2015 GM 3500 6.0L - Need help with engine stumble

[burbguy82]

Scan tools have latency issues, This is where data loggers & scopes come in. A couple here has HpTuners but I always forget who?? Their scanner is more of a Data Logger than it is a Scan Tool.

I have HPT, and the data between the two (Topdon and HPT) are very close if not exactly the same as far as fuel trims and the like. I have though about a scope. Seems like it is a nessessity for problems like this, and a big time saver, if you know how to use it.

Is there anything specific I should be looking at datalogging?

 

[clinebarger]

Graph the throttle %, One of the TPS sensors (I prefer the rising one), And the APPS.

Electronic throttle systems are usually quick to set DTC's & limp if anomalies are present.

 

[burbguy82]

Graph the throttle %, One of the TPS sensors (I prefer the rising one), And the APPS.

Electronic throttle systems are usually quick to set DTC's & limp if anomalies are present.

So it will not allow me to record on HPT. Might be because the tune is locked, long story.

Problem is not due to tune as it has been fine for 6 years. Anyway......Ill do my best to describe:

-TPS is very jumpy on graph, with no input at pedal, fluctuates from 0-30 percent, no pedal input. on pedal input from 0% TPS with goe from 25% or so to 5% then up to 42% max engine off.
-pedal input and sensor signal, all the way 100%, engine off, is smooth and linear
-engine off, pedal 100%, TPS only goes to 42%
-TPS can be commanded to 100%

I did get a DTC for loss comms to computer, no CEL. U0100

TCM and ECM results are the same, as far as APPS and TPS, which lead me to think that computers are not at fault?
APPS and tps should match correct?

 

[burbguy82]

Graph the throttle %, One of the TPS sensors (I prefer the rising one), And the APPS.

Electronic throttle systems are usually quick to set DTC's & limp if anomalies are present.

Also, show not going into WOT.

The 2 TPS sensor do not agree, one will peg at 76% and the other at 42 % engine off pedal at 100%

Do you think it will need a TPS /full unit?

NAPA or GM Genuine from online vendor?

Thanks

 

[clinebarger]

You have to data log while the engine is running.

0-20% is considered the "Idle" range & will move around a lot.

E78 & E92 ECM's are "torque model based" without getting to far into the weeds....This is the best explanation I can come up with....

Once the MAP reaches 100kpa/14.5psi, The throttle blade will not open any further....The engine is ingesting all the air it possibly can, This typically happens at 80-90% on a L96. This allows GM to use the same size throttle body (87mm) on several different engines from a 5.3L to a 6.6L.

 

[burbguy82]

You have to data log while the engine is running.

0-20% is considered the "Idle" range & will move around a lot.

E78 & E92 ECM's are "torque model based" without getting to far into the weeds....This is the best explanation I can come up with....

Once the MAP reaches 100kpa/14.5psi, The throttle blade will not open any further....The engine is ingesting all the air it possibly can, This typically happens at 80-90% on a L96. This allows GM to use the same size throttle body (87mm) on several different engines from a 5.3L to a 6.6L.

having a closer look at the HPT scanner....that thing is pretty good. Very quick reacting.

I am going to try another route for recording the datalog on hpt.

I learned that the throttle, and idle control are done at the throotle body, using the butterfly as the idle control.

Idle has been off also, lower than what it should be.

funny thing, trying ro diagnose all these thing from afar...and listening to the customers.....is that they alway leave out that one little thing. vhappems in the plumbing field also....

Ill get back when i have more data, thanks for the help

 

[burbguy82]

So update.

Drove yesterday, and on my scanner #4 5 6 7 injectors were showing to be "unrecognizable" or out of range.

Later while still having the scanner hooked up, the issue went away.

 

[D60]

So update.

Drove yesterday, and on my scanner #4 5 6 7 injectors were showing to be "unrecognizable" or out of range.

Later while still having the scanner hooked up, the issue went away.

How does it drive when they show MIA?

 

[burbguy82]

How does it drive when they show MIA?

loss of power, but I am not sure if it is a wiring thing or an actual mechanical issue with the injectors. I can command them off at will. I wounder if the reading of "unrecognized state" means that they are open of with enough resistance for the computer to not be able to register? Never seen such a thing in my limited experience.

Fuel trims were way in the negatives.

 

[snarl]

@burbguy82 Is 4 5 6 7 one bank of the engine? Maybe a lose connection in the harness.

 

[burbguy82]

@burbguy82 Is 4 5 6 7 one bank of the engine? Maybe a lose connection in the harness.

No, they are actually on both sides

Really, I wish it was all on one side, as it would be easier to diagnose.

Good thought though, thanks for sharing

 

[clinebarger]

loss of power, but I am not sure if it is a wiring thing or an actual mechanical issue with the injectors. I can command them off at will. I wounder if the reading of "unrecognized state" means that they are open of with enough resistance for the computer to not be able to register? Never seen such a thing in my limited experience.

Fuel trims were way in the negatives.

These are all the Injector circuit DTC's, I'm almost positive they're set to "MIL on second error" in the calibration.


DTC P0201
Cylinder 1 Injector Control Circuit

DTC P0202
Cylinder 2 Injector Control Circuit

DTC P0203
Cylinder 3 Injector Control Circuit

DTC P0204
Cylinder 4 Injector Control Circuit

DTC P0205
Cylinder 5 Injector Control Circuit

DTC P0206
Cylinder 6 Injector Control Circuit

DTC P0207
Cylinder 7 Injector Control Circuit

DTC P0208
Cylinder 8 Injector Control Circuit

DTC P0261
Cylinder 1 Injector Control Circuit Low Voltage

DTC P0262
Cylinder 1 Injector Control Circuit High Voltage

DTC P0264
Cylinder 2 Injector Control Circuit Low Voltage

DTC P0265
Cylinder 2 Injector Control Circuit High Voltage

DTC P0267
Cylinder 3 Injector Control Circuit Low Voltage

DTC P0268
Cylinder 3 Injector Control Circuit High Voltage

DTC P0270
Cylinder 4 Injector Control Circuit Low Voltage

DTC P0271
Cylinder 4 Injector Control Circuit High Voltage

DTC P0273
Cylinder 5 Injector Control Circuit Low Voltage

DTC P0274
Cylinder 5 Injector Control Circuit High Voltage

DTC P0276
Cylinder 6 Injector Control Circuit Low Voltage

DTC P0277
Cylinder 6 Injector Control Circuit High Voltage

DTC P0279
Cylinder 7 Injector Control Circuit Low Voltage

DTC P0280
Cylinder 7 Injector Control Circuit High Voltage

DTC P0282
Cylinder 8 Injector Control Circuit Low Voltage

DTC P0283
Cylinder 8 Injector Control Circuit High Voltage

 

[burbguy82]

These are all the Injector circuit DTC's, I'm almost positive they're set to "MIL on second error" in the calibration.


DTC P0201
Cylinder 1 Injector Control Circuit

DTC P0202
Cylinder 2 Injector Control Circuit

DTC P0203
Cylinder 3 Injector Control Circuit

DTC P0204
Cylinder 4 Injector Control Circuit

DTC P0205
Cylinder 5 Injector Control Circuit

DTC P0206
Cylinder 6 Injector Control Circuit

DTC P0207
Cylinder 7 Injector Control Circuit

DTC P0208
Cylinder 8 Injector Control Circuit

DTC P0261
Cylinder 1 Injector Control Circuit Low Voltage

DTC P0262
Cylinder 1 Injector Control Circuit High Voltage

DTC P0264
Cylinder 2 Injector Control Circuit Low Voltage

DTC P0265
Cylinder 2 Injector Control Circuit High Voltage

DTC P0267
Cylinder 3 Injector Control Circuit Low Voltage

DTC P0268
Cylinder 3 Injector Control Circuit High Voltage

DTC P0270
Cylinder 4 Injector Control Circuit Low Voltage

DTC P0271
Cylinder 4 Injector Control Circuit High Voltage

DTC P0273
Cylinder 5 Injector Control Circuit Low Voltage

DTC P0274
Cylinder 5 Injector Control Circuit High Voltage

DTC P0276
Cylinder 6 Injector Control Circuit Low Voltage

DTC P0277
Cylinder 6 Injector Control Circuit High Voltage

DTC P0279
Cylinder 7 Injector Control Circuit Low Voltage

DTC P0280
Cylinder 7 Injector Control Circuit High Voltage

DTC P0282
Cylinder 8 Injector Control Circuit Low Voltage

DTC P0283
Cylinder 8 Injector Control Circuit High Voltage

Not a one DTC. Read by my Topdon Phoenix Elite and HPT scanner. But the scanner was showing malfunction on those.....#4567 It did show a U0100.

What would be considered "2nd error"?

I watched this happen for at least 5 mins......I would thin kthat would register.........

All in all I am still leaning towards yalls first idea of injectors sticking.....but not I am thinking of ECM issue............dynamite would fix this right up.

If they were in fact sticking, you reckon the would cause a "malfunction" but no DTC, or would you move toward bad ECM and dynamite?

 

[clinebarger]

Not familiar with those PID's being used by GM. Ford is known to use component/circuit fault PID's.

What module is setting U0100?

Engine control module detects the fuel injector control circuit fault for greater than 2 s.....This would need to happen twice to set a service engine soon lamp.

 

[burbguy82]

Not familiar with those PID's being used by GM. Ford is known to use component/circuit fault PID's.

What module is setting U0100?

Engine control module detects the fuel injector control circuit fault for greater than 2 s.....This would need to happen twice to set a service engine soon lamp.

The scanner is telling me that the ECBM and ECM are losing comms. This happens every so often. There has been some issue with this since it was new, not connected to the current abnormal running issue, or so I would correlate. I do not think they are connected.

I wonder if there is a "limp mode" that it is going into, when it senses this issue (the weird backfire previously mentioned as the issue on this thread). Still no CEL, just a "safe mode"

I drove it this morning, no problem, no stumble, good power, etc. IU'll bet if I go start it and drive it within the next hour or two, it will malfunction.

One thing I noticed is that when running like crap, the ignition timing retards to -40, but when good, seems to be advanced at 16 or so. THis would lead me to think that the ECM is doing its job. Would you agree?

I think the DTC for ECBM (no CEL) has to do with the monkeys who installed the flatbed at CM truck beds.

I have had issue with the Trailer Brake control module from time to time, especially when wet. Issue is, I think in order to gain visual in the harness and connections, one would have to drop either tank, or remove the bed. It is roughly a 1500lbs bed.

It is a chassis cab.

 

[burbguy82]

Any additional thoughts?

 

[burbguy82]

so update:

Cleaned injectors twice

Got new vin matched injectors and installed them yesterday. There is a noticeable different if response power, sound and smoothness. But the fuel trims are still way in the negative.

I reset the fuel trims and changed the engine oil.

Fuel pressure is at 65, which i am in the understanding is high. It does not fluctuate on throttle snap.

 

[mattd]

Is the engine oil diluted with fuel?

 

[burbguy82]

Is the engine oil diluted with fuel?

does not smell of it. nor dones it ignite.

forgot to get sample when i changed the oil, like an idiot.

oil change was just a protective measure.

 

[burbguy82]

So recently I have still been messing with this issue. Got the AllData DIY thing online to get some more specific specs on the fuel system. In a flow chart, I found that anything above 60psi = no good. I have 65psi running, constant.

Call up the dealer for some parts availability, and got a price for a factory fuel pump for it, and they said they would not give me the part number. .........Figures.

ordered new pump from dealer