Power Problem with FM260

[gait]

just a thought from recent experiences with FG,

atmospheric pressure at 1,100m (Bend, Or) is about 90kPa, which is about 10% lower than sea level (100 kPa). I don't know about relative humidity or ambient temperature at Bend. All three have the potential to effect turbo boost.

I don't know what conditions the engine specification relates to. I don't know how the control scheme compensates or over what range of atmospheric conditions.

I do know that at about 3,800m (about 65kPa) my FG engine malfunction light is on at some rpm and load conditions due to low turbo boost and at 5,000m (55kPa) more often. Unfortunately I don't know the boost measurements or at what level the ECU records a problem.

Without measurements its difficult for me to know but it appeared that fuller fuel tank with better fuel delivery, fuel filter, and clean air filter provided some improvement. I didn't attempt tuning the engine for higher altitude.

With two fuel tanks I know there is a minor niggling problem with delivery through the longer pipe from one tank that occasionally prevents running the tank to empty due to fuel starvation. A resolved related problem was a small air leak in the bowl of the water seperater. I replaced all pipes, one day I'll add an extra electrical lift pump.

Hopefully there may be some ideas in the above.

 

[JRhetts]

Gentlemen

THANK YOU VERY MUCH FOR TAKING THE TIME TO MAKE CONSTRUCTIVE POINTS AND RAISE VALID QUESTIONS. You've given me a bunch of stuff to follow up on, some of which will be rechecking things that were checked once before but warrant doing so again. And some points, if they prove true, will be very embarrassing [rags or bad filters, etc] but which could well be the culprit,.... if as Mog questions there really is one.

On the point about fleet data, I have only two data points. One is the sister vehicle, which does NOT seem to suffer the same lack of power as mine, even right out of the chute when Darrin Fink was driving both of them in turn. Second, the Mitsu service manager told me he services a whole bunch of FM260s, and test drives them up the same hills we ran with his diagnostic computer running. His impression is that mine certainly seemed less powered compared to others, but that certainly ain't empirical/quantitative either.

Please keep the suggestions flowing, and I will get back to you all as I work thru the list.

Again, thanks!! John

 

[kerry]

Could it be a leaking wastegate?

 

[charlieaarons]

Do you have a pyrometer as well as a boost gauge?
If EGT is insufficient, not enough fuel.
If EGT is too high, multiple causes including insufficient air and restricted exhaust.

Charlie

 

[Amesz00]

whatcharterboat
Maybe Andrew should check for octopus in the exhaust too if he wants to keep going through that deep water in his crewcab

haha yer very funny.. for your information thats exactly what the stack's for

John, (erm, other John..) one thing that would be an interesting comparison if you can do same on another truck with same engine (and rated output!) is have someone stick an air:fuel meter in the end of the exhaust, then run it at full load down the freeway or up a hill.. the measurement on its own from your rig doesnt mean much, but put against the same from another properly performing truck.. if your truck is leaner or even similar AFR (as it is getting less boost so less air) then you know it is getting much less fuel, and this could be the true source of your dramas. if it is richer, then its likely getting same fuel, but has less air to mix it with.
another thing to try would be (not on the same test though) unplugging the wastegate actuator line (+ block the feed from compressor, obviously this is pressurized) and see what it does.. dont worry it wont blow up, just keep an eye on the boost gauge and if it gets much above 30 then probly back off.. if it changes much, then maybe a manual boost controller in the line, adjust it to 22 or 24 or so. if its still down on power then its not the turbo.
just some ideas..

 

[jhrodd]

I have to say that those 'experiences' sound pretty baseline Fuso performance.
Your Uber-Fuso:
Weight.......HP (spec)..................Torque (spec)
23,300.......243 {96 lbs per HP}....516 {45 lbs per lb/ft}
My Fuso FG
Weight.......HP (spec)..................Torque (spec)
10,500......145 {72 lbs per HP}....275 {38 lbs per lb/ft}
No way can I even think of holding highway speeds on hills. Every hill is a downshift to 4th at least and long 5-6% grades bring the dreaded 3rd gear downshift.
Acceleration-to-pass, yup I did that once, we even took photos to prove it (it was a 'real' car, not a VW bus).
-
I fully agree you should be getting your rated boost and rated HP/Torque, but even if you get a true 18% direct increase with boost at 22psi, my very non-performance FG at the weights and HP/Tq listed above has an 18% advantage in HP to weight, and 32% Tq to weight, and it sxxxx in the road performance aspect.

My FE140 with auto transmission has 175 HP and 391 ft.lb's and at 12,000 lbs it's in the truck lane on 6% grades (35-40 mph). John's FM also has an automatic and hydraulic transmissions do use up some of your available power. I would be curious to know what his terminal speed is on a 6% grade. I had a Volvo with a 500 HP 1650 ft.lb. series 60 Detroit with 3.55 rear end that was an absolute slug through the gears, everybody left me behind at stop lights, but it pulled mountain grades at 50-55 mph with a 60K load I always thought there was something wrong with it but it hauled *** up the hills I had to slow down in the curves going up Cabbage in Eastern Oregon with a load on. My Kenworth with a 475 hp 1650 ft.lb. Cummins and 3.36 gears was a sport car in comparison but about 10 mph slower on the hills. My Cascadia with a 455 multi torque 1550/1750 and 3.42 gears was very quick off the line but pulled the big hills at about 30-35 mph @ 60K loaded weight. These trucks all had different automated mechanical transmissions which also had an effect on their power delivery. The Eaton Ultrashift in my Cascadia has dozens of different transmission programs available.

 

[mog]

My FE140 with auto transmission has 175 HP and 391 ft.lb's and at 12,000 lbs it's in the truck lane on 6% grades (35-40 mph).

That is right were I am at on 6% grades. If I can do them at 35-40 mph in 4th gear I’m happy, but the downshift to 3rd at 35 mph seems like defeat. My goal is to stay in 4th if possible. I’ve been looking into water/methanol or propane injection to use just on the hills to maintain 4th. It is a long-term project since I need to install an EGT (pyrometer) and boost gauge, prior to any add-ons. Thanks for the feedback, it is nice to know I am not alone in the slow lane on the hills.

 

[kerry]

I'm not sure of the exact grade percentage but I do end up in 3rd gear sometimes, although not often. It's usually 4th gear. I'm pushing 12k lbs. In the thread I linked a few months ago where forum member ?????? describes his experience with install a Fuso engine in a Land Cruiser, he found his wastegate was leaking and that solving that problem significantly improved his power. I've purchased a boost gauge ($16 Ebay) to check my boost to see how much boost I'm getting and whether or not it can be upped. I suppose wiring the wastegate shut and climbing a steep hill might also produce some useful info.

 

[JRhetts]

Dyno Test for basic diagnosis

Not sure if we ought – or not? – to move this to a new thread, e.g., "Diagnosing Power Problem on Fuso FM260". On the one hand that is what this whole topic is really about. On the other hand, we have a going conversation that is working for me, so I'm happy to continue here under "Engine Oil analysis" if people keep contributing.

As several contributors have suggested/opined, I cannot yet be sure that I actually have a problem. I have no objective measure that I am actually lacking power from my engine. All my "data" are impressionistic. Over 2 years ago I began trying to get a dyno test on the rig, but I hit dead ends everywhere I turned. But now...

jhrodd put me onto a shop in my general area that has a truck dyno. [In fact I talked to them about 2 years ago, but was not able to establish constructive communication at all. At any rate...] today I again talked with the service dept and indirectly with the shop foreman. Right out of the box they wanted to know whether my Allison 2400 automatic transmission can be set to hold – and NOT downshift – in a given gear, probably 4th [as near direct drive as possible]. They tell me that if the tranny decides to downshift during the test that this can cause significant damage to my transmission. I was not able to get an explanation for why that would be a problem. Their answer: "That's our experience."

Can anyone help confirm whether this would be a problem and perhaps why? It's probably straightforward, but I don't understand it yet.

At any rate, I am off to drive some hills in 4th gear. I know I can limit the upshifting to any gear [1-5], but I do NOT think I can limit downshifting when the tranny thinks it is time to do so. A road test should determine that. I am also going to call Allison.


LATER INFORMATION:
After calls to several Allison service shops, one distributor, and to Allison company headquarters – no one seems to know for sure whether the transmission can be locked out from downshifting.

Allison corporate was vague about whether a downshift occurring under load on a dyno could be 'destructive'. The tech I talked to made an analogy to skidding on ice and then encountering pavement; his description was: in a car, you'd get skidding, but in a heavy truck the friction on the wheels could be passed on to the tranny and do damage. In my mind, he seemed to be invoking or suggesting something like 'inertial shock' due to the resistance or load from the rollers on the dyne. My takeaway was that I can't be confident that I can safely do a dyno test on my rig.

Allison corporate tech then recommended I call one or more specific dealers for more detailed and expert information –– ?????don't they know their own trannies?

One dealer they recommended is one of the ones who told me a dyno run could be destructive in the first place, tho they could not explain why. Another is contacting 'an engineer' to call me back to explore this further.

 

[kerry]

In Colorado, I'm pretty sure that truck would have to be dyno'd for the emissions test. I'm guessing all FM's on the front range are routinely dyno'd for that purpose. The test requires running the truck at highway speeds. If they survive those emissions test it seems that other dyno tests would be ok. You could ask the Denver Fuso dealer about that.

 

[kerry]

This is probably not a helpful comment but I just read Mog's numbers and gave them some contemplation in light of how I feel about my FG's performance. My conclusion was that I wouldn't buy an FM given the lower hp/torq #'s per pound. I am happy with my FG but it is right on the edge. I've probably only passed a couple of vehicles on the highway in my years of ownership. I almost always drive it with my foot near the floor. What's the top speed on your FM? I top out around 68mph.

I've owned two seriously underpowered campers--both MB's. A 1985 307d class A with a 616 4 cylinder diesel and a 1985 409d with 5 cylinder diesel. Both 5 spds. Hence my satisfaction with my FG. The other group of people who would be happy with an FG would be people who have driven 60's VW vans. Apart from that, I think most US drivers would find my FG too underpowered for their liking.

 

[mog]

The other group of people who would be happy with an FG would be people who have driven 60's VW vans.

I used to have a '68 VW Kombi and even it's power to weight ratio beats my Fuso
:sombrero:


......................................Weight.......HP......... Torque
Fuso FM..........................23,300....... 243........ 516
...............pounds per......................95.88....... 45.16
Fuso pre-2005.................10,500....... 145........ 275
..............pounds per.........................72.41..... 38.18
Fuso pre-2005.................12,500........145........275
..............pounds per.........................86.21..... 45.45
Fuso 2005-2011..............12,500........147........ 347
..............pounds per........................ 85.03..... 36.02
1968 VW type 2..............3,600..........51......... 81
............. pounds per......................... 70.59..... 44.44
Earthroamer HD..............26,000........360....... 800
............. pounds per......................... 72.22..... 32.50
'02 F250 V10..................8,800..........310........ 425
............. pounds per......................... 28.39..... 20.71
MB 1017A......................21,500........ 168........ 383
............. pounds per......................... 127.98....56.14
UniCat IN7400................26,000........ 310........ 860
..............pounds per........................ 83.87..... 30.23

 

[kerry]

The different gearing in some of those vehicles makes a huge difference. For instance, the MB 1017A in the typical version probably has a top speed of around 53mph or so. It would be intolerable on the interstate but acceptable on roads with speed limits of 45mph.

 

[Flys Lo]

Ha, you guys complain. I had a 1988 Canter with a 8800kg GVM, was fitted with their 2.8l NA diesel and 5 speed stick. The non turbo version of the diesel fitted to the Pajero/Shogun and 71hp I think? Flat out, empty, with a tail wind it might do 65mph. Up a hill loaded to GVM it would regularly see second gear.

As for the OP's problem. Dyno wont show you anything that a hill doesn't already - unless you are fitting it up with sensors. The EGT guage suggestion is a good one. The thing with diesel engines is their sheer simplicity. A lack of power means either a fuel or an air issue, and one of them is lacking (or your injection timing is off), an EGT sensor can help you.
If your truck isn't blowing black smoke, I always suspect a blocked injector.

...or propane injection

I wouldn't...

 

[JRhetts]

Chassis Dynamometer Test Scheduled- finally

I'm almost thinking perseverance pays off: After calls to more than a half-dozen shops that claim to do dyno tests, not one represented that they actually did tests on automatic transmission trucks or RVs. Until...

An outfit in Centralia, WA named BrazelsRV says they have done literally thousands of chassis dyno tests on automatic transmission RVs using a water-brake dynamometer. The tech who actually does the tests said: “We will need you to max out rpms up to the governed max limit in your transmission's 1:1 gear ratio [in my case 4th gear]. We add resistance via the rollers on the dyno until your transmission tries to shift into the next lower gear, just as if you were climbing a hill and the tranny determined it needed to downshift. This gives us a HP and torque number; we do this 3-4 more times to get an average. This averaged number is what we give you.”

He says that this process has never resulted in a destructive effect.

In addition, he tells me that I should expect a roughly 15% loss through the powertrain, which makes sense to me. Anyone have a different coefficient?

I am going for this test late next week, and I will report back when I get the results.

If I get a HP result no lower than 205, and a torque number no lower than 434 ft.lb., I will be done with this. I can accept that my engine certainly is not a powerhouse, esp. compared to other more modern and higher-tweeked ones. All I have ever wanted is to be sure that there is no significantly-undue malfunction as I putter up hills.