Need help with a LB7 / LBZ conversion truck in SW NY state.

[036.6turbo]

Agreed, certainly could be.



This is important on LBZ+ platform.


Not all, at most I've seen them pull down a set of 4.

When you say LBZ+, you’re referring to inputting the injector flow rates in the ECM like the LML platform.

LML was the first I had heard of, I didn’t think the LBZ or LMM required that?

Anyhow nothing he did helped either.


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[Cougar281]

Flow rate programming started with the LBZ.

I should also add that if the flow rates don't match in the ECM and GPCM (such as due to an ECM swap), you'll get a DTC about it, and even if the flow rates aren't programmed right at all or just don't match, I don't THINK that'll prevent the truck from starting... it just may be 'sub-optimal' with balance rates not being accurate and maybe a rougher idle, depending on how far out the actual injectors are from what's been programmed.

An interesting aside, how do you handle flow rates with oversized injectors? For LBZ and newer, does the company providing oversized injectors provide flow rate codes to program in?

 

[036.6turbo]

Flow rate programming started with the LBZ.

I should also add that if the flow rates don't match in the ECM and GPCM (such as due to an ECM swap), you'll get a DTC about it, and even if the flow rates aren't programmed right at all or just don't match, I don't THINK that'll prevent the truck from starting... it just may be 'sub-optimal' with balance rates not being accurate and maybe a rougher idle, depending on how far out the actual injectors are from what's been programmed.

I did the swap in 2016, truck ran very well.

Did not program any injector flow rates at that time.

But, the glow plug control module and the ECM con from the same donor truck.

Must be with the ECM replacement it needed to be done.

Odd thing is I never saw anything about that in service information related the programming a new ECM.

I must have overlooked it.

So this visiting tech was NOT drunk and disorderly, actually did bring something of value to the situation.

Obviously was somewhat knowledgeable.

And he couldn’t figure it out either.

Hmmm


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[Cougar281]

The thing with timing and diesels, is if the valve/piston timing is correct (or close enough), but for some reason, the ECM is out of time, like maybe a sheared pin, it would still make sense for it to run off external fuel - if the injectors aren't injecting at the right time, or not at all due to seeing things being off', it won't fire, or might cough, but with external fuel, it could run...

I don't know what the tolerances are with regards to cam/crank correlation and firing the injectors, but say there's a sheared pin, and the tolerances are off 'just enough' for the ECM to not supply fuel, but no PTV or other damage, and adding ether or another fuel, it'll run... Diesels are real simple with compression and fuel, they'll fire. But if timing is off, and fuel isn't being injected at the right point, it won't ignite, but external fuel will still ignite. With gassers, they just won't light if timing is out because of the spark requirement. If spark fires out of time...

To give a gasser example, I had a friends 4 cyl Jeep that kicked my butt... it would sputter once and just crank, and when I probed the coil, I found that after some cranking, it would stop firing the coils. Turned out the timing belt jumped a tooth or two. But while it apparently detected a cam/crank correlation error, shutting down spark, I never got a P0018 (or any other DTC). Had I gotten a P0018, I would have gotten it running much faster.

So in this case, if a pin is sheared and the cam/crank are out of sync 'just enough', it might still run on external fuel...

 

[DAVe3283]

Didn't James or someone just report a similar issue where a truck wouldn't run despite all signs pointing to it working and it turned out the diesel was mostly water and wouldn't burn?

I wonder if something similar is happening here?

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[Chevy1925]

Didn't James or someone just report a similar issue where a truck wouldn't run despite all signs pointing to it working and it turned out the diesel was mostly water and wouldn't burn?

I wonder if something similar is happening here?

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We had a ford 6.7 comin a month or two ago that the fuel tank was filled with def and the driver never told us. Dont think he wanted the company he drove for to know. He made it 100 miles after we did a drain, flush and fill before the cp4 died

Anyhow, quick sample of fuel in a clear bottle will tell ya real quick.

 

[Cougar281]

Didn't James or someone just report a similar issue where a truck wouldn't run despite all signs pointing to it working and it turned out the diesel was mostly water and wouldn't burn?

I wonder if something similar is happening here?

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Well, in this case, it 'seems' that the ECM isn't commanding fuel for some reason based on what's been posted. I'm not there, so...

 

[036.6turbo]

The thing with timing and diesels, is if the valve/piston timing is correct (or close enough), but for some reason, the ECM is out of time, like maybe a sheared pin, it would still make sense for it to run off external fuel - if the injectors aren't injecting at the right time, or not at all due to seeing things being off', it won't fire, or might cough, but with external fuel, it could run...

I don't know what the tolerances are with regards to cam/crank correlation and firing the injectors, but say there's a sheared pin, and the tolerances are off 'just enough' for the ECM to not supply fuel, but no PTV or other damage, and adding ether or another fuel, it'll run... Diesels are real simple with compression and fuel, they'll fire. But if timing is off, and fuel isn't being injected at the right point, it won't ignite, but external fuel will still ignite. With gassers, they just won't light if timing is out because of the spark requirement. If spark fires out of time...

To give a gasser example, I had a friends 4 cyl Jeep that kicked my butt... it would sputter once and just crank, and when I probed the coil, I found that after some cranking, it would stop firing the coils. Turned out the timing belt jumped a tooth or two. But while it apparently detected a cam/crank correlation error, shutting down spark, I never got a P0018 (or any other DTC). Had I gotten a P0018, I would have gotten it running much faster.

So in this case, if a pin is sheared and the cam/crank are out of sync 'just enough', it might still run on external fuel...

I understand what you are saying I just cannot reconcile in my mind that if the ECM is looking for a correlation between the cam sensor and crank sensor (which I'm sure it is), that it wouldn't set a code when it didn't see it. Again, no codes in the ECM.

We had a ford 6.7 comin a month or two ago that the fuel tank was filled with def and the driver never told us. Dont think he wanted the company he drove for to know. He made it 100 miles after we did a drain, flush and fill before the cp4 died

Anyhow, quick sample of fuel in a clear bottle will tell ya real quick.

I not there, but early on in this diagnosis, he bypassed the fuel tank / system with a small 9psi external pump feeding from a jug of fresh diesel, directly to the CP3.

Years ago, they had an incident where the incorrect pump was chosen at a fuel stop. The tank was dropped then and gasoline cleaned out. After that he's pretty keen on what goes in the tank.

 

[036.6turbo]

Probably not seeing the 60RPMs while just cranking, so no code set.

DTC P0340-P0342
DTC DescriptorsDTC P0340
Camshaft Position (CMP) Sensor Circuit
DTC P0341
Camshaft Position (CMP) Sensor Performance
Diagnostic Fault Information
Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Circuit​	Short to Ground​	High Resistance​	Open​	Short to Voltage​	Signal Performance​
CMP 5-Volt Reference​	P0097, P0652, P0642, P0340​	P0340​	P0340​	P0098, P0336, P0341, P0653, P0643​	—​
CMP Sensor Signal​	P0340​	P0340​	P0340​	P0340​	—​
CMP Low Reference​	—​	P0340, P0237​	P0340​	—​	—​

Typical Scan Tool DataCam Signal Present

Circuit​	Normal Range​	Short to Ground​	Open​	Short to Voltage​
Operating Conditions: Engine running​
CMP 5-Volt Reference Voltage​	Yes​	No​	No​	Yes​
CMP Sensor Signal​	Yes​	No​	No​	No​
CMP Low Reference​	Yes​	—​	No​	—​

Circuit/System Description
The hall effect camshaft position (CMP) sensor produces 3 ON/OFF pulses for each revolution of the camshaft. The CMP output is pulse width encoded. The engine control module (ECM) uses the CMP and crankshaft position (CKP) output pulses to determine the engine speed and position. The CMP is connected directly to the ECM by the following circuits:

• The 5-volt reference circuit
• The low reference circuit
• The CMP sensor signal circuit

Conditions for Running the DTC

• The ignition is ON.
• The engine is turning faster than 60 RPM.
• DTC P0340 and P0341 run continuously when the above conditions are met.

Conditions for Setting the DTC
P0340
The ECM does not see a CMP sensor signal for more than 2 seconds.

P0341
The ECM determines that the CMP sensor signal is out of range for less than 2 seconds.

Action Taken When the DTC Sets

 

[036.6turbo]

Crankshaft codes

DTC P0335 or P0336
Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC DescriptorsDTC P0335
Crankshaft Position (CKP) Sensor Circuit
DTC P0336
Crankshaft Position (CKP) Sensor Performance
Diagnostic Fault Information

Circuit​	Short to Ground​	Open/High Resistance​	Short to Voltage​	Signal Performance​
CKP 5-Volt Reference Voltage​	P0642, P0643​	P0335, P0336​	P0335, P0336, P0341, P0642, P0643​	P0336​
CKP Sensor Signal​	P0335, P0336​	P0335, P0336​	P0335, P0336​	P0336​
CKP Low Reference​	—​	P0335, P0336​	—​	P0336​

Typical Scan Tool DataCKP Sensor Signal Present

Circuit​	Normal Range​	Short to Ground​	Open​	Short to Voltage​
Operating Conditions: Engine Running​
CKP 5-Volt Reference Voltage​	Present​	No​	No​	No​
CKP Sensor Signal​	Present​	No​	No​	No​
CKP Low Reference​	Present​	—​	No​	No​

Circuit/System Description
The hall effect crankshaft position (CKP) sensor signal indicates the crankshaft speed and position. There are 57 teeth on the front of the crankshaft sprocket, plus a sync gap. The CKP sensor will output an ON/OFF pulse as each window passes the sensing element. The CKP sensor is connected directly to the engine control module (ECM) by the following circuits:

• The 5-volt reference circuit
• The low reference circuit
• The signal circuit

Conditions for Running the DTCP0335

• The engine is cranking or running.
• The camshaft position (CMP) sensor signal is present.
• DTC P0335 runs continuously when the above conditions are met.

P0336

• The engine is cranking or running.
• DTC P0336 runs continuously when the above condition is met.

Conditions for Setting the DTC
P0335
The ECM determines no signal from the CKP sensor for less than 8 seconds.

P0336
The ECM determines that the CKP sensor signal is out of range for less than 2 seconds.

Action Taken When the DTC Sets

• The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
• The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

Conditions for Clearing the MIL/DTC

• The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
• Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

• An intermittent CKP sensor signal may cause DTC P0336 to set. Wiggle the wiring harness with the engine running and observe the CKP Sensor Pulses Missed parameter on the scan tool. If the parameter indicates anything other than 0, there is an intermittent condition.
• Abnormal drivetrain noise or vibration may cause DTC P0336 to set.
• Inspect for insufficient fuel.

 

[Cougar281]

I understand what you are saying I just cannot reconcile in my mind that if the ECM is looking for a correlation between the cam sensor and crank sensor (which I'm sure it is), that it wouldn't set a code when it didn't see it. Again, no codes in the ECM.

Agreed - that's what had me pulling my hair out with that Jeep and then massive facepalm when I found it was out of time.

 

[2004LB7]

if it doesn't run on ether or gasoline then you need to check compression

 

[036.6turbo]

if it doesn't run on ether or gasoline then you need to check compression

It will run on ether.

 

[036.6turbo]

Agreed - that's what had me pulling my hair out with that Jeep and then massive facepalm when I found it was out of time.

Last time we spoke he was going to see if the pin had sheared.