'01 3500 LB7 P0202 P0203 P0205 P0208 P1262 LB7 Issue after head gasket replacement

[Samisunjp]

Hey,

Having an issue I've been trying to figure out of two weeks,

Replaced head gaskets, put back together got truck running but it cranks a lot before starting. Getting codes P0202 P0203 P0205 P0208 P1262. Sent FICM off to get worked on and put it back in, no change. Replaced engine wiring harness, no change. Checked resistance of injectors harnesses and all are in spec. Checked bail connectors and wires and none seem to be damaged. Cleaned all contacts with CRC and dielectric grease.

Really not sure where to go from here, any help at all would be appreciated.

 

[2004LB7]

Two thoughts, one or more connections on the injector terminals are loose or you have swapped one or more with the wrong injectors.

What did you use to check the resistance and what reading did you get? A better measurement is an inductive tester

 

[TheBac]

DTC P1262 Circuit DescriptionThe fuel injection control module (FICM) supplies high voltage to each fuel injector on the ignition voltage circuits. The FICM energizes each fuel injector by grounding the command circuit between the FICM and the fuel injector. The FICM monitors the status of the ignition voltage circuits and the fuel injector command circuits. When a fuel injector circuit condition is detected by the FICM, all of the fuel injectors on the affected ignition voltage circuit will be disabled. If a circuit condition is detected on a fuel injector circuit for cylinders 1, 4, 6, or 7, DTCs P0201, P0204, P0206, P0207 will set, along with DTC P1261. If a circuit condition is detected on a fuel injector circuit for cylinders 2, 3, 5, or 8, DTCs  P0202, P0203, P0205, P0208 will set, along with DTC P1262.

Just something I found. I agree with Jason, sounds like you've got an issue with the injector connections.

 

[Ron Nielson]

• Group 1-DTC P2146 with injectors 1 and 4
• Group 2-DTC P2149 with injectors 6 and 7
• Group 3-DTC P2152 with injectors 2 and 5
• Group 4-DTC P2155 with injectors 3 and 8

When a fuel injector circuit condition is detected by the ECM, the affected fuel injectors will be disabled and may disable the affected group of fuel injectors.

Looks like it's group 3 and 4

 

[Samisunjp]

Two thoughts, one or more connections on the injector terminals are loose or you have swapped one or more with the wrong injectors.

What did you use to check the resistance and what reading did you get? A better measurement is an inductive tester

Using ohms on a voltmeter. Getting between .1-.5 at the injector itself between terminals. same reading at the pigtail out of valve cover, and same reading from ficm harness to the injectors

 

[Samisunjp]

Two thoughts, one or more connections on the injector terminals are loose or you have swapped one or more with the wrong injectors.

What did you use to check the resistance and what reading did you get? A better measurement is an inductive tester

Also I thouhght the injector harnesses are interchangeable, right?

 

[Samisunjp]

Checked every connection from the FICM plug down to the injectors, including pigtails.

Injector 2 connection was loose completely at the injector under valve cover. Tightened that down.

Still same condition for codes and 2,3,5,8 and 1262 codes.

Could that injector have been damaged from runnning with the loose connection? Again all injectors are within spec for resistance (no higher than .5). Could something internal to injector 2 or all the ones on this bank be damaged from the loose connection?

Thanks in advance!

At this point I feel like I've changed everything but the injectors.

 

[2004LB7]

Checked every connection from the FICM plug down to the injectors, including pigtails.

Injector 2 connection was loose completely at the injector under valve cover. Tightened that down.

Still same condition for codes and 2,3,5,8 and 1262 codes.

Could that injector have been damaged from runnning with the loose connection? Again all injectors are within spec for resistance (no higher than .5). Could something internal to injector 2 or all the ones on this bank be damaged from the loose connection?

Thanks in advance!

At this point I feel like I've changed everything but the injectors.

Loose connections doesn't normally do any damage to an injector. It's harder on the FICM though.

Reading the injectors with a DOM is like reading like reading your car speed in mach numbers. The resolution of the meter at that low is not accurate enough to know of one or more is shorted. Too low resistance can be an issue too. That's why an inductive test is far better

You should also check the terminals on the injectors to ground to verify there is not short to ground

 

[TheBac]

Id try to find a good working FICM try in place of yours.

 

[2004LB7]

• Group 1-DTC P2146 with injectors 1 and 4
• Group 2-DTC P2149 with injectors 6 and 7
• Group 3-DTC P2152 with injectors 2 and 5
• Group 4-DTC P2155 with injectors 3 and 8

When a fuel injector circuit condition is detected by the ECM, the affected fuel injectors will be disabled and may disable the affected group of fuel injectors.

Looks like it's group 3 and 4

LB7 and LLY only has two banks. 1, 4, 6, 7 & 2, 3, 5, 8 so when the FICM shuts off a bank you loose half the engine.

 

[Samisunjp]

Loose connections doesn't normally do any damage to an injector. It's harder on the FICM though.

Reading the injectors with a DOM is like reading like reading your car speed in mach numbers. The resolution of the meter at that low is not accurate enough to know of one or more is shorted. Too low resistance can be an issue too. That's why an inductive test is far better

You should also check the terminals on the injectors to ground to verify there is not short to ground

Checked for short to ground at the injectors themselves and nothing.

 

[Samisunjp]

Id try to find a good working FICM try in place of yours.

Sent mine in for rebuild and have another I sourced locally. Both show the same codes.

 

[2004LB7]

Sent mine in for rebuild and have another I sourced locally. Both show the same codes.

That's a good indication you're not doing the testing right or testing the wrong injectors. Maybe check all of them. As stated earlier, maybe invest in an LC tester. There Re a number of cheap ones on Amazon that will do the job

 

[Samisunjp]

Picked up a LC tester from amazon that will be here today. What are good values as far as inductance for the injectors?

 

[darkness]

Just to make sure you’re on the right injectors…drivers side is even and passenger side is odd.

 

[Samisunjp]

Tracking this is the cylinder setup and corresponding injectors. Wire colors on harnesses and expected continuity matches as well.

 

[2004LB7]

Picked up a LC tester from amazon that will be here today. What are good values as far as inductance for the injectors?

I don't recall what the LB7 injectors are. LLY are about 120 uH. Just measure all of them and find any that stand out as different. You might find some variation up to 10 uH but if you see something that is 1/2 what the others are showing then you know it's a problem

 

[Samisunjp]

Alright thank you, I will check all injectors for inductance at the injector posts today and reply back here.

 

[Samisunjp]

So I checked all injectors for inducatance and got .245-.247 for all injectors. Seems like no difference between any of them. Rechecked resistances at the injectors as well and got 0.3, seems within spec. Also rechecked the resistance from the ficm plug to the end of each injector wiring harness pigtail, where it actually connects to the injector. All pins had 0.3 for resistance to the plug.

The only thing I notice is that the wiring at the injector harness for #8 is reversed as far as the injector recieving power from the bottom or top wire connected to it. As far as I understand it does not matter if the injector recieves command or voltage at which peg on the injector, only that the wires trace back to the correct pinout on the ficm plug.

Any ideas?

 

[2004LB7]

Lower the setting on the meter for a higher and more accurate reading