Cummins ISX has FSS Derate [Archive] - TheDieselGarage.com

: Cummins ISX has FSS Derate


junebug
09-01-2010, 09:13 AM
I have a 2001 ISX CM 570. It has a stall at full throttle in every gear above 6. I notice it mainly in top gear around 1350-1400 rpm thru 1650 rpm. I did an Insite log to see what was going on. The user fueling state shows both an AFC Derate and a FSS Derate. I think the AFC is due to boost pressure being low(the boost sensor looks like it may be sticking), but I have no idea what causes the FSS Derate. The FSS Derate is the one causing the stall in top gear and the one I'm trying to diagnose and correct.

tc2
09-02-2010, 12:00 AM
the AFC derate is not enough boost and can be acceptable for up to 10 seconds at full load.. other than that needs looking at.

i can't find any info on an FSS derate.
there is a fuel system derate caused by an active fuel system fault, or a fueling high speed governor state which means the engine is at max. RPM.

try calling Cummins at 1-800-diesels and asking about that user fueling state. apparently there are about 80 user fueling states in total.

junebug
09-06-2010, 08:38 PM
I called Cummins and they said they have never seen an FSS derate. Thet also couldn't tell me what the abbreviation was for. I have also talked to a few Cummins techs who don't know anytging about it either. I have very little confidence in Cummins techs anyway.

pichu2
09-07-2010, 06:05 AM
I called Cummins and they said they have never seen an FSS derate. Thet also couldn't tell me what the abbreviation was for. I have also talked to a few Cummins techs who don't know anytging about it either. I have very little confidence in Cummins techs anyway.

is not FSS is FFS is you need chance fuel filter? FUEL FILTER SERVICE i check my manual:popcorn

junebug
09-07-2010, 06:15 AM
The fuel filters are new. Besides I can read and it is FSS not FFS. Its not a fault and there are no active or inactive codes being thrown. Its a user fueling state that happens during Maximum Fueling state.

mrdevildog
09-07-2010, 06:32 PM
whats your engine serial number?

junebug
09-07-2010, 08:06 PM
ESN 14012552. 2001 ISX CM570

tc2
09-07-2010, 11:41 PM
did you call the local Cummins dealer, or the 1-800 number?

the 1-800 number is for cummins corporate.That's the same number a tech calls for troubleshooting help once the engine is out of warranty. they should be able to look up all of the user fueling states or call engineering to find out.

junebug
09-08-2010, 12:24 AM
I called Corporate first. They said they had never seen an FSS derated user fueling state. They also couldn't find any info on what the FSS abbreviation stands for. All of the distributors just want me to come in and see them for 102 an hour. They also say there needs to be an active code for a derate, but Insite says no codes either active or inactive.

tc2
09-08-2010, 01:25 AM
yeah I couldn't find any info on an FSS derate either.

And no, you don't need an active code for the derate. There are quite a few derates that do not set a code.

It might not hurt to get the ecm flashed to the latest version. At least you might wind up with a user fueling state that makes sense.

It looks like your ecm code should be N10184 that code is up to version 28 now. version 23 and 24 were supposed to fix a 'stumble' which might help you as well.

The ecm code can be found in insite in the features and parameters page in the first section.

junebug
09-08-2010, 01:44 AM
It is flashed to Feb 2010 setting. I think its N11245.13. Have tried 6 different ones with 2834 CPL. Always dies this stumble. Maybe I need a new ECM.

tc2
09-08-2010, 02:27 AM
It looks like your engine left the factory at 565 hp, 1850ft-lbs torque.

Have you tried flashing it back to that level and seeing if the problem remains?

I'm grasping at straws. Just wondering if the wrong file might be in there.

junebug
09-08-2010, 02:47 AM
Before this my problem was poor performance and terruble mileage. I had it reset to 565 and had same problems with 4.75 mpg 30.mph uphill. Changed CAC turbo actuators lift pump installed straight thru muffler FASS and got 0 improvement. Went to 600 still no power but 5.5 mpg. Have tried several 565 and 600 settings but nothing has fixed it. Stayed with best mpg.

CaterpillarWrench
09-08-2010, 11:07 AM
I have a 2001 ISX CM 570. It has a stall at full throttle in every gear above 6. I notice it mainly in top gear around 1350-1400 rpm thru 1650 rpm. I did an Insite log to see what was going on. The user fueling state shows both an AFC Derate and a FSS Derate. I think the AFC is due to boost pressure being low(the boost sensor looks like it may be sticking), but I have no idea what causes the FSS Derate. The FSS Derate is the one causing the stall in top gear and the one I'm trying to diagnose and correct.

I had a customer with a similar problem.In the higher gears you could feel the power kick in and out.The problem he had was with the speed sensor wires down at the sensor on the front of the crank.

CumminsISXpower
09-08-2010, 11:51 AM
sounds like either metering or timing actuators to me,dyno it,what does the boost do at this stumble?Does it smoke? I cant see a timing sensor only happen under a pull. Boost actuator solenoid?? take hose off of turbo and plug,then drive it? Just some ideas

junebug
09-08-2010, 02:29 PM
Both of those sound like possible causes I will check those things first and see what happens. It doesn't smoke and the boost only varies a bit but I think its from the derate. It will make 32 psi and the log shows same as my gauge.

CaterpillarWrench
09-08-2010, 05:48 PM
As far as the AFC derate,they all do that while the AFC is limiting fuel until the turbo catches up.My customer also noticed a drop in fuel mileage and a rough idle.

pichu2
09-09-2010, 03:43 AM
:fan i think there a chip burning inside the ecm it s the thing that calculates the air and the fuel i found this on the web:bang i thinks it outside are hands:slap:shrugs Referring now to FIG. 4, a block diagram is shown illustrating another alternate embodiment of A/F control logic block 45 in control circuit 42 of FIG. 1. A/F control logic block 45'' includes a fuel command function block 100'' receiving theengine speed signal (ES) from engine speed sensor 44 via signal path 46 as well as the requested torque value (RT). Fuel command function block 100'' is responsive to the engine speed signal on signal path 46 as well as the requested torque value (RT)to compute a fueling control signal (FC). Fuel command function block 100'' may include any number of mapping functions, equations, graphs, tables, or any other techniques known to those skilled in the art to compute the fueling control signal. Thefueling control signal, FC, is then provided on signal path 74 by fuel command function block 100'' to supply fuel to engine 12.

A/F control logic block 45'' further includes a lambda command function 106'' receiving the engine speed signal (ES) from engine speed sensor 44 via signal path 46 as well as the requested torque value (RT) and computing a desired air-to-fuelratio value (DA/F). To compute a desired air-to-fuel ratio value (DA/F), lambda command function block 106'' further includes a lambda steady-state control function block 200'' and a lambda transient control function block 204''. Lambda steady-statecontrol function block 200'' receives and is responsive to the engine speed signal on signal path 46 as well as the requested torque value (RT) to produce an air-to-fuel steady-state value (A/FSS). Lambda steady-state control function block 200'' mayinclude any number of mapping functions, equations, graphs, tables, or any other techniques known to those skilled in the art to compute the air-to-fuel steady state value (A/FSS). Similarly, lambda transient control function block 204'' receives and isresponsive to the engine speed signal on signal path 46 as well as the requested torque value (RT) to produce an air-to-fuel transient value (A/FT). Lambda transient control function block 204'' may include any number of mapping functions, equations,graphs, tables, or any other techniques known to those skilled in the art to compute the air-to-fuel transient value (A/FT). Lambda control function 106'' further includes a lambda control interpolation block 208'' receiving the air-to-fuel steady-statevalue (A/FSS) as well as the air-to-fuel transient value (A/FT). Lambda control interpolation block 208'' is responsive to the air-to-fuel steady state value (A/FSS) as well as the air-to-fuel transient value (A/FT) to compute the desired air-to-fuelratio value (DA/F). control interpolation block 208'' may include any number of mapping functions, equations, graphs, tables, or any other techniques known to those skilled in the art to compute the desired air-to-fuel ratio value (DA/F). In oneembodiment, the lambda control interpolation block 208'' may produce the desired air-to-fuel ratio value (DA/F) as a function of the following equation: DA/F=α*(A/FSS) (1-α)*(A/FT), where α takes a value between [0 1].

A/F control logic block 45'' further includes first arithmetic block 110'' having an addition input receiving the desired air-to-fuel ratio value (DA/F) from lambda control function block 106'', and a subtraction input receiving the lambda signalfrom lambda sensor 80 via signal path 82. First arithmetic block 110'', which may be but is not limited to a standard adder and subtractor, an arithmetic logic unit, or any other means known to those skilled in the art, computes first error value (FE)as the difference between the desired air-to-fuel ratio value (DA/F) and the lambda signal via signal path 82. The first arithmetic block calculates the error between the desired air-to-fuel ratio which should be emitted from the exhaust of the engineand the actual air-to-fuel ratio being emitted from the exhaust of the engine in the feedback loop of the system. +/- this is the answer:read:damnit:shrugs:shrugs:shrugs

mrdevildog
09-09-2010, 01:04 PM
junebug, tc2 has a good ideal, not sure if you will be able to flash back or not, if you can then i would start there, see what the performance is, if it sucks then start with the basic checks, air inlet and fuel pressure. i would monitor fuel pressure while driving and make sure its good. Ive seen some of the cm 570's have a long hex shaped fitting intalled on the inlet to the ifsm that has a metal screen installed, it gets clogged with debris and causes weid issues.

junebug
09-10-2010, 02:29 AM
I have tried the original setting as well as many others, but none of them fix the problem. Performance doesn't change with any of the settings. That's one of the reasons why I think its something that can be fixed. I have checked/cleaned the screen you're talking about and it hasn't really ever gotten that dirty.

Pichu2 You may have the answer, but I don't really know how to read all of that. I'm sure it's over my paygrade.

CaterpillarWrench Did the ECM show erratic readings while the dropoff was happening? None of the numbers look out of place while driving it or on the logs that I have done with Insite.

mrdevildog The fuel pressure stays around 290 during the derate and stall. That was my first guess.

Where is a good Cummins shop to take this to? I think I am going to have to break down and have them look at it. I have been to a few, and I'm not going back to them so if anyone knows a really good shop that would help too.

junebug
09-10-2010, 02:53 AM
I tried posting a copy of the excel file of the log, but it's too big. If anyone wants to look at it let me know maybe I can email it.

pichu2
09-10-2010, 03:53 AM
:readI have seen your problem.(because i have a isx too:D) but i think,:shrugs but im not sure. the problem might be in the barometric sensor. this sensor is in the main hardener of the ecm. its flat sensor an has 3 wires. but if water, oil dirt+(2001 9 year old) get on it, and this sensor has a little hole of air read ambient, if the water or hole plugged the sensor act bad. its a possibility that when you or someone washed the motor with a water pressure could have pluged up that hole. if u have laptop(insite) u need to read 20.6hg or less i believe. that for lower than 10,000 feet alt. this makes the ecm act dumb and all sensors:popcorn and derated afc

junebug
09-10-2010, 04:23 AM
Where is this sensor because my ambient air temp reads 5 all the time. I asked cummins they said it didn't matter. Barometric is correct, but not ambient air and if they're on the same sensor I need to change it.

pichu2
09-10-2010, 07:49 AM
Where is this sensor because my ambient air temp reads 5 all the time. I asked cummins they said it didn't matter. Barometric is correct, but not ambient air and if they're on the same sensor I need to change it.

;)junebug Its mounted on the main harness to the ecm, left side rear lower side of engine, it is a flat sensor, 3 wire plug , should have a sensing pin hole in it ,when you check(running) NO less than 20.6 hg :thumbsup this is under 10,000'elevation

junebug
09-10-2010, 05:02 PM
Ok the log shows ambient air pressure at 29.5, but the ambient air temp is 5 all the time. I will change this sensor this weekend and see what happens. I will also try some of the other ideas and see what it does as well. I'll let you all know around Wed. what the results are.

tc2
09-10-2010, 11:27 PM
The ambient air TEMP sensor is an optional sensor that is only used with the Icon idle control system. The only effect it will have is to override the idle shutdown if it's cold out
If you try sending your log file in a PM i will have a look at it.

the ambient air PRESSURE sensor is usually built in to the ecm.

junebug
09-11-2010, 01:20 AM
Thanks to tc2 I realized I could ZIP this log and post it. Here it is for all to see.

tc2
09-11-2010, 01:43 AM
thx. will get back to you later this weekend.

tc2
09-11-2010, 03:04 AM
does your engine have fault code 259 logged?

junebug
09-11-2010, 03:55 AM
No there are no codes active or inactive. Do u think it should?

tc2
09-11-2010, 04:49 AM
I think your engine has a Fuel Shutdown Solenoid derate.

When the engine shuts down, the injectors keep cycling after the fuel solenoid is shut off. If the pressure doesn't drop the way the ecm thinks it should, it is supposed to set a fault code 259, AND impose a torque derate when the engine starts back up. This derate will last until the engine shuts down and sees fuel pressure drop the way it wants. This could be many drive cycles or forever, if nothing gets fixed.

I believe the derate is to keep the engine from running away in certain circumstances, although that is not made clear.

If I am correct, I think there are 2 possibilities :
1. your ecm is imagining things and setting the derate without a problem actually being there. This would require ecm replacement, though I suggest you borrow a known good ecm and confirm this before buying one.

2. There is an actual problem with the solenoid, it's related parts, or the fuel psi sensor, and the ecm is not logging the code properly. I suppose you could replace the ecm to try and fix the failure to log the code, but I don't see a point if everything else is working ok. This could also be a quirk of the software that no one has come across before.

Either way, I suggest you follow the fault code tree for code 259 (Fuel shutoff solenoid problem ) and see if that leads you anywhere. You should be able to access the fault overview and fault tree from the insite help menu. If you read the fault overview, I think you'll agree I'm on to something.

CumminsISXpower
09-11-2010, 04:55 AM
I used the 259 TS today dont use the help TS, use Quickserves!Wrong info!!I told cummins about it today!!

junebug
09-11-2010, 05:00 AM
I will definitely look into this possibility. I would tend to think that this would be a constant derate. The log and symptoms only show a derate while at full throttle. The FSS could very well mean Fuel Shutoff Solenoid tho.

tc2
09-11-2010, 05:08 AM
The chart says it will have a torque derate, not a throttle or speed derate.
A torque derate would only affect operation at close to maximum fuel.. full load, full throttle type operation.
If you did another log that also included %torque, that might help to show it better.


I will definitely look into this possibility. I would tend to think that this would be a constant derate. The log and symptoms only show a derate while at full throttle. The FSS could very well mean Fuel Shutoff Solenoid tho.

junebug
09-11-2010, 05:20 AM
Ok this is very helpful. The log was of all paramaters and %torque wasn't on it. I don't know if I can monitor %torque? I won't be home until tomorrow night so it will be Saturday before I will get to check this out. I don't like to check too many things on the road because road services and tow bills are expensive.

tc2
09-11-2010, 08:25 PM
If you monitored all parameters, I guess you can't show %torque. It depends on the particular model, calibration, etc.

junebug
09-15-2010, 05:57 PM
I checked everything that I could and found nothing. I'm taking it to a Cummins shop tomorrow to dyno and hopefully diagnose this derate. I'll post what they think or do to fix it.

junebug
09-17-2010, 01:05 AM
Well I went to a Cummins shop today. We road tested it while monitoring specs with Insite. The tech didn't know why it would go into a derate without an active code. I really didn't learn anything new while I was there (pretty much what I expected). I did however buy a fuel shutoff solenoid and an ambient air pressure sensor.

tc2 you were probably the closest to nailing this. I got the old solenoid off and it had been installed incorrectly. The spacer has 2 o-rings that seal it off, but the spacer was turned around the wrong way so that the groove of the spacer faced the groove of the IFSM. I guess the o-ring had flattened out enough to allow seepage and cause the derate. I replaced the valves o-rings and solenoid, took off, and it was like a different truck. I think I will replace the ambient air pressure sensor anyway as it is giving some erratic readings (although they are still within spec).

Thanks to everyone for your help solving this. I don't know if I would have ever thought of that solenoid.

tc2
09-19-2010, 02:59 AM
glad you got it worked out.

legend10
09-19-2010, 06:13 PM
So by fixing the fuel shutoff soleniod it works fine?

junebug
09-19-2010, 08:45 PM
Yeah it seems to have fixed the problem. I haven't been able to run another log on it to see if it's still derating, but it pulls like it should and doesn't stall like it was doing.

maniaq
10-29-2011, 05:08 PM
hi everybody, i'm new on this forum,
i'm working in a volvo dealer in quebec canada since 15 years
i have a fss derate and nobody can help me on that, tech assist cummins are not able to help on that derate, the power seem to kick in and out at full load between 1400 and 1600 rpm. i monitor all parameters and sensors. everything is ok, fuel pressure is 276 lbs bosst level is 36 lbs. fuel system is check and recheck, fuel shut off is new.( the problem was there before and after the fuel shut off change). i install a spare ecm, the problem still occur. no active or inactive fault code.

any suggestion??
thanks you

junebug
11-02-2011, 03:50 PM
I eventually found that it wasn't the fuel sshutoff. It was the crank position sensor. It had gotten dirt and oil in it and wasn't getting a good contact so the reading was off. It wwont throw a code since it is still getting aa reading, it is just inaccurate. Try checking the sensor connection for dirt. If its dirty clean it out and run it to see if the derate still occurs. If so check the camshaft position sensor for dirt because these two work together qnd if one is off it will cause the same derate. It is not necessary to replace the sensors just keep them clean and clear any faults out both active and inactive. Let me know if it helped you

maniaq
11-04-2011, 01:06 AM
last week i though that maybe i could have a problem with timing sensor, but both sensor aren't old( maybe 6 month and i change the wire from sensor to ecm. that why i did not spend much time on timing sensor. but timing sensor will not cause a fss derate. and why timing can't not affect only on full load? i will try to investigate timing at the next cutomer visit.

thanks you and i will give you news