Does my engine need a rebuild?

Nautamaran

2004 140” HRC 2500 (Crewed)
Would anyone be able to give me a baseline for MAF and TCM torque at full throttle around 2-3k RPMs?
Here's a random log entry from one of my Nautabox tests... I've attached the complete file below.
(save it as a .csv file and import into your favourite spreadsheet program...)
Sorry I don't have a recent log file to share... the boxes have all gone out the door so I don't have one handy.

=============
55 F ambient air temp (intake temp at startup)
12.8 psi barometric pressure (ecm sensor; Calgary is 3500 feet above sea level)
185 F coolant temp

2800 RPM
5th gear; "locked" TCC (~60 rpm slip to soak up power pulses)
99% LOD
32.3 psi MAP (intake manifold pressure; full 20psi boost)

221 foot pounds engine torque (into torque converter)
130 grams per second MAF
30% EGR (% of pulse width modulation)
22,658 psi FRP (typical fuel rail pressure for high RPMs)

==================

Later during the same drive:

1800 RPM
5th gear; "locked" TCC
92% LOD
28.5 psi MAP

203 ft lbs torque
72 g/sec MAF
23% EGR pwm
17,686 psi FRP

===================

Note that these torques are calculated by the ECM and reported by TCM as Engine Torque.
I need to look it up, but I think our OM647 is rated at 240 foot pounds?
Others might chime in with better data selections.

-dave
 

Attachments

Nautamaran

2004 140” HRC 2500 (Crewed)
Same data file from Sept 22, 2020, pared down and sorted by LOD and Engine Torque

TIMESpeed
(mph)
LOD
%
Coolant
Temp
(F)
Intake Air
Pressure
(psi)
MAP
(psi)
Turbo
%pwm
(0=full)
MAF
(g/sec)
Fuel RP
(psi)
EGR
(%pwm)
Engine
Torque
(ft-lbs)
Converted
Torq output
(ft-lbs)
Engine
RPM
Actual
Gear
13:32:582599177.3512.87632.85765125.032224329.82229.39229.3925892nd
13:04:486199161.1512.89129.4787496.022020336.5222.02222.0223255th
13:08:037399185.4512.78932.27761129.972265829.89221.28221.2827935th
13:04:233699152.5112.90531.27665118.052077728.69217.59217.5924323rd
13:06:186199181.3112.83232.16162139.44227225.29215.38215.3828284th
13:06:135099180.4112.81833.82859158.412300929.47209.48209.4832533rd
13:04:295399153.0512.80331.92954150.752310434.73205.05205.0534103rd
13:42:283399181.8512.97721.7799546.381465822.98170.39170.3915674th
13:39:232897182.7512.93429.9867487.141829220.86234.56234.5619063rd
13:42:343494182.7512.93427.1297762.191685814.38222.76222.7616104th
13:42:383494183.6512.93426.9847761.521714515.55220.54220.5416214th
13:07:596892185.0912.81831.68269115.03212565.29204.32204.3225945th
13:02:474792134.8712.93428.5367472.641768623.24202.84202.8418235th
13:03:49192146.5712.99217.1398654.83127469.98127.6183.6616531st
12:56:5349159.8112.93418.1989354.331335210122.44154.916001st
13:38:394890183.1112.93426.9127675.64178455.29216.85216.8518575th
13:34:275190185.9912.91929.4496580.361577323.53200.63200.6319955th
13:34:084090182.2112.84731.04468115.552138332.96199.89199.8926183rd
13:02:444490133.7912.94828.1598269.971698519.64196.2196.217405th
 

Nautamaran

2004 140” HRC 2500 (Crewed)
Would anyone be able to give me a baseline for MAF and TCM torque at full throttle around 2-3k RPMs?
Following up on this request, I was watching my dash box today (first prototype so no data logged…) and I could get 300 foot pounds indicated during full-on pedal-to-the-floor launches, with the MAF reading up around 160 g/sec.

The charts vary, but I found web pages claiming that the om647 is rated at 400 N•m (303 ft•lbs) @ 1800 rpm, which agrees with what I saw today.

-dave
 

taylorm

Member
Following up on this request, I was watching my dash box today (first prototype so no data logged…) and I could get 300 foot pounds indicated during full-on pedal-to-the-floor launches, with the MAF reading up around 160 g/sec.

The charts vary, but I found web pages claiming that the om647 is rated at 400 N•m (303 ft•lbs) @ 1800 rpm, which agrees with what I saw today.

-dave
I cannot get my Autel AP200 to communicate with the TCM, so unable to check that torque spec. Do you know if that value is calculated or actually measured?

I also can't read MAF in g/sec. Mine is showing as mg/hub and at full throttle it reads 1150 mg/Hub. Is there a way to convert that to g/sec or vice versa?

Really appreciate all the help here...
 

taylorm

Member
Injected fuel quantity isn't viewable on the AP200, Only advanced scan tools can access that, as its behind a second level of security/diagnostics on the ECM.

You may be able to connect to the TCM and view the output torque value. Not sure if that will be helpful though.

The MAF reading is mg per revolution (hub). Which is a valid measurement. I don't recall the normal values off hand. The mg/hub value should increase with engine load, but not necessarily with RPM (mg/second would increase with RPM).
Have you been able to read the output torque value from the TCM successfully on the T1N's? If so, what scanner were you using, and do you know if it is a measured or a calculated value?
 

Midwestdrifter

Engineer In Residence
Have you been able to read the output torque value from the TCM successfully on the T1N's? If so, what scanner were you using, and do you know if it is a measured or a calculated value?
My Autel Md802 reads it just fine. Its a calculated value supplied by the ECM and is based on fuel injected.
 

Midwestdrifter

Engineer In Residence
I also can't read MAF in g/sec. Mine is showing as mg/hub and at full throttle it reads 1150 mg/Hub. Is there a way to convert that to g/sec or vice versa?

Hub is RPM/2 So take your current RPM (lets say 3000). If you have 10mg/hub then you have 10*1500=15,000mg/minute, or 250mg/second
 

Nautamaran

2004 140” HRC 2500 (Crewed)
I cannot get my Autel AP200 to communicate with the TCM, so unable to check that torque spec. Do you know if that value is calculated or actually measured?

I also can't read MAF in g/sec. Mine is showing as mg/hub and at full throttle it reads 1150 mg/Hub. Is there a way to convert that to g/sec or vice versa?

Really appreciate all the help here...
There are no strain gauges in the system so I expect it’s a calculated value based on engine fueling and torque converter slip (for TC output torque, which is what the TCM needs to manage/predict shift pressures). I don’t know this for certain, but the Xentry tools certainly display a TC input & output torque value. I thought my AP200 does too? You’d have to go down through the “Scan” menu and select the correct Sprinter model (901 or WD…) then select the correct transmission module (I think it’s labeled “EGS” but it’s been quite a while…)

Converting mg/Hub to g/sec requires the engine rpm:

Given:
X mg/Hub = X mg / 2 rotations
Y rpm = Y rotations / minute

XY = (mg / 2 rotation) x (rotation / minute)
which rearranges into
XY = (mg x rotation) / (2 minute x rotation)
XY = mg / 2 minute

Z gram / second = XY (mg / 2 minute) x (2 min / 120 seconds) x (1 gram / 1000 mg)

So to convert MAF from mg/Hub into grams/second you multiply mg/Hub times RPM, then divide by 120,000

-dave

(with thanks to my high school math teacher Mr. MacDonald for drilling into us that you can always multiply by your choice of “one” - which is terrific for working out this sort of unit conversion on the fly!)
 

taylorm

Member
Ok, so at full throttle and engine RPM of 2824 I was achieving air mass of 1150 mg/Hub. Converting this to g/sec per your methodology would yield 54 g/sec.

This would be pretty dismal compared to the 160 g/sec you quoted above.

However, I also can see where you are making pretty good engine torque on relatively low air flow on your data table above:

TIMESpeed
(mph)
LOD
%
Coolant
Temp
(F)
Intake Air
Pressure
(psi)
MAP
(psi)
Turbo
%pwm
(0=full)
MAF
(g/sec)
Fuel RP
(psi)
EGR
(%pwm)
Engine
Torque
(ft-lbs)
Converted
Torq output
(ft-lbs)
Engine
RPM
Actual
Gear
13:32:582599177.3512.87632.85765125.032224329.82229.39229.3925892nd
13:04:486199161.1512.89129.4787496.022020336.5222.02222.0223255th
13:08:037399185.4512.78932.27761129.972265829.89221.28221.2827935th
13:04:233699152.5112.90531.27665118.052077728.69217.59217.5924323rd
13:06:186199181.3112.83232.16162139.44227225.29215.38215.3828284th
13:06:135099180.4112.81833.82859158.412300929.47209.48209.4832533rd
13:04:295399153.0512.80331.92954150.752310434.73205.05205.0534103rd
13:42:283399181.8512.97721.7799546.381465822.98170.39170.3915674th
13:39:232897182.7512.93429.9867487.141829220.86234.56234.5619063rd
13:42:343494182.7512.93427.1297762.191685814.38222.76222.7616104th
13:42:383494183.6512.93426.9847761.521714515.55220.54220.5416214th
13:07:596892185.0912.81831.68269115.03212565.29204.32204.3225945th
13:02:474792134.8712.93428.5367472.641768623.24202.84202.8418235th
13:03:49192146.5712.99217.1398654.83127469.98127.6183.6616531st
12:56:5349159.8112.93418.1989354.331335210122.44154.916001st
13:38:394890183.1112.93426.9127675.64178455.29216.85216.8518575th
13:34:275190185.9912.91929.4496580.361577323.53200.63200.6319955th
13:34:084090182.2112.84731.04468115.552138332.96199.89199.8926183rd
13:02:444490133.7912.94828.1598269.971698519.64196.2196.217405th
For example 234.56 ft-lbs at 87 g/sec or 223 ft-lbs at 62 g/sec.

You would think the engine would throw a code if it was getting very low MAF readings relative to expected at throttle/load levels...

I'll see if I can connect to the TCM again via AP200. I tried both Android and Apple and just kept getting the UNKNOWN VARIANT '' error message.
 

taylorm

Member
Ok finally got connected to the TCM and was able to observe calculated torque values.

Unfortunately, AP200 doesn't allow me to log data, so I am just relying on some screenshots from a 2nd gear pull:

Max Torque: 250 ft-lbs
Torque at 1200 RPM: 83 ft-lbs
Torque at 1800 RPM: 178 ft-lbs
Torque at 2350 RPM: 242 ft-lbs
Max Torque achieved ~2,500 RPM

Attached is a screenshot of the torque pulling from a standstill through 3rd gear (look at the line graph):
IMG_6734.PNG

Strange that it stays flatlined on 250 during the third gear (through 2500-3500 RPM likely) instead of falling off like it showed on the two other gears.

Thoughts? Is this enough to show a shop to determine there is a problem with the van? Any way to determine if cause of the low power is on the engine side or the torque converter side? Do the low MAF readings (1150 mg/hub noted above) show enough support for having this be an engine problem?

I will also say the van feels especially sluggish right off the line under no boost...
 

taylorm

Member
Following up on this request, I was watching my dash box today (first prototype so no data logged…) and I could get 300 foot pounds indicated during full-on pedal-to-the-floor launches, with the MAF reading up around 160 g/sec.

The charts vary, but I found web pages claiming that the om647 is rated at 400 N•m (303 ft•lbs) @ 1800 rpm, which agrees with what I saw today.
Do you recall what around what RPM you were hitting max torque at? Was it closer to the 1800 rpm rating or 2500-2700 RPM like I've been measuring?
 

Nautamaran

2004 140” HRC 2500 (Crewed)
Do you recall what around what RPM you were hitting max torque at? Was it closer to the 1800 rpm rating or 2500-2700 RPM like I've been measuring?
Right after launching, as I (quickly) pass 2000 rpm. I’ll see if I can pull similar graphs for you from my AP200.

-dave
 

fixspr

Active member
Same data file from Sept 22, 2020, pared down and sorted by LOD and Engine Torque

TIMESpeed
(mph)
LOD
%
Coolant
Temp
(F)
Intake Air
Pressure
(psi)
MAP
(psi)
Turbo
%pwm
(0=full)
MAF
(g/sec)
Fuel RP
(psi)
EGR
(%pwm)
Engine
Torque
(ft-lbs)
Converted
Torq output
(ft-lbs)
Engine
RPM
Actual
Gear
13:32:582599177.3512.87632.85765125.032224329.82229.39229.3925892nd
13:04:486199161.1512.89129.4787496.022020336.5222.02222.0223255th
13:08:037399185.4512.78932.27761129.972265829.89221.28221.2827935th
13:04:233699152.5112.90531.27665118.052077728.69217.59217.5924323rd
13:06:186199181.3112.83232.16162139.44227225.29215.38215.3828284th
13:06:135099180.4112.81833.82859158.412300929.47209.48209.4832533rd
13:04:295399153.0512.80331.92954150.752310434.73205.05205.0534103rd
13:42:283399181.8512.97721.7799546.381465822.98170.39170.3915674th
13:39:232897182.7512.93429.9867487.141829220.86234.56234.5619063rd
13:42:343494182.7512.93427.1297762.191685814.38222.76222.7616104th
13:42:383494183.6512.93426.9847761.521714515.55220.54220.5416214th
13:07:596892185.0912.81831.68269115.03212565.29204.32204.3225945th
13:02:474792134.8712.93428.5367472.641768623.24202.84202.8418235th
13:03:49192146.5712.99217.1398654.83127469.98127.6183.6616531st
12:56:5349159.8112.93418.1989354.331335210122.44154.916001st
13:38:394890183.1112.93426.9127675.64178455.29216.85216.8518575th
13:34:275190185.9912.91929.4496580.361577323.53200.63200.6319955th
13:34:084090182.2112.84731.04468115.552138332.96199.89199.8926183rd
13:02:444490133.7912.94828.1598269.971698519.64196.2196.217405th
What are you using to get all this data a DAD?
 

Nautamaran

2004 140” HRC 2500 (Crewed)
What are you using to get all this data a DAD?
I used a homemade arduino-based gadget dubbed the Nautabox, which polls the diagnostic lines of the engine and transmission and writes continually to an SD card. Parts got scarce during Covid and I got out of the habit of building them, but there are about 100 units out in the wild (owned by forum members).

Read threads “cracking the k-line” or “who wants an arduino based aux display” for the sordid details.

-dave
 

BubzI

Member
Ok finally got connected to the TCM and was able to observe calculated torque values.

Unfortunately, AP200 doesn't allow me to log data, so I am just relying on some screenshots from a 2nd gear pull:

Max Torque: 250 ft-lbs
Torque at 1200 RPM: 83 ft-lbs
Torque at 1800 RPM: 178 ft-lbs
Torque at 2350 RPM: 242 ft-lbs
Max Torque achieved ~2,500 RPM

Attached is a screenshot of the torque pulling from a standstill through 3rd gear (look at the line graph):
View attachment 244333

Strange that it stays flatlined on 250 during the third gear (through 2500-3500 RPM likely) instead of falling off like it showed on the two other gears.

Thoughts? Is this enough to show a shop to determine there is a problem with the van? Any way to determine if cause of the low power is on the engine side or the torque converter side? Do the low MAF readings (1150 mg/hub noted above) show enough support for having this be an engine problem?

I will also say the van feels especially sluggish right off the line under no boost...
Any special tricks to get the AP200 communicating with the TCM? My AP200 doesn't want to talk TCU with my 2006. Thanks
 

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