Power Problem with FM260

[kerry]

That dyno place sucked. I'd write a letter to them and complain about the service you got given what was promised. I would especially complain about their definition of a 23% power loss as slightly low. I would also send a similar letter to Fuso headquarters complaining about the response.

I don't know enough about computerized diesels to make an intelligent comment. But like you, my gut says a fuel problem given the lack of improvement between the boost pressures.

By the way, what did they charge you for the dyno run? Around here, a truck run on the dyno for emissions is $75.

 

[Ruderacing]

I agree with Kerry, what a pathetic dyno run! I would guess they actually don't know how to do it and are too embarrassed to admit it. They should have been able to manually measure things like boost press/temp, fuel rail pressure, exhaust temp, air fuel ratio etc. Generally speaking with those type of parameters being measured with rpm and torque you can see where the power loss is coming from.
That 195 intake temp is pretty high does it have a charged air cooler? What is the current AFR?

 

[JRhetts]

...That 195 intake temp is pretty high does it have a charged air cooler? What is the current AFR?

While I cannot be sure, I think the 195°F temp was engine coolant temp. There is no sensor on intake air temp.

And yes, it does have a CAC.

I have no idea what the AFR is; I had wanted them to measure that to begin diagnosing the possibility of fuel side issues.

 

[JRhetts]

You can buy Chinese cones of the MUT III readers online, but they are about $600. As far as I know, these are backwardly compatible to MUT II.

I have a contact here at home who designs and builds chips for boosting performance on Porches and BMWs. He also has a Mitsu Montero he'd like to reprogram, so we have discussed getting a MUT-II/III unit. His experience is that the quality of the stuff available on ebay is so sketchy that he has so far not been willing to give me a GO to get one. I would probably do so if I could have it on my travels to do a really precise job of diagnosing problems. But if they are actually junk, then I don't need [another] $600-800 boat anchor.

Do you or anyone you know well have any experience with one of the Chinese knockoffs?

P.S. I remain very appreciative of your sending me the Nordlock washers. They are great.

 

[JRhetts]

HP & Torque curves in Post #135

It is my impression that both the HP and the Torque curves may be shaped 'wrong' - should the Torque curve have its peak lower [at closer to the ~1400 rated max point] and then NOT drop off so precipitously at higher RPMs? And should the HP curve be more like an ascending curve from low RPM to a high at its rated 2600 RPM and then drop moderately?

Maybe this is just silly on my part? Maybe its a function of my axis scales, but they don't look like I'd expect them to. Not at all sure why!

John

 

[Amesz00]

My conclusion [very counterintuitive]: higher turbo boost at the intake manifold does NOT produce better performance. If anything, there is slightly reduced performance under the higher boost condition.
Again, I find myself wondering about a fuel issue.

its not counter-intuitive at all. 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

 

[Ruderacing]

This is from my FG dyno run taken a couple of years ago.

 

[kerry]

The 77% number is unclear to me. Are they saying they measured 77% of the rated horsepower at the wheels? If so, the engine is not down 23% in power because there is horsepower loss in the drivetrain. Or are they saying that they measured 77% of what you would expect to find at the wheels for an engine of your horsepower rating? If it's the latter, then it's a more serious problem than if it's the former.

 

[charlieaarons]

Like I've been saying repetitively, you need a pyrometer. That simple measurement will tell you if you are getting enough fuel. 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.
This whole thing may simply be insufficient max fuel delivery.

Charlie

 

[Overland Hadley]

The 77% number is unclear to me. Are they saying they measured 77% of the rated horsepower at the wheels? If so, the engine is not down 23% in power because there is horsepower loss in the drivetrain. Or are they saying that they measured 77% of what you would expect to find at the wheels for an engine of your horsepower rating? If it's the latter, then it's a more serious problem than if it's the former.

Good point.

 

[Overland Hadley]

Like I've been saying repetitively, you need a pyrometer. That simple measurement will tell you if you are getting enough fuel. 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.
This whole thing may simply be insufficient max fuel delivery.

Charlie

Charlie,

Is there a chance that it could be something mechanical (eg fuel filter, fuel pump...) instead of an ECU problem?

Sorry, I do not know, that is why I am asking.

 

[charlieaarons]

It sounds like this has been fairly constant since new, and filter or pump problems would start with fuel starvation at full load and then worsen with time.

Charlie

 

[mog]

First, I agree you did not receive a valid dyno run and engine parameters check.
A single dyno run, without all the ‘goods’ being monitored was pretty much a waste of time.
-
I could be wrong, but I’ll throws this out so the smart guys can correct it if necessary but a dyno measures ‘moment of force’, what we call torque, not horsepower. Horsepower is unit of measure for power, in this case torque. So they measure torque and calculate horsepower. It is ‘strange’ they give it to you the opposite.
If the measured power (HP and torque in your case?) is 23% less then ‘advertised’, what is Mitsubishi’s official drivetrain parasitic loss percent?
BIG question there. If it is 20% and you are only down 2-3%, then cool-beans, but if it is 10% and you are down 13%, then no-go. I’d sure like to know the official parasitic percent.

I agree with Kerry, what a pathetic dyno run! I would guess they actually don't know how to do it and are too embarrassed to admit it. They should have been able to manually measure things like boost press/temp, fuel rail pressure, exhaust temp, air fuel ratio etc. Generally speaking with those type of parameters being measured with rpm and torque you can see where the power loss is coming from.

A BIG +1 To that. Is the ‘excuse’ that the MUTT could not sent that data, or ?
-
It is interesting that your FM shows 77% of rated HP (188 vs 243) and Ruderacing’s dyno on his FE/FG shows 58% (84 vs 145).

 

[Overland Hadley]

It sounds like this has been fairly constant since new, and filter or pump problems would start with fuel starvation at full load and then worsen with time.

Charlie

Thanks for the explanation, makes good sense.

 

[JRhetts]

EGT - I think I finally get it

Like I've been saying repetitively, you need a pyrometer. That simple measurement will tell you if you are getting enough fuel. 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.
This whole thing may simply be insufficient max fuel delivery. Charlie

Charlie

I am not sure if you have experienced this in your encounters with human nature, but I sure have: How a comment is received is sometimes crucially dependent on how it is put, as well as the state of 'evolution' of the receiver.

I have been reading and trying to make sense of your [and others'] repeated points about a pyrometer and EGT. Perhaps I have evolved, maybe not. But the quote above came through crystal clear — I now get it. Over the past 4 weeks I have tried to understand what and how I could get useful diagnostic information from a pyrometer [this on top of the fact hat I am an experienced airplane pilot who is used to monitoring and adjusting for EGT.] Who knows why I did not 'get it' in this context until now, but what you said above makes it VERY clear, and for that I genuinely thank you. No accounting for human nature, eh?

John