nights, or look at it as my 'Expedition Engine has been derated slightly for more reliability'. ....
Maybe I'm being too glass-half-full ...., but I'd maybe add an EGT gauge and go expeditioning. Or maybe not, it might become like your added boost gauge and give you more worries.
BRILLIANT!
I think you should have been [or maybe you were] a psychologist. You have managed to reflect the patient's problem right back to him, all the while avoiding any commitment to an opinion on how to resolve it. "Just let 'em stew in their own juices", I always said.:ylsmoke:
More seriously, I have recognized all along that my power may be just fine. It has been the nagging wonder if there is a canary I should be paying attention to that has driven this quest. I am fully aware that if in even a full day of driving I climbed many hills at 10 mph faster, I'd only get to wherever I decided to stop for the night 5-10 minutes sooner. And I know full well I'm not lacking any power in low range when I pull through stream beds or sand washes. We go!
I've got an idea for a non-intrusive EGT probe I want to run by you on Tues/Wed. I'm looking forward to seeing you then.
John
JRhetts
Adventurer
I will be VERY INTERESTED in what you find about how to tap into the data flow. Please keep me up with what you do/find! What year/model is yours?
That is how I have come to see my engine- mostly limits and cutouts. For example, in section “13E: Electronically Controlled Fuel System”, there is a table of 37 elements and their ‘function/operation’. 35 elements are described as ‘detecting’, ‘sensing’, ‘indicating’, etc. Two are described as ‘controlling’:
injectors: control of fuel injelction rate, fuel injection quantity, and fuel injection timing
suction control valve: control of fuel injection pressure
However, I find nothing about any feedback to the ECU on whether the targets for the injectors' performance is being met. suction control valve: control of fuel injection pressure
I am going to look more closely at the suction control valve; I simply do not understand it yet. It may be the key to whether I could adjust my fuel:air ratio to try for hotter combustion and more power. A chip to interact with the ECU is another way. On another thread [http://www.expeditionportal.com/forum/threads/117199-Performance-Chip], westyss reports some promising results on an FG. Know anything about it?
gait, I have been thinking about this a lot!
charlieaarons’ earlier comment [“If your preturbo temp is say only 900F instead of 1150-1200F UNDER FULL LOAD you need to have the ECU worked on to increase fuel delivery. If that is the case, your turbo boost will "automatically" increase to 22 psi since the hotter exhaust flowing thru the turbine will increase compressor rpm"] sounds so logical and clear, but I keep having a nagging thought: “…but, according to Boyle’s Law and the negative/feedback control design of my waste gate, with more heat my waste gate will open and dump anything higher than 18psig.” I gather this is what you have been thinking, right?
So, I too have taken a “show me the data” position; it’s just that I have to create the data, and have not quite figured out how to do that [manipulate fuel flow in this electronically-controlled system].
As indicated above, I am going to look more closely at the suction control valve. Would an electronic copy of the Service manual for 2005-07 FE/FG and FK/FM models be of use to you?
It’s too bad that we can’t just rotate the fuel pump a few degrees like it used to be possible! But I guess you can argue that today’s engines overall are “better”– at least in some ways.
charlieaarons
Explorer
Re my previous comment
Do you know FOR SURE that the wastegate is set at 18 psi?
Or is it closed and just getting to only 18 psi because the exhaust flow isn't that hot?
If the former is true (wastegate opening early) and fuel flow is nominal, then EGTs should be HIGH
If the latter is true and the wastegate is truly set at 22psi then EGTs should be LOW.
Charlie
Do you know FOR SURE that the wastegate is set at 18 psi?
Or is it closed and just getting to only 18 psi because the exhaust flow isn't that hot?
If the former is true (wastegate opening early) and fuel flow is nominal, then EGTs should be HIGH
If the latter is true and the wastegate is truly set at 22psi then EGTs should be LOW.
Charlie
JRhetts
Adventurer
Charlie
I really appreciate your contributions. The best answer I can give is to spell out what I am sure I do know: the WG CAN be set to limit at 18 psig. To even address Quest#2, I would need an EGT sensor, and I would need to find a way to add more fuel/heat. I do not have either [yet.] But more fundamentally – given the way the system works – I cannot answer your second question as an "or" question.
a. Regarding boost pressure, measured as psig, there appear to be (2) distinct ‘set’ or limit points defined by independent parts of the overall system.
b. One limit is defined by the ECU. It sets fault codes when the boost pressure sensor signals ≥ ±23.5 psig, and it puts the overall system into ‘limp’ mode.
c. The ECU may use additional data than only from the boost pressure sensor; the system also includes sensors for boost air temperature, atmospheric pressure, coolant temperature, common rail pressure, etc. I have no access to the ECU code, so I cannot determine with certainty what it uses.
d. The second limit is defined by the mechanical construction of the waste gate actuator [WGA], by the combination of the diaphragm stiffness on the inlet side and the spring resistance on the output side of the sealed WGA body.
e. I am quite certain that there is no ECU control over the WGA; and the WGA has as input only air pressure from the output (compressor) side of the turbocharger.
f. While the ECU defines a constant limit, the WGA has a range of possible limits. In its ‘unadjusted’ [factory] state, the WGA opens the WGValve so as to limit boost at 18psig. In ‘disabled’ state [all turbo boost blocked as input], the WGA does not operate at all, the boost pressure will rise to ± 23 psig and the ECU sets a fault code. The WGA can also be ‘adjusted’ [by creating a pressure differential relative to the intake manifold pressure]; it will then open at any pressure between 18 and 22 psig. For example, when the WGA is ‘adjusted’ to open he WGValve and limit at a max of 22psig, the engine operates continuously up to 22 psig and the ECU does not set fault codes. Hill climbing performance was no better at 22 than at 18 psig.
So, I can't really answer your second question as an “or”. And, I can't tell whether the exhaust gas is or is not getting as hot as it could. If I understand the system, even if I added more heat, I'd have to adjust the WGA to get more boost at the intake manifold: Without adjusting the WGA, the additional heat/pressure from more fuel would simply be dumped when pressure exceeded 18psig.
It seems to me that for me to move beyond my present state, I will have to do two things: add an EGT sensor AND find a way to add some variable amount of fuel.
[I am exploringwhether I could: i) ‘adjust’ the operation of the Suction Control Valve, ii) add a chip, and/or iii) limit EGR to increase combustion temp.]
With both EGT and more fuel, I could see if boost and/or temperature went up as a function of fuel. Furthermore, I could investigate changes in performance on the local 5.5% grade. However, if I cannot find a way to vary the amount of fuel injected, then no further steps are really worth a darn. I might find monitoring EGT interesting or even valuable on a hot summer day while climbing hills, but if I can’t manipulate fuel then I have no means to affect either heat-to-boost or performance.
Do you read things the same way? Others?
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